[Federal Register Volume 62, Number 35 (Friday, February 21, 1997)]
[Proposed Rules]
[Pages 7950-7964]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-4353]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 23
[Docket No. 135CE, Notice No. 23-ACE-87]
Special Conditions; Sino Swearingen Model SJ30-2 Airplane
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
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SUMMARY: This notice proposes special conditions for the Sino
Swearingen Aircraft Company Model SJ30-2 airplane. This new airplane
will have novel and unusual design features not typically associated
with normal, utility, acrobatic, and commuter category airplanes. These
design features include a high operating altitude (49,000 feet), engine
location, swept wings and stabilizer, performance characteristics,
large fuel capacity, and protection for the electronic engine control
system, flight, and navigation system from high intensity radiated
fields, for which the applicable regulations do not contain adequate or
appropriate airworthiness standards. This notice contains the
additional airworthiness standards which the Administrator considers
necessary to establish a level of safety equivalent to the
airworthiness standards applicable to these airplanes.
DATES: Comments must be received on or before March 24, 1997.
ADDRESSES: Comments on this proposal may be mailed in duplicate to:
Federal Aviation Administration, Office of the Assistant Chief Counsel,
ACE-7, Attention: Rules Docket Clerk, Docket No. 135CE, Room No. 1558,
601 East 12th Street, Kansas City, Missouri 64106. All comments must be
marked: Docket No 135CE. Comments may be inspected in the Rules Docket
weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.
FOR FURTHER INFORMATION CONTACT: Lowell Foster, Aerospace Engineer,
Standards Office (ACE-110), Small Airplane Directorate, Aircraft
Certification Service, Federal Aviation Administration, Room 1544, 601
East 12th Street, Kansas City, Missouri 64106; telephone (816) 426-
5688.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of
these special conditions by submitting such written data, views, or
arguments as they may desire. Communications should identify the
regulatory docket or notice number and be submitted in duplicate to the
address specified above. All communications received on or before the
closing date for comments specified above will be considered by the
Administrator before taking further rulemaking action on this proposal.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must include a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket No. 135CE.'' The postcard will be date stamped and returned
to the commenter. The proposals contained in this notice may be changed
in light of the comments received. All comments received will be
available, both before and after the closing date for comments, in the
rules docket for examination by interested parties. A report
summarizing each substantive public contact with FAA personnel
concerned with this rulemaking will be filed in the docket.
Background
On October 9, 1995, Sino Swearingen Aircraft Company, 1770 Sky
Place Boulevard, San Antonio, Texas 78216, made application for normal
category type certification of its Model SJ30-2 airplane, a six-to-
eight place, all metal, low-wing, T-tail, twin turbofan engine powered
airplane with fully enclosed retractable landing gear. The SJ30-2 will
have a VMO/MMO of 320 kts/M=.83, and has engines mounted aft
on the fuselage.
Type Certification Basis
Type certification basis of the Model SJ30-2 airplane is: 14 CFR
Part 23, effective February 1, 1965, through amendment 23-51, effective
March 11, 1996; 14 CFR Part 36, effective
[[Page 7951]]
December 1, 1969, through the amendment effective on the date of type
certification; 14 CFR Part 34; exemptions, if any; and any special
conditions that may result from this notice.
Discussion
Sino Swearingen plans to incorporate certain novel and unusual
design features into the SJ30-2 airplane for which the airworthiness
regulations do not contain adequate or appropriate safety standards.
These features include engine location, operation up to an altitude of
49,000 feet, and certain performance characteristics necessary for this
type of airplane that were not envisioned by the existing regulations.
Special conditions may be issued and amended, as necessary, as part
of the type certification basis if the Administrator finds that the
airworthiness standards designated in accordance with 14 CFR Part 21,
Sec. 21.17(a)(1), do not contain adequate or appropriate safety
standards because of novel or unusual design features of an airplane.
Special conditions, as appropriate, are issued in accordance with 14
CFR Part 11, Sec. 11.49 after public notice, as required by Secs. 11.28
and 11.29(b), effective October 14, 1980, and become part of the type
certification basis as provided by part 21, Sec. 21.17(a)(2).
Protection of Systems From High Intensity Radiated Fields (HIRF)
The aviation industry uses electrical and electronic systems that
perform functions required for continued safe flight and landing. Due
to the sensitive solid state components in analog and digital
electronics circuits, these systems, if unprotected, are responsive to
the transient effects of induced electrical current and voltage caused
by the HIRF. The HIRF can degrade electronic systems performance by
damaging components or upsetting system functions.
Furthermore, the electromagnetic environment has changed from the
time when the current requirements were developed. Also, the population
of transmitters has increased significantly and they are radiating
higher energy levels. There is, however, uncertainty concerning the
effectiveness of shielding for HIRF. Additionally, coupling to cockpit
installed equipment through the cockpit window apertures is undefined.
The combined effect of the technological advances in aircraft
design and the changing environment has resulted in an increased level
of vulnerability of electrical and electronic systems required for the
continued safe flight and landing of the aircraft. Effective measures
against the effects of exposure to HIRF must be provided by the design
and installation of these systems.
The accepted maximum energy levels in which civilian airplane
system installations must be capable of operating safely are based on
surveys and analysis of existing radio frequency emitters. These
special conditions require that the airplane be evaluated under these
energy levels for the protection of the electronic system and its
associated wiring harness. These external threat levels are believed to
represent the worst case to which an airplane would be exposed in the
operating environment.
These special conditions require qualification of systems that
perform critical functions, as installed in aircraft, to the defined
HIRF environment in paragraph (1) or, as an option to a fixed value
using laboratory tests, in paragraph (2), as follows:
(1) The applicant may demonstrate that the operation and
operational capability of the installed electrical and electronic
systems that perform critical functions are not adversely affected when
the aircraft is exposed to the HIRF environment, defined below:
Field Strength Volts/Meter
------------------------------------------------------------------------
Frequency Peak Average
------------------------------------------------------------------------
10-100 KHz.................................... 50 50
100-500....................................... 60 60
500-2000...................................... 70 70
2-30 MHz...................................... 200 200
30-70......................................... 30 30
70-100........................................ 30 30
100-200....................................... 150 33
200-400....................................... 70 70
400-700....................................... 4020 935
700-1000...................................... 1700 170
1-2 GHz....................................... 5000 990
2-4........................................... 6680 840
4-6........................................... 6850 310
6-8........................................... 3600 670
8-12.......................................... 3500 1270
12-18......................................... 3500 360
18-40......................................... 2100 750
------------------------------------------------------------------------
or:
(2) The applicant may demonstrate by a laboratory test that the
electrical and electronic systems that perform critical functions can
withstand a peak electromagnetic field strength of 100 volts per meter
(v/m) peak electrical field strength, from 10KHz to 18GHz. When using a
laboratory test to show compliance with the HIRF requirements, no
credit is given for signal attenuation due to installation.
A preliminary hazard analysis must be performed by the applicant
for approval by the FAA to identify electrical and/or electronic
systems that perform critical functions. The term ``critical'' means
those functions whose failure would contribute to, or cause, a failure
condition that would prevent the continued safe flight and landing of
the aircraft. The systems identified by the hazard analysis that
perform critical functions are candidates for the application of HIRF
requirements. A system may perform both critical and non-critical
functions. Primary electronic flight display systems, and their the
associated components, perform critical functions such as attitude,
altitude, and airspeed indication. The HIRF requirements apply only to
critical functions.
Compliance with HIRF requirements may be demonstrated by tests,
analysis, models, similarity with existing systems, or a combination of
these. Service experience alone is not acceptable since such experience
in normal flight operations may not include an exposure to the HIRF
environment. Reliance on a system with similar design features for
redundancy as a means of protection against the effects of external
HIRF is generally insufficient since all elements of a redundant system
are likely to be exposed to the fields concurrently.
Performance
The Sino Swearingen Model SJ30-2 has a main wing with 30 degrees of
leading-edge sweepback that employs leading-edge slats and double-
slotted Fowler flaps. The airplane has a T-tail with trimmable
horizontal stabilizer and 30 degrees of leading-edge sweepback. There
are two medium bypass ratio turbofan engines mounted on the aft
fuselage.
Previous certification and operational experience with airplanes of
like design in the transport category reveal certain unique
characteristics compared to conventional aircraft certificated under
part 23. These characteristics have caused significant safety problems
in the past when pilots attempted takeoffs and landings, particularly
with a large variation in temperature and altitude, using procedures
and instincts developed with conventional airplanes.
One of the major distinguishing features of a swept-wing design not
considered in current part 23 is a characteristically flatter lift
curve without a ``stall'' break near the maximum coefficient of lift,
as in a conventional wing. The ``stall'' separation point may occur at
a much higher angle of attack than the point of maximum lift and the
angle of attack for maximum lift can be only recognized by
[[Page 7952]]
precise test measurements or specific detection systems. This phenomena
is not apparent to a pilot accustomed to operating a conventional
airplane where increasing angle of attack produces increased lift to
the point where the wing stalls. In a swept-wing design, if the pilot
does not operate in accordance with established standards developed
through a dedicated test program, increasing angle of attack may
produce very little lift yet increase drag markedly to the point where
flight is impossible. These adverse conditions may be further
compounded by the characteristics of turbofan engines, including
specified N1/N2 rotational speeds, temperature, and pressure
limits that make its variation in thrust output with changes in
temperature and altitude more complex and difficult to predict. In
recognition of these characteristics, Special Civil Air Regulations No.
SR-422, and follow-on regulations, established weight-altitude-
temperature (WAT) limitations and procedures for scheduling takeoff and
landing for turbine powered transport category airplanes, so the pilot
could achieve reliable and repeatable results under all expected
conditions of operation. This entails specific tests such as minimum
unstick speed, VMU, to ensure that rotation and fly-out speeds are
correct and that the airplane speed schedule will not allow the
airplane to lift off in ground effect and then be unable to accelerate
and continue to climb out. In conjunction with the development of
takeoff and landing procedures, it was also necessary to establish
required climb gradients and data for flight path determination under
all approved weights, altitudes, and temperatures. This enables the
pilot to determine, before takeoff, that a safe takeoff, departure, and
landing at destination can be achieved.
Takeoff
Based upon the knowledge and experience gained with similar high
speed, high efficiency, turbojet airplanes with complex high lift
devices for takeoff and landing, special conditions are proposed for
the performance requirements of takeoff, takeoff speeds, accelerate-
stop distance, takeoff path, takeoff distance, takeoff run, and takeoff
flight path.
Additionally, procedures for takeoff, accelerate stop, and landing
are proposed as those established for operation in service and be
executable by pilots of average skill and include reasonably expected
time delays.
Climb
To maintain a level of safety that is consistent with the
requirements of the proposed special conditions for takeoff, takeoff
speeds, takeoff path, takeoff distance, and takeoff run, it is
appropriate to propose associate requirements that specify climb
gradients, airplane configurations, and consideration of atmospheric
conditions that will be encountered. Special conditions are proposed
for climb with one engine inoperative, balked landing climb, and
general climb conditions.
Landing
Landing distance determined for the same parameters, plus the
effects of wind, is consistent with takeoff information for the range
of weights, altitudes, and temperatures approved for operation.
Further, it is necessary to consider time delays to provide for in-
service variation in the activation of deceleration devices, such as
spoilers and brakes. Special conditions are also proposed to cover
these items.
Trim
Special conditions are issued to maintain a level of safety that is
consistent with the use of VMO/MMO and the requirements
established for previous part 23 jet airplanes. Current standards in
part 23 did not envision this type of airplane and the associated trim
considerations.
Demonstration of Static Longitudinal Stability
To maintain a level of safety consistent with the proposed static
longitudinal stability requirements, it is necessary to establish
corresponding requirements for the demonstration of static longitudinal
stability. Current standards in part 23 did not envision this type of
airplane and the associated stability considerations proposed. In
keeping with the concept of VMO/MMO being a maximum
operational speed limit, rather than a limiting speed for the
demonstration of satisfactory flight characteristics, it is appropriate
to extend the speed for demonstration of longitudinal stability
characteristics from the VMO/MMO of 14 CFR part 23 to the
maximum speed for stability characteristics, VFC/MFC, for
this airplane. A special condition to do this is proposed.
Static Directional and Lateral Stability
In keeping with the concept of VMO/MMO being a maximum
operational speed limit, rather than a limiting speed for the
demonstration of satisfactory flight characteristics, it is appropriate
to extend the speed for demonstration of lateral/directional stability
characteristics from the VMO/MMO of part 23 to the maximum
speed for stability characteristics, VFC/MFC, for this
airplane. A special condition to do this is proposed.
Current transport category regulations have eliminated the
independent lateral stability demonstration requirement (picking up the
low wing with rudder application). This requirement was originally
intended to provide adequate controllability in the event of lateral
control system failure. Because the SJ30 flight control system
reliability requirement are not to current transport category levels,
it is appropriate to retain the prior transport category requirements
to retain the independent dihedral effect and skid recovery
demonstration requirement.
Stall Characteristics
In order to maintain consistency with the level of safety
previously applied to other jet powered small airplanes, it is
appropriate to specify the conditions under which level flight, turning
flight, and accelerated entry stall characteristics should be
demonstrated. Current rules contained in part 23 did not envision this
high performance airplane with the associated high thrust-to-weight
ratio. Special conditions are required to define stall characteristics
demonstrations.
Vibration and Buffeting
The Sino Swearingen Model SJ30-2 will be operated at high altitudes
where stall-Mach buffet encounters (small speed margin between stall
and transonic flow buffet) are likely to occur, which is not presently
addressed in part 23. A special condition is proposed that will require
buffet onset tests and the inclusion of information in the Airplane
Flight Manual (AFM) to provide guidance to the flightcrew. This
information will enable the flightcrew to plan flight operations that
will maximize the maneuvering capability during high altitude cruise
flight and preclude intentional operations exceeding the boundary of
perceptible buffet. Buffeting is considered to be a warning to the
pilot that the airplane is approaching an undesirable and eventually
dangerous flight regime, that is, stall buffeting, high speed buffeting
or maneuvering (load factor) buffeting. In straight flight, therefore,
such buffet warning should not occur at any normal operating speed up
to the maximum operating limit speed, VMO/MMO.
[[Page 7953]]
High Speed Characteristics and Maximum Operating Limit Speed
The Sino Swearingen Model SJ30-2 will be operated at high altitude
and high speeds and the proposed operating envelope includes areas in
which Mach effects, which have not been considered in part 23, may be
significant. The anticipated low drag of the airplane and the proposed
operating envelope are representative of the conditions not envisioned
by the existing part 23 regulations. These conditions may degrade the
ability of the flightcrew to promptly recover from inadvertent
excursions beyond maximum operating speeds. The ability to pull a
positive load factor is needed to ensure, during recovery from upset,
that the airplane speed does not continue to increase to a value where
recovery may not be achievable by the average pilot or flightcrew.
Additionally, to allow the aircraft designer to conservatively
design to higher speeds than may be operationally required for the
airplane, the concept of VDF/MDF, the highest demonstrated
flight speed for the type design, is appropriate for this airplane.
This permits VD/MD the design dive speed, to be higher than
the speed actually required to be demonstrated in flight. Accordingly,
special conditions are proposed to allow determination of a maximum
demonstrated flight speed and to relate the determination of VMO/
MMO to the speed VDF/MDF.
Flight Flutter Tests
Flight flutter test special conditions are proposed to VDF/
MDF rather than to VD in keeping with the VDF/MDF
concept.
Out-of-Trim Characteristics
High speed airplanes have experienced a number of upset incidents
involving out-of-trim conditions. This is particularly true for swept-
wing airplanes and airplanes with a trimmable stabilizer. Service
experience has shown that out-of-trim conditions can occur in flight
for various reasons and that the control and maneuvering
characteristics of the airplane may be critical in recovering from
upsets. The existing part 23 regulations do not address high speed out-
of-trim conditions. Special conditions are proposed that test the out-
of-trim flight characteristics by requiring the longitudinal trim
control be displaced from the trimmed position by the amount resulting
from the three-second movement of the trim system at this normal rate
with no aerodynamic load, or the maximum mis-trim that the autopilot
can sustain in level flight in the high speed cruise condition,
whichever is greater. The proposal would require the maneuvering
characteristics, including stick force per g, be explored throughout a
specified maneuver load factor speed envelope. The dive recovery
characteristics of the aircraft in the out-of-trim condition specified
would be investigated to determine that safe recovery can be made from
the demonstrated flight dive speed VDF/MDF.
Pressure Vessel Integrity
Damage tolerance methods are proposed to be used to ensure pressure
vessel integrity while operating at the higher altitudes instead of the
1/2 bay crack criterion used in some previous special conditions. Crack
growth data are used to prescribe an inspection program that should
detect cracks before an opening in the pressure vessel would allow
rapid depressurization. Initial crack sizes for detection are
determined under Sec. 23.573. The cabin altitude after failure must not
exceed the cabin altitude/time curve limits shown in Figures 3 and 4.
Flight Control System Integrity
The Sino Swearingen Model SJ30-2 will be operated at high altitude
and speeds such that a reduction or loss of pitch, yaw, or roll control
capability or response could preclude continued flight and landing
within the design limitations of the airplane using normal pilot skill
and strength. Consequently, a greater reliability of the fasteners in
the flight control system is necessary than previously considered.
Removable fasteners whose loss could result in the conditions described
above are required to have dual locking devices.
Fuel System Protection During Collapse of Landing Gear
The SJ30-2 maximum fuel weight is 39 percent of the maximum weight.
This percentage is typical of the turbofan powered business jet class
of airplanes. Part 23 did not envision that the applicable airplane
designs would have such a large fraction of maximum weight as fuel.
Part 23 does not contain fuel system protection requirements during
landing gear collapse, except for Sec. 23.721, which pertains to
commuter category airplanes that have a passenger seating configuration
of 10 seats or more. In the SJ30-2 design, there is a large fuselage
fuel tank and the placement of the engines on the aft fuselage requires
that the fuel lines be routed through the fuselage, making the fuel
lines more vulnerable to damage, or rupture, if the landing gear
collapses. A special condition is proposed based on 14 CFR part 25,
Sec. 25.721(a)(1) that is applicable to airplanes having a passenger
seating configuration of nine seats, or fewer.
Oxygen System Equipment and Supply
Continuous flow passenger oxygen equipment is certified for use up
to 40,000 feet; however, for rapid decompressions above 34,000 feet,
reverse diffusion leads to low oxygen partial pressures in the lungs to
the extent that a small percentage of passengers may lose useful
consciousness at 35,000 feet even with the use of the continuous flow
system. To prevent permanent physiological damage, the cabin altitude
must not exceed 25,000 feet for more than 2 minutes. The maximum peak
cabin altitude of 40,000 feet is consistent with the standards
established for previous certification programs. In addition, at high
altitudes the other aspects of decompression sickness have a
significant detrimental effect on pilot performance (for example, a
pilot can be incapacitated by internal expanding gases).
Decompression above the 37,000 foot limit depicted in Figure 4
approaches the physiological limits of the average person; therefore,
every effort must be made to provide the pilots with adequate oxygen
equipment to withstand these severe decompressions. Reducing the time
interval between pressurization failure and the time the pilots receive
oxygen will provide a safety margin against being incapacitated and can
be accomplished by the use of mask-mounted regulators. The proposed
special condition, therefore, would require pressure demand masks with
mask-mounted regulators for the flightcrew. This combination of
equipment will provide the best practical protection for the failures
covered by this special conditions and for improbable failures not
covered by the special conditions, provided the cabin altitude is
limited.
Airspeed Indicating System
To maintain a level of safety consistent with that applied to
previous part 23 jet airplanes, and to be consistent with the
establishment of speed schedule performance requirements, it is
appropriate to establish applicable requirements for determining and
providing airspeed indicating system calibration information.
Additionally, it is appropriate to establish special conditions
requiring protection of the pitot tube from malfunctions associated
with icing conditions. Current standards
[[Page 7954]]
in part 23 did not envision this type of airplane and the associated
airspeed indicating system requirements. Special conditions are
proposed to establish airspeed indicating system calibration and pitot
tube ice protection requirements applicable to transport category jet
airplanes.
Static Pressure System
To maintain a level of safety consistent with that applied to
previous part 23 jet airplanes, and to be consistent with the
establishment of speed schedule performance requirements, it is
appropriate to establish applicable requirements for providing static
pressure system calibration information in the AFM. Since aircraft of
this type are frequently equipped with devices to correct the altimeter
indication, it is also appropriate to establish requirements to ensure
the continued availability of altitude information where such a device
malfunctions. Current standards in part 23 did not envision this type
of airplane and the associated static pressure requirements.
Minimum Flightcrew
The Sino Swearingen Model SJ30-2 operates at high altitudes and
speeds not envisioned in part 23 and must be flown in a precise speed
schedule to achieve flight manual takeoff and landing distances.
Therefore, it is appropriate to specify workload considerations.
Special conditions are proposed to specify the items to be considered
in workload determination.
Airplane Flight Manual (AFM) Information
To be consistent with the performance special conditions, it is
also necessary to require the maximum takeoff and landing weights,
takeoff distances, and associated atmospheric conditions be made
available to the pilot in the AFM and that the airplane be operated
within its performance capabilities. Special conditions are proposed to
add maximum takeoff weights, maximum landing weights, and minimum
takeoff distances as limitations in the AFM. Additionally, special
conditions are proposed to add takeoff flight path and procedures
necessary to achieve the performance in the limitations section as
information in the AFM.
Conclusion
In view of the design features discussed for the SJ30-2 Model
airplane, the following special conditions are proposed. This action is
not a rule of general applicability and affects only the model/series
of airplane identified in these final special conditions.
List of Subjects in 14 CFR Part 23
Aircraft, Aviation safety, Signs and symbols.
Citation
The authority citation for these Special Conditions is as follows:
Authority: 49 U.S.C. 106(g); 40113, and 44701; 14 CFR 21.16 and
101; and 14 CFR 11.28 and 11.29.
The Proposed Special Conditions
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes the
following special conditions as part of the type certification basis
for the Sino Swearingen Model SJ30-2 airplane:
1. Protection of Electrical and Electronic Systems From High Intensity
Radiated Field
Each system that performs critical functions must be designed and
installed to ensure that the operation and operational capabilities of
these systems to perform critical functions are not adversely affected
when the airplane is exposed to high intensity radiated fields external
to the airplane.
2. Performance: General
In addition to the requirements of Sec. 23.45, the following apply:
(a) Unless otherwise prescribed, the applicant must select the
takeoff, enroute, approach, and landing configurations for the
airplane.
(b) The airplane configurations may vary with weight, altitude, and
temperature, to the extent that they are compatible with the operating
procedures required by paragraph (c) of this special condition.
(c) Unless otherwise prescribed, in determining the accelerate-stop
distances, takeoff flight paths, takeoff distances, and landing
distances, changes in the airplane's configuration, speed, power, and
thrust, must be made in accordance with procedures established by the
applicant for operation in service.
(d) Procedures for the execution of balked landings and
discontinued approaches associated with the conditions prescribed in
special conditions 10(d) and 12 must be established.
(e) The procedures established under paragraphs (c) and (d) of this
special condition must:
(1) Be able to be consistently executed in service by crews of
average skill;
(2) Use methods or devices that are safe and reliable; and
(3) Include allowance for any time delays, in the execution of the
procedures, that may reasonably be expected in service.
3. Takeoff
Instead of complying with Sec. 23.53, the following apply:
(a) In special conditions 4, 5, 6, and 7, the takeoff speeds, the
accelerate-stop distance, the takeoff path, the takeoff distance, and
takeoff run described must be determined:
(1) At each weight, altitude, and ambient temperature within the
operation limits selected by the applicant; and
(2) In the selected configuration for takeoff.
(b) No takeoff made to determine the data required by this section
may require exceptional piloting skill or alertness.
(c) The takeoff data must be based on a smooth, dry, hard-surfaced
runway.
(d) The takeoff data must include, within the established
operational limits of the airplane, the following operational
correction factors:
(1) Not more than 50 percent of nominal wind components along the
takeoff path opposite to the direction of takeoff, and not less than
150 percent of nominal wind components along the takeoff path in the
direction of takeoff.
(2) Effective runway gradients.
4. Takeoff Speeds
Instead of compliance with Sec. 23.51, the following apply:
(a) V1 must be established in relation to VEF, as
follows:
(1) VEF is the calibrated airspeed at which the critical
engine is assumed to fail. VEF must be selected by the applicant,
but may not be less than VMCG determined under Sec. 23.149(f).
(2) V1, in terms of calibrated airspeed, is the takeoff
decision speed selected by the applicant; however, V1 may not be
less than VEF plus the speed gained with the critical engine
inoperative during the time interval between the instant at which the
critical engine failed and the instant at which the pilot recognizes
and reacts to the engine failure, as indicated by the pilot's
application of the first retarding means during the accelerate-stop
test.
(b) V2 min, in terms of calibrated airspeed, may not be less
than the following:
(1) 1.2 VS1
(2) 1.10 times VMC established under Sec. 23.149.
(c) V2, in terms of calibrated airspeed, must be selected by
the applicant to provide at least the gradient of climb required by
special condition 10,
[[Page 7955]]
paragraph (b), but may not be less than the following:
(1) V2 min, and
(2) VR plus the speed increment attained (in accordance with
special condition 6(c)(2)) before reaching a height of 35 feet above
the takeoff surface.
(d) VMU is the calibrated airspeed at and above which the
airplane can safely lift off the ground and continue the takeoff.
VMU speeds must be selected by the applicant throughout the range
of thrust-to-weight ratios to be certified. These speeds may be
established from free-air data if these data are verified by ground
takeoff tests.
(e) VR, in terms of calibrated airspeed, must be selected in
accordance with the following conditions of paragraphs (e)(1) through
(e)(4) of this special condition:
(1) VR may not be less than the following:
(i) V1;
(ii) 105 percent of VMC;
(iii) The speed (determined in accordance with special condition 6,
paragraph (c)(2)) that allows reaching V2 before reaching a height
of 35 feet above the takeoff surface; or
(iv) A speed that, if the airplane is rotated at its maximum
practicable rate, will result in a VLOF of not less than 110
percent of VMU in the all-engines-operating condition and not less
than 105 percent of VMU determined at the thrust-to-weight ratio
corresponding to the one-engine-inoperative condition.
(2) For any given set of conditions (such as weight, configuration,
and temperature), a single value of VR, obtained in accordance
with this special condition, must be used to show compliance with both
the one-engine-inoperative and the all-engines-operating takeoff
provisions.
(3) It must be shown that the one-engine-inoperative takeoff
distance, using a rotation speed of 5 knots less than VR,
established in accordance with paragraphs (e)(1) and (e)(2) of this
special condition, does not exceed the corresponding one-engine-
inoperative takeoff distance using the established VR. The takeoff
distances must be determined in accordance with special condition 7,
paragraph (a)(1).
(4) Reasonably expecting variations in service from the established
takeoff procedures for the operation of the airplane (such as over-
rotation of the airplane and out-of-trim conditions) may not result in
unsafe flight characteristics or in marked increases in the scheduled
takeoff distances established in accordance with special condition 7.
(f) VLOF is the calibrated airspeed at which the airplane
first becomes airborne.
5. Accelerate-Stop Distance
In the absence of specific accelerate-stop distance requirements,
the following apply:
(a) The accelerate-stop distance is the sum of the distances
necessary to--
(1) Accelerate the airplane from a standing start to VEF with
all engines operating;
(2) Accelerate the airplane from VEF to V1, assuming that
the critical engine fails at VEF; and
(3) Come to a full stop from the point at which V1 is reached
assuming that, in the case of engine failure, the pilot has decided to
stop as indicated by application of the first retarding means at the
speed V1.
(b) Means other than wheel brakes may be used to determine the
accelerate-stop distance if that means--
(1) Is safe and reliable;
(2) Is used so that consistent results can be expected under normal
operating conditions; and
(3) Is such that exceptional skill is not required to control the
airplane.
(c) The landing gear must remain extended throughout the
accelerate-stop distance.
6. Takeoff Path
In the absence of specific takeoff path requirements, the following
apply:
(a) The takeoff path extends from a standing start to a point in
the takeoff at which the airplane is 1,500 feet above the takeoff
surface, or at which the transition from the takeoff to the enroute
configuration is completed and a speed is reached at which compliance
with special condition 10, paragraph (c), is shown, whichever point is
higher. In addition the following apply:
(1) The takeoff path must be based on procedures prescribed in
special condition 2.
(2) The airplane must be accelerated on the ground to VEF, at
which point the critical engine must be made inoperative and remain
inoperative for the rest of the takeoff; and
(3) After reaching VEF, the airplane must be accelerated to
V2.
(b) During the acceleration to speed V2, the nose gear may be
raised off the ground at a speed not less than VR. However, landing
gear retraction may not begin until the airplane is airborne.
(c) During the takeoff path determination, in accordance with
paragraphs (a) and (b) of this special condition, the following apply:
(1) The slope of the airborne part of the takeoff path must be
positive at each point;
(2) The airplane must reach V2 before it is 35 feet above the
takeoff surface and must continue at a speed as close as practical to,
but not less than, V2 until it is 400 feet above the takeoff
surface;
(3) At each point along the takeoff path, starting at the point at
which the airplane reaches 400 feet above the takeoff surface, the
available gradient of climb may not be less than 1.2 percent;
(4) Except for gear retraction, the airplane configuration may not
be changed, and no change in power or thrust that requires action by
the pilot may be made, until the airplane is 400 feet above the takeoff
surface.
(d) The takeoff path must be determined by a continuous
demonstrated takeoff or by synthesis from segments. If the takeoff path
is determined by the segmental method, the following apply:
(1) The segments must be clearly defined and must be related to the
distinct changes in the configuration, speed, and power or thrust;
(2) The weight of the airplane, the configuration, and the power or
thrust must be constant throughout each segment and must correspond to
the most critical condition prevailing in the segment;
(3) The flight path must be based on the airplane's performance
without ground effect; and
(4) The takeoff path data must be checked by continuous
demonstrated takeoffs, up to the point at which the airplane is out of
ground effect and its speed is stabilized, to ensure that the path is
conservative relative to the continuous path.
Note: The airplane is considered to be out of the ground effect
when it reaches a height equal to its wing span.
7. Takeoff Distance and Takeoff Run
In the absence of specific takeoff distance and takeoff run
requirements, the following apply:
(a) Takeoff distance is the greater of the following:
(1) The horizontal distance along the takeoff path from the start
of the takeoff to the point at which the airplane is 35 feet above the
takeoff surface, determined under special condition 6; or
(2) 115 percent of the horizontal distance along the takeoff path,
with all engines operating, from the start of the takeoff to the point
at which the airplane is 35 feet above the takeoff surface, as
determined by a procedure consistent with special condition 6.
(b) If the takeoff distance includes a clear way, the takeoff run
is the greater of:
[[Page 7956]]
(1) The horizontal distance along the takeoff path from the start
of the takeoff to a point equidistant between the point at which
VLOF is reached and the point at which the airplane is 35 feet
above the takeoff surface, as determined under special condition 6; or
(2) 115 percent of the horizontal distance along the takeoff path,
with all engines operating, from the start of the takeoff to a point
equidistant between the point at which VLOF is reached and the
point at which the airplane is 35 feet above the takeoff surface,
determined by a procedure consistent with special condition 6.
8. Takeoff Flight Path
In the absence of specific takeoff flight path requirements, the
following apply:
(a) The takeoff flight path begins 35 feet above the takeoff
surface at the end of the takeoff distance determined in accordance
with special condition 7.
(b) The net takeoff flight path data must be determined so that
they represent the actual takeoff flight paths (determined in
accordance with special condition 6 and with paragraph (a) of this
special condition) reduced at each point by a gradient of climb equal
to 0.8 percent.
(c) The prescribed reduction in climb gradient may be applied as an
equivalent reduction in acceleration along that part of the takeoff
flight path at which the airplane is accelerated in level flight.
9. Climb: General
Instead of compliance with Sec. 23.63, the following applies:
Compliance with the requirements of special conditions 10 and 12 must
be shown at each weight, altitude, and ambient temperature within the
operational limits established for the airplane and with the most
unfavorable center of gravity for each configuration.
10. Climb: One Engine Inoperative
Instead of compliance with Sec. 23.67, the following apply:
(a) Takeoff; landing gear extended. In the critical takeoff
configuration existing along the flight path (between the points at
which the airplane reaches VLOF and at which the landing gear is
fully retracted) and in the configuration used in special condition 6
without ground effect, unless there is a more critical power operating
condition existing later along the flight path before the point at
which the landing gear is fully retracted, the steady gradient of climb
must be positive at VLOF and with the following:
(1) The critical engine inoperative and the remaining engines at
the power or thrust available when retraction of the landing gear
begins in accordance with special condition 6, and
(2) The weight equal to the weight existing when retraction of the
landing gear begins, determined under special condition 6.
(b) Takeoff; landing gear retracted. In the takeoff configuration
existing at the point of the flight path at which the landing gear is
fully retracted and in the configuration used in special condition 6,
without ground effect, the steady gradient of climb may not be less
than 2.4 percent at V2 and with the following:
(1) The critical engine inoperative, the remaining engines at the
takeoff power or thrust available at the time the landing gear is fully
retracted, determined under special condition 6 unless there is a more
critical power operating condition existing later along the flight path
but before the point where the airplane reaches a height of 400 feet
above the takeoff surface; and
(2) The weight equal to the weight existing when the airplane's
landing gear is fully retracted, determined under special condition 6.
(c) Final takeoff. In the enroute configuration at the end of the
takeoff path, determined in accordance with special condition 6, the
steady gradient of climb may not be less than 1.2 percent at not less
than 1.25 VS and with the following:
(1) The critical engine inoperative and the remaining engines at
the available maximum continuous power or thrust; and
(2) The weight equal to the weight existing at the end of the
takeoff path, determined under special condition 6.
(d) Approach. In the approach configuration corresponding to the
normal all-engines-operating procedure in which VS for this
configuration does not exceed 110 percent of the VS for the
related landing configuration, the steady gradient of climb may not be
less than 2.1 percent with the following:
(1) The critical engine inoperative, the remaining engine at the
available in-flight takeoff power or thrust;
(2) The maximum landing weight; and
(3) A climb speed established in connection with normal landing
procedures, but not exceeding 1.5 VS.
11. Landing
Instead of compliance with Sec. 23.75, the following apply:
(a) The horizontal distance necessary to land and to come to a
complete stop from a point 50 feet above the landing surface must be
determined (for each weight, altitude, temperature, and wind within the
operational limits established by the applicant for the airplane), as
follows:
(1) The airplane must be in the landing configuration.
(2) A steady approach at a gradient of descent not greater than 5.2
percent (3 degrees), with an airspeed of not less than VREF,
determined in accordance with Sec. 23.73(b), must be maintained down to
the 50-foot height.
(3) Changes in configuration, power or thrust, and speed, must be
made in accordance with the established procedures for service
operation.
(4) The landing must be made without excessive vertical
acceleration, tendency to bounce, nose over, ground loop, or porpoise.
(5) The landings may not require exceptional piloting skill or
alertness.
(6) It must be shown that a safe transition to the balked landing
conditions of special condition 12 can be made from the conditions that
exist at the 50-foot height.
(b) The landing distance must be determined on a level, smooth,
dry, hard-surfaced runway. In addition, the following apply:
(1) The brakes may not be used so as to cause excessive wear of
brakes or tires; and
(2) Means other than wheel brakes may be used if that means is as
follows:
(i) Is safe and reliable;
(ii) Is used so that consistent results can be expected in service;
and
(iii) Is such that exceptional skill is not required to control the
airplane.
(c) The landing distance data must include correction factors for
not more than 50 percent of the nominal wind components along the
landing path opposite to the direction of landing and not less than 150
percent of the nominal wind components along the landing path in the
direction of landing.
(d) If any device is used that depends on the operation of any
engine, and if the landing distance would be noticeably increased when
a landing is made with that engine inoperative, the landing distance
must be determined with that engine inoperative unless the use of
compensating means will result in a landing distance not more than that
with each engine operating.
12. Balked Landing
Instead of compliance with Sec. 23.77, the following apply:
In the landing configuration, the steady gradient of climb may not
be less than 3.2 percent with the following:
(a) The engines at the power or thrust that is available eight
seconds after initiation of movement of the power or thrust controls
from the minimum flight idle to the inflight takeoff position; and
(b) A climb speed of not more than VREF as defined in
Sec. 23.73(a).
[[Page 7957]]
13. Stall Speed
Instead of compliance with Sec. 23.49, the following apply:
(a) VS is the calibrated stalling speed, or the minimum steady
flight speed, in knots, at which the airplane is controllable, with--
(1) Zero thrust at the stalling speed, or, if the resultant thrust
has no appreciable effect on the stalling speed, with engines idling
and throttles closed;
(2) The weight used when VS is being used as a factor to
determine compliance with a required performance standard; and
(3) The most unfavorable center of gravity allowable.
(b) The stalling speed VS is the minimum speed obtained as
follows:
(1) Trim the airplane for straight flight at any speed not less
than 1.2 VS or more than 1.4 VS. At a speed sufficiently
above the stall speed to ensure steady conditions, apply the elevator
control at a rate so that the airplane speed reduction does not exceed
one knot per second.
(2) Meet the flight characteristics provisions of special condition
19.
14. Trim
Instead of compliance with Sec. 23.161, the following apply:
(a) General. Each airplane must meet the trim requirements of this
special condition after being trimmed, and without further pressure
upon or movement of the primary controls or their corresponding trim
controls by the pilot or the automatic pilot.
(b) Lateral and directional trim. The airplane must maintain
lateral and directional trim with the most adverse lateral displacement
of the center of gravity within the relevant operating limitations
during normally expected conditions of operation (including operation
at any speed from 1.4 VS1 to VMO/MMO.)
(c) Longitudinal trim. The airplane must maintain longitudinal trim
during the following:
(1) A climb with maximum continuous power at a speed not more than
1.4 VS1, with the landing gear retracted, and the flaps in the
following positions:
(i) Retracted, and
(ii) In the takeoff position.
(2) A power approach with a 3 degree angle of descent, the landing
gear extended, and with the following:
(i) The wing flaps retracted and at a speed of 1.4 VS1; and
(ii) The applicable airspeed and flap position used in showing
compliance with special condition 11.
(3) Level flight at any speed from 1.4 VS1 to VMO/
MMO with the landing gear and flaps retracted, and from 1.4
VS1 to VLE with the landing gear extended.
(d) Longitudinal, directional, and lateral trim. The airplane must
maintain longitudinal, directional, and lateral trim (for the lateral
trim, the angle of bank may not exceed five degrees) at 1.4 VS1
during climbing flight with the following:
(1) The critical engine inoperative;
(2) The remaining engine at maximum continuous power or thrust; and
(3) The landing gear and flaps retracted.
15. Static Longitudinal Stability
Instead of compliance with Sec. 23.173, the following apply:
Under the conditions specified in special condition 16, the
characteristics of the elevator control forces (including friction)
must be as follows:
(a) A pull must be required to obtain and maintain speeds below the
specified trim speed, and a push must be required to obtain and
maintain speeds above the specified trim speed. This must be shown at
any speed that can be obtained except speeds higher than the landing
gear or wing flap operating limit speeds or VFC/MFC,
whichever is appropriate, or lower than the minimum speed for steady
unstalled flight.
(b) The airspeed must return to within 10 percent of the original
trim speed for the climb, approach, and landing conditions specified in
special condition 16, paragraph (a), (c), and (d), and must return to
within 7.5 percent of the original trim speed for the cruising
condition specified in special condition 16, paragraph (b), when the
control force is slowly released from any speed within the range
specified in paragraph (a) of this special condition.
(c) The average gradient of the stable slope of the stick force
versus speed curve may not be less than 1 pound for each 6 knots.
(d) Within the free return speed range specified in paragraph (b)
of this special condition, it is permissible for the airplane, without
control forces, to stabilize on speeds above or below the desired trim
speeds if exceptional attention on the part of the pilot is not
required to return to and maintain the desired trim speed and altitude.
16. Demonstration of Static Longitudinal Stability
Instead of compliance with Sec. 23.175, static longitudinal
stability must be shown as follows:
(a) Climb. The stick force curve must have a stable slope at speeds
between 85 and 115 percent of the speed at which the airplane--
(1) Is trimmed, with--
(i) Wing flaps retracted;
(ii) Landing gear retracted;
(iii) Maximum takeoff weight; and
(iv) The maximum power or thrust selected by the applicant as an
operating limitation for use during climb; and
(2) Is trimmed at the speed for best rate of climb except that the
speed need not be less than 1.4 VS1.
(b) Cruise. Static longitudinal stability must be shown in the
cruise condition as follows:
(1) With the landing gear retracted at high speed, the stick force
curve must have a stable slope at all speeds within a range which is
the greater of 15 percent of the trim speed plus the resulting free
return speed range, or 50 knots plus the resulting free return speed
range, above and below the trim speed (except that the speed range need
not include speeds less than 1.4 VS1, nor speeds greater than
VFC/MFC, nor speeds that require a stick force of more than
50 pounds), with--
(i) The wing flaps retracted;
(ii) The center of gravity in the most adverse position;
(iii) The most critical weight between the maximum takeoff and
maximum landing weights;
(iv) The maximum cruising power selected by the applicant as an
operating limitation, except that the power need not exceed that
required at VMO/MMO; and
(v) The airplane trimmed for level flight with the power required
in paragraph (b)(1)(iv) of this special condition.
(2) With the landing gear retracted at low speed, the stick force
curve must have a stable slope at all speeds within a range which is
the greater of 15 percent of the trim speed plus the resulting free
return speed range, or 50 knots plus the resulting free return speed
range, above and below the trim speed (except that the speed range need
not include speeds less than 1.4 VS1, nor speeds greater than the
minimum speed of the applicable speed range prescribed in paragraph
(b)(1), nor speeds that require a stick force of more than 50 pounds),
with--
(i) Wing flaps, center of gravity position, and weight as specified
in paragraph (b)(1) of this special condition;
(ii) Power required for level flight at a speed equal to (VMO
+ 1.4 VS1)/2; and
(iii) The airplane trimmed for level flight with the power required
in paragraph (b)(2)(ii) of this special condition.
(3) With the landing gear extended, the stick force curve must have
a stable slope at all speeds within a range which
[[Page 7958]]
is the greater of 15 percent of the trim speed plus the resulting free
return speed range, or 50 knots plus the resulting free return speed
range, above and below the trim speed (except that the speed range need
not include speeds less than 1.4 VS1, nor speeds greater than
VLE, nor speeds that require a stick force of more than 50
pounds), with--
(i) Wing flap, center of gravity position, and weight as specified
in paragraph (b)(1) of this section;
(ii) The maximum cruising power selected by the applicant as an
operating limitation, except that the power need not exceed that
required for level flight at VLE; and
(iii) The aircraft trimmed for level flight with the power required
in paragraph (b)(3)(ii) of this section.
(c) Approach. The stick force curve must have a stable slope at
speeds between 1.1 VS1 and 1.8 VS1, with--
(1) Wing flaps in the approach position;
(2) Landing gear retracted;
(3) Maximum landing weight; and
(4) The airplane trimmed at 1.4 VS1 with enough power to
maintain level flight at this speed.
(d) Landing. The stick force curve must have a stable slope, and
the stick force may not exceed 80 pounds, at speeds between 1.1
VS0 and 1.3 VS0 with--
(1) Wing flaps in the landing position;
(2) Landing gear extended;
(3) Maximum landing weight;
(4) Power or thrust off on the engines; and
(5) The airplane trimmed at 1.4 VS0 with power or thrust off.
17. Static Directional and Lateral Stability
Instead of compliance with Sec. 23.177, the following apply:
(a) The static directional stability (as shown by the tendency to
recover from a skid with the rudder free) must be positive for any
landing gear and flap position, and it must be positive for any
symmetrical power condition to speeds from 1.2 VS1 up to VFE,
VLE, or VFC/MFC (as appropriate).
(b) The static lateral stability (as shown by the tendency to raise
the low wing in a sideslip with the aileron controls free and for any
landing gear position and flap position, and for any symmetrical power
conditions) may not be negative at any airspeed (except speeds higher
than VFE or VLE, when appropriate) in the following airspeed
ranges:
(1) From 1.2 VS1 to VMO/MMO.
(2) From VMO/MMO to VFC/MFC, unless the
Administrator finds that the divergence is--
(i) Gradual;
(ii) Easily recognizable by the pilot; and
(iii) Easily controllable by the pilot.
(c) In straight, steady, sideslips (unaccelerated forward slips)
the aileron and rudder control movement and forces must be
substantially proportional to the angle of the sideslip. The factor of
proportionality must lie between limits found necessary for safe
operation throughout the range of sideslip angles appropriate to the
operation of the airplane. At greater angles, up to the angle at which
full rudder control is used or when a rudder pedal force of 180 pounds
is obtained, the rudder pedal forces may not reverse and increased
rudder deflection must produce increased angles of sideslip. Unless the
airplane has a yaw indicator, there must be enough bank accompanying
sideslipping to clearly indicate any departure from steady unyawed
flight.
18. Stall Demonstration
Instead of compliance with Sec. 23.201, the following apply:
(a) Stalls must be shown in straight flight and in 30 degree banked
turns with--
(1) Power off; and
(2) The power necessary to maintain level flight at 1.6 VS1
(where VS1 corresponds to the stalling speed with flaps in the
approach position, the landing gear retracted, and maximum landing
weight).
(b) In each condition required by paragraph (a) of this section, it
must be possible to meet the applicable requirements of special
condition 19 with--
(1) Flaps, landing gear, and deceleration devices in any likely
combination of positions approved for operation;
(2) Representative weights within the range for which certification
is requested;
(3) The most adverse center of gravity for recovery; and
(4) The airplane trimmed for straight flight at the speed
prescribed in special condition 13).
(c) The following procedures must be used to show compliance with
special condition 19;
(1) Starting at a speed sufficiently above the stalling speed to
ensure that a steady rate of speed reduction can be established, apply
the longitudinal control so that the speed reduction does not exceed
one knot per second until the airplane is stalled.
(2) In addition, for turning flight stalls, apply the longitudinal
control to achieve airspeed deceleration rates up to 3 knots per
second.
(3) As soon as the airplane is stalled, recover by normal recovery
techniques.
(d) The airplane is considered stalled when the behavior of the
airplane gives the pilot a clear and distinctive indication of an
acceptable nature that the airplane is stalled. Acceptable indications
of a stall, occurring either individually or in combination, are--
(1) A nose-down pitch that cannot be readily arrested;
(2) Buffeting, of a magnitude and severity that is a strong and
effective deterrent to further speed reduction; or
(3) The pitch control reaches the aft stop and no further increase
in pitch attitude occurs when the control is held full aft for a short
time before recovery is initiated.
19. Stall Characteristics
Instead of compliance with Sec. 23.203, the following applies:
(a) It must be possible to produce and to correct roll and yaw by
unreversed use of the aileron and rudder controls, up to the time the
airplane is stalled. No abnormal nose up pitching may occur. The
longitudinal control force must be positive up to and throughout the
stall. In addition, it must be possible to promptly prevent stalling
and to recover from a stall by normal use of the controls.
(b) For level wing stalls, the roll occurring between the stall and
the completion of the recovery may not exceed approximately 20 degrees.
(c) For turning flight stalls, the action of the airplane after the
stall may not be so violent or extreme as to make it difficult, with
normal piloting skill, to effect a prompt recovery and to regain
control of the airplane. The maximum bank angle that occurs during the
recovery may not exceed--
(1) Approximately 60 degrees in the original direction of the turn,
or 30 degrees in the opposite direction, for deceleration rates up to 1
knot per second; and
(2) Approximately 90 degrees in the original direction of the turn,
or 60 degrees in the opposite direction, for deceleration rates in
excess of 1 knot per second.
20. Stall Warning
Instead of compliance with Sec. 23.207, the following applies:
(a) Stall warning with sufficient margin to prevent inadvertent
stalling with the flaps and landing gear in any normal position must be
clear and distinctive to the pilot in straight and turning flight.
(b) The warning may be furnished either through the inherent
aerodynamic qualities of the airplane or by a device
[[Page 7959]]
that will give clearly distinguishable indications under expected
conditions of flight. However, a visual stall warning device that
requires the attention of the crew within the cockpit is not acceptable
by itself. If a warning device is used, it must provide a warning in
each of the airplane configurations prescribed in paragraph (a) of this
special condition at the speed prescribed in paragraph (c) of this
special condition.
(c) The stall warning must begin at a speed exceeding the stalling
speed (i.e., the speed at which the airplane stalls or the minimum
speed demonstrated, whichever is applicable under the provisions of
special condition 18, paragraph (d)) by seven percent or at any lesser
margin if the stall warning has enough clarity, duration,
distinctiveness, or similar properties.
21. Vibration and Buffeting
Instead of compliance with Sec. 23.251, the following apply:
(a) The airplane must be designed to withstand any vibration and
buffeting that might occur in any likely operating condition. This must
be shown by calculations, resonance tests, or other tests found
necessary by the Administrator.
(b) Each part of the airplane must be shown in flight to be free
from excessive vibration, under any appropriate speed and power
conditions up to VDF/MDF. The maximum speeds shown must be
used in establishing the operating limitations of the airplane in
accordance with special condition 36.
(c) Except as provided in paragraph (d) of this special condition,
there may be no buffeting condition in normal flight, including
configuration changes during cruise, severe enough to interfere with
the control of the airplane, to cause excessive fatigue to the
flightcrew, or to cause structural damage. Stall warning buffeting
within these limits is allowable.
(d) There may be no perceptible buffeting condition in the cruise
configuration in straight flight at any speed up to VMO/MMO,
except that stall warning buffeting is allowable.
(e) With the airplane in the cruise configuration, the positive
maneuvering load factors at which the onset of perceptible buffeting
occurs must be determined for the ranges of airspeed or Mach Number,
weight, and altitude for which the airplane is to be certified. The
envelopes of load factor, speed, altitude, and weight must provide a
sufficient range of speeds and load factors for normal operations.
Probable inadvertent excursions beyond the boundaries of the buffet
onset envelopes may not result in unsafe conditions.
22. High Speed Characteristics
Instead of compliance with Sec. 23.253, the following apply:
(a) Speed increase and recovery characteristics. The following
speed increase and recovery characteristics must be met:
(1) Operating conditions and characteristics likely to cause
inadvertent speed increases (including upsets in pitch and roll) must
be simulated with the airplane trimmed at any likely cruise speed up to
VMO/MMO. These conditions and characteristics include gust
upsets, inadvertent control movements, low stick force gradient in
relation to control friction, passenger movement, leveling off from
climb, and descent from mach to airspeed limit altitudes.
(2) Allowing for pilot reaction time after effective inherent or
artificial speed warning occurs, it must be shown that the airplane can
be recovered to a normal attitude and its speed reduced to VMO/
MMO without the following:
(i) Exceptional piloting strength or skill;
(ii) Exceeding VD/MD, or VDF/MDF, or the
structural limitations; and
(iii) Buffeting that would impair the pilot's ability to read the
instruments or control the airplane for recovery.
(3) There may be no control reversal about any axis at any speed up
to VDF/MDF with the airplane trimmed at VMO/MMO.
Any tendency of the airplane to pitch, roll or yaw must be mild and
readily controllable, using normal piloting techniques. When the
airplane is trimmed at VMO/MMO, the slope of the elevator
control force versus speed curve need not be stable at speeds greater
than VFC/MFC, but there must be a push force at all speeds up
to VDF/MDF and there must be no sudden or excessive reduction
of elevator control force as VDF/MDF is reached.
(b) Maximum speed for stability characteristics. VFC/
MFC.. VFC/MFC is the maximum speed at which the
requirements of special conditions 15, 16, 17, and Sec. 23.181 must be
met with the flaps and landing gear retracted. It may not be less than
a speed midway between VMO/MMO and VDF/MDF except
that, for altitudes where Mach number is the limiting factor, MFC
need not exceed the Mach number at which effective speed warning
occurs.
23. Flight Flutter Testing
Instead of the term/speed VD in Sec. 23.629(b), use VDF/
MDF.
24. Out-of-Trim Characteristics
In the absence of specific requirements for out-of-trim
characteristics, the Sino Swearingen Model SJ30-2 must comply with the
following:
(a) From an initial condition with the airplane trimmed at cruise
speeds up to VMO/MMO, the airplane must have satisfactory
maneuvering stability and controllability with the degree of out-of-
trim in both the airplane nose-up and nose-down directions, which
results from the greater of the following:
(1) A three-second movement of the longitudinal trim system at its
normal rate for the particular flight condition with no aerodynamic
load (or an equivalent degree of trim for airplanes that do not have a
power-operated trim system), except as limited by stops in the trim
system including those required by Sec. 23.655(b) for adjustable
stabilizers; or
(2) The maximum mis-trim that can be sustained by the autopilot
while maintaining level flight in the high speed cruising condition.
(b) In the out-of-trim condition specified in paragraph (a) of this
special condition, when the normal acceleration is varied from +1 g to
the positive and negative values specified in paragraph (c) of this
special condition, the following apply:
(1) The stick force versus g curve must have a positive slope at
any speed up to and including VFC/MFC; and
(2) At speeds between VFC/MFC and VDF/MDF, the
direction of the primary longitudinal control force may not reverse.
(c) Except as provided in paragraph (d) and (e) of this special
condition, compliance with the provisions of paragraph (a) of this
special condition must be demonstrated in flight over the acceleration
range as follows:
(1) -1 g to +2.5 g; or
(2) 0 g to 2.0 g, and extrapolating by an acceptable method to -1 g
and +2.5 g.
(d) If the procedure set forth in paragraph (c)(2) of this special
condition is used to demonstrate compliance and marginal conditions
exist during flight test with regard to reversal of primary
longitudinal control force, flight tests must be accomplished from the
normal acceleration at which a marginal condition is found to exist to
the applicable limit specified in paragraph (b)(1) of this special
condition.
(e) During flight tests required by paragraph (a) of this special
condition, the limit maneuvering load factors, prescribed in
Secs. 23.333(b) and 23.337, need not be exceeded. Also, the
[[Page 7960]]
maneuvering load factors associated with probable inadvertent
excursions beyond the boundaries of the buffet onset envelopes
determined under special condition 21, paragraph (e), need not be
exceeded. In addition, the entry speeds for flight test demonstrations
at normal acceleration values less than 1 g must be limited to the
extent necessary to accomplish a recovery without exceeding VDF/
MDF.
(f) In the out-of-trim condition specified in paragraph (a) of this
special condition, it must be possible from an overspeed condition at
VDF/MDF to produce at least 1.5 g for recovery by applying
not more than 125 pounds of longitudinal control force using either the
primary longitudinal control alone or the primary longitudinal control
and the longitudinal trim system. If the longitudinal trim is used to
assist in producing the required load factor, it must be shown at
VDF/MDF that the longitudinal trim can be actuated in the
airplane nose-up direction with the primary surface loaded to
correspond to the least of the following airplane nose-up control
forces:
(1) The maximum control forces expected in service, as specified in
Secs. 23.301 and 23.397.
(2) The control force required to produce 1.5 g.
(3) The control force corresponding to buffeting or other phenomena
of such intensity that is a strong deterrent to further application of
primary longitudinal control force.
25. Pressure Vessel Integrity
(a) The maximum extent of failure and pressure vessel opening that
can be demonstrated to comply with special condition 31
(Pressurization) of these special conditions must be determined. It
must be demonstrated by crack propagation and damage tolerance analysis
supported by testing that a larger opening or a more severe failure
than demonstrated will not occur in normal operations.
(b) Inspection schedules and procedures must be established to
ensure that cracks and normal fuselage leak rates will not deteriorate
to the extent that an unsafe condition could exist during normal
operation.
(c) With regard to the fuselage structure design for cabin pressure
capability above 45,000 feet, the pressure vessel structure, including
doors and windows, must comply with Sec. 23.365(d), using a factor of
1.67 instead of the 1.33 factor prescribed.
26. Fasteners
In addition to the requirements of Sec. 23.607, the following apply
to fasteners:
(a) Each removable bolt, screw, nut, pin, or their removable
fastener must incorporate two separate locking devices if the following
apply:
(1) Its loss could preclude continued flight and landing within the
design limitations of the airplane using normal pilot skill and
strength, or
(2) Its loss could result in reduction in pitch, yaw, or roll
control capability or response below that required by subpart B of this
chapter and these special conditions.
(b) The fasteners specified in paragraph (a) of this section and
their locking devices may not be adversely affected by the
environmental conditions associated with the particular installation.
27. Landing Gear
The main landing gear system must be designed so that if it fails
due to overloads during takeoff or landing (assuming the overloads to
act in the upward and aft directions), the failure mode is not likely
to cause the spillage of enough fuel from any fuel system in the
fuselage to constitute a fire hazard.
28. Ventilation
In addition to the requirements of Sec. 23.831(b), the ventilation
system must be designed to provide a sufficient amount of
uncontaminated air to enable the crewmembers to perform their duties
without undue discomfort or fatigue and to provide reasonable passenger
comfort during normal operation conditions and in the event of any
probable failure of any system on the airplane that would adversely
affect the cabin ventilating air. For normal operations, crewmembers
and passengers must be provided with at least 10 cubic feet of fresh
air per minute per person, or the equivalent in filtered recirculated
air, based on the volume and composition at the corresponding cabin
pressure altitude of no more than 8,000 feet.
29. Air Conditioning
In addition to the requirements of Sec. 23.831, cabin cooling
systems must be designed to meet the following conditions during flight
above 15,000 feet MSL:
(a) After any probable failure, the cabin temperature/time history
may not exceed the values shown in Figure 1. During this time period,
the humidity shall never exceed a level that corresponds to a water
vapor pressure of 20mm Hg. Time = 0 minutes when the flightcrew
recognizes the failure.
(b) After any improbable failure, the cabin temperature/time
history may not exceed the values shown in Figure 2. During this time
period, the humidity shall never exceed a level that corresponds to a
water vapor pressure of 20mm Hg. Time = 0 minutes when the flightcrew
recognizes the failure.
30. Pressurization
In addition to the requirements of Sec. 23.841, the following
apply--
(a) The pressurization system--which includes, for this purpose,
bleed air, air conditioning, and pressure control systems--must prevent
the cabin altitude from exceeding the cabin altitude-time history shown
in Figure 3 after each of the following:
(1) Any probable malfunction or failure of the pressurization
system. The existence of undetected, latent malfunctions or failures in
conjunction with probable failures must be considered.
(2) Any single failure in the pressurization system, combined with
the occurrence of a leak produced by a complete loss of a door seal
element, or a fuselage leak through an opening having an effective area
2.0 times the effective area that produces the maximum permissible
fuselage leak rate approved for normal operation, whichever produces a
more severe leak.
(b) The cabin altitude-time history may not exceed that shown in
Figure 4 after each of the following:
(1) The maximum pressure vessel opening resulting from an initially
detectable crack propagating for a period encompassing four normal
inspection intervals. Mid-panel cracks and cracks through skin-stringer
and skin-frame combinations must be considered.
(2) The pressure vessel opening or duct failure resulting from
probable damage (failure effect) while under maximum operating cabin
pressure differential due to a tire burst, engine rotor burst, loss of
antennas or stall warning vanes, or any probable equipment failure
(bleed air, pressure control, air conditioning, electrical sources(s),
etc.) that affects pressurization.
(3) Complete loss of thrust from all engines.
(c) In showing compliance with paragraphs (a) and (b) of this
special condition (Pressurization), it may be assumed that an emergency
descent is made by approved emergency procedure. A seventeen-second
flightcrew recognition and reaction time must be applied between cabin
altitude
[[Page 7961]]
warning and the initiation of an emergency descent.
Note: For the flight evaluation of the rapid descent, the test
article must have the cabin volume representative of what is
expected to be normal, such that Sino Swearingen must reduce the
total cabin volume by that which would be occupied by the
furnishings and total number of people.
31. Airspeed Indicating System
In addition to the requirements of Sec. 23.1323, the following
apply:
(a) The airspeed indicating system must be calibrated to determine
the system error in flight and during the accelerate-takeoff ground
run. The ground run calibration must be determined as follows:
(1) From 0.8 of the minimum value of V1 to the maximum value
of V2, considering the approved ranges of altitude and weight; and
(2) With the flaps and power settings corresponding to the values
determined in the establishment of the takeoff path under special
condition 6, assuming that the critical engine fails at the minimum
value of V1.
(b) The information showing the relationship between IAS and CAS,
determined in accordance with paragraph (a) of this special condition,
must be shown in the Airplane Flight Manual.
32. Static Pressure System
In addition to the requirements of Sec. 23.1325, the following
apply:
(a) The altimeter system calibration required by Sec. 23.1325(e)
must be shown in the Airplane Flight Manual.
(b) If an altimeter system is fitted with a device that provides
corrections to the altimeter indication, the device must be designed
and installed in such manner that it can be by-passed when it
malfunctions, unless an alternate altimeter system is provided. Each
correction device must be fitted with a means for indicating the
occurrence of reasonably probable malfunctions, including power
failure, to the flightcrew. The indicating means must be effective for
any cockpit lighting condition likely to occur.
33. Oxygen Equipment and Supply
(a) In addition to the requirements of Sec. 23.1441(d), the
following applies: A quick-donning oxygen mask system with a pressure-
demand, mask mounted regulator must be provided for the flightcrew. It
must be shown that each quick-donning mask can, with one hand and
within 5 seconds, be placed on the face from its ready position,
properly secured, sealed, and supplying oxygen upon demand.
(b) In addition to the requirements of Sec. 23.1443, the following
applies: A continuous flow oxygen system must be provided for the
passengers.
(c) In addition to the requirements of Sec. 23.1445, the following
applies: If the flightcrew and passengers share a common source of
oxygen, a means to separately reserve the minimum supply required by
the flightcrew must be provided.
34. Maximum Operating Limit Speed
Instead of compliance with Sec. 23.1505(c), the following applies:
The maximum operating limit speed (VMO/MMO airspeed or Mach
number, whichever is critical at a particular altitude) is a speed that
may not be deliberately exceeded in any regime of flight (climb,
cruise, or descent), unless a higher speed is authorized for flight
test or pilot training operations. VMO/MMO must be
established so that it is not greater than the design cruising speed,
VC, and so that it is sufficiently below VD/MD, or
VDF/MDF, to make it highly improbable that the latter speeds
will be inadvertently exceeded in operations. The speed margin between
VMO/MMO and VD/MD, or VDF/MDF, may not be
less than that determined under Sec. 23.335(b) or found necessary
during the flight tests conducted under special condition 22.
35. Minimum Flightcrew
Instead of compliance with Sec. 23.1523, the following apply:
The minimum flightcrew must be established so that it is sufficient
for safe operation considering:
(a) The workload on individual flightcrew members and each
flightcrew member workload determination must consider the following:
(1) Flight path control,
(2) Collision avoidance,
(3) Navigation,
(4) Communications,
(5) Operation and monitoring of all essential airplane systems,
(6) Command decisions, and
(7) The accessibility and ease of operation of necessary controls by
the appropriate flightcrew member during all normal and emergency
operations when at the flightcrew member station.
(b) The accessibility and ease of operation of necessary controls
by the appropriate flightcrew member; and
(c) The kinds of operation authorized under Sec. 23.1525.
36. Airplane Flight Manual
Instead of compliance with Sec. 23.1581, the following applies:
(a) Furnishing information. An Airplane Flight Manual must be
furnished with each airplane, and it must contain the following:
(1) Information required by special conditions 39, 40, and 41.
(2) Other information that is necessary for safe operation because
of design, operating, or handling characteristics.
(3) Any limitation, procedure, or other information established as
a condition of compliance with the applicable noise standards of Part
36 of this chapter.
(b) Approved Information. Each part of the manual listed in special
conditions 39, 40, and 41, that is appropriate to the airplane, must be
furnished, verified, and approved, and must be segregated, identified,
and clearly distinguished from each unapproved part of that manual.
(c) Airplane Flight Manual. Each Airplane Flight Manual must
include a table of contents if the complexity of the manual indicates a
need for it.
(d) Airplane Flight Manual. Each page of the Airplane Flight Manual
containing information prescribed in this section must be of a type
that is not easily erased, disfigured, or misplaced, and is capable of
being inserted in a manual provided by the applicant, or in a folder,
or in any other permanent binder.
(e) Airplane Flight Manual. Provision must be made for stowing the
Airplane Flight Manual in a suitable fixed container which is readily
accessible to the pilot.
(f) Revisions and amendments. Each Airplane Flight Manual (AFM)
must contain a means for recording the incorporation of revisions and
amendments.
37. Operating Limitations
Instead of the requirements of Sec. 23.1583, the following apply:
(a) Airspeed limitations. The following airspeed limitations and
any other airspeed limitations necessary for safe operation must be
furnished:
(1) The maximum operating limit speed, VMO/MMO, and a
statement that this speed limit may not be deliberately exceeded in any
regime of flight (climb, cruise, or descent) unless a higher speed is
authorized for flight test or pilot training.
(2) If an airspeed limitation is based upon compressibility
effects, a statement to this effect and information as to any symptoms,
the probable behavior of the airplane, and the recommended recovery
procedures.
(3) The maneuvering speed, VO, and a statement that full
application of rudder and aileron controls, as well as maneuvers that
involve angles of attack
[[Page 7962]]
near the stall, should be confined to speeds below this value.
(4) The maximum speed for flap extension, VFE, for the
takeoff, approach, and landing positions.
(5) The landing gear operating speed or speeds, VLO.
(6) The landing gear extended speed, VLE if greater than
VLO, and a statement that this is the maximum speed at which the
airplane can be safely flown with the landing gear extended.
(b) Powerplant limitations. The following information must be
furnished:
(1) Limitations required by Sec. 23.1521.
(2) Explanation of the limitations, when appropriate.
(3) Information necessary for marking the instruments, required by
Secs. 23.1549 through 23.1553.
(c) Weight and loading distribution. The weight and extreme forward
and aft center of gravity limits required by Secs. 23.23 and 23.25 must
be furnished in the Airplane Flight Manual. In addition, all of the
following information and the information required by Sec. 23.1589 must
be presented either in the Airplane Flight Manual or in a separate
weight and balance control and loading document, which is incorporated
by reference in the Airplane Flight Manual:
(1) The condition of the airplane and the items included in the
empty weight, as defined in accordance with Sec. 23.29.
(2) Loading instructions necessary to ensure loading of the
airplane within the weight and center of gravity limits, and to
maintain the loading within these limits in flight.
(d) Maneuvers. A statement that acrobatic maneuvers, including
spins, are not authorized.
(e) Maneuvering flight load factors. The positive maneuvering limit
load factors for which the structure is proven, described in terms of
accelerations, and a statement that these accelerations limit the angle
of bank in turns and limit the severity of pull-up maneuvers must be
furnished.
(f) Flightcrew. The number and functions of the minimum flightcrew
must be furnished.
(g) Kinds of operation. The kinds of operation (such as VFR, IFR,
day, or night) and the meteorological conditions in which the airplane
may or may not be used must be furnished. Any installed equipment that
affects any operating limitation must be listed and identified as to
operational function.
(h) Additional operating limitations must be established as
follows:
(1) The maximum takeoff weights must be established as the weights
at which compliance is shown with the applicable provisions of part 23
(including the takeoff climb provisions of special condition 10 (a)
through (c) for altitudes and ambient temperatures).
(2) The maximum landing weights must be established as the weights
at which compliance is shown with the applicable provisions of part 23
(including the approach climb and balked landing climb provisions of
special conditions 10(d) and 12 for altitudes and ambient
temperatures).
(3) The minimum takeoff distances must be established as the
distances at which compliance is shown with the applicable provisions
of part 23 (including the provisions of special conditions 5 and 7 for
weights, altitudes, temperatures, wind components, and runway
gradients).
(4) The extremes for variable factors (such as altitude,
temperature, wind, and runway gradients) are those at which compliance
with the applicable provision of part 23 and these special conditions
is shown.
(i) Maximum operating altitude. The maximum altitude established
under Sec. 23.1527 must be furnished.
(j) Maximum passenger seating configuration. The maximum passenger
seating configuration must be furnished.
38. Operating Procedures
Instead of the requirements of Sec. 23.1585, the following applies:
(a) Information and instruction regarding the peculiarities of
normal operations (including starting and warming the engines, taxiing,
operation of wing flaps, slats, landing gear, speed brake, and the
automatic pilot) must be furnished, together with recommended
procedures for the following:
(1) Engine failure (including minimum speeds, trim, operation of
the remaining engine, and operation of flaps);
(2) Restarting turbine engines in flight (including the effects of
altitude);
(3) Fire, decompression, and similar emergencies;
(4) Use of ice protection equipment;
(5) Operation in turbulence (including recommended turbulence
penetration airspeeds, flight peculiarities, and special control
instructions);
(6) The demonstrated crosswind velocity and procedures and
information pertinent to operation of the airplane in crosswinds.
(b) Information identifying each operating condition in which the
fuel system independence prescribed in Sec. 23.953 is necessary for
safety must be furnished, together with instructions for placing the
fuel system in a configuration used to show compliance with that
section.
(c) For each airplane showing compliance with Sec. 23.1353(g)(2) or
(g)(3), the operating procedures for disconnecting the battery from its
charging source must be furnished.
(d) If the unusable fuel supply in any tank exceeds 5 percent of
the tank capacity, or 1 gallon, whichever is greater, information must
be furnished indicating that, when the fuel quantity indicator reads
``zero'' in level flight, any fuel remaining in the fuel tank cannot be
used safely in flight.
(e) Information on the total quantity of usable fuel for each fuel
tank must be furnished.
(f) The buffet onset envelopes determined under special condition
21 must be furnished. The buffet onset envelopes presented may reflect
the center of gravity at which the airplane is normally loaded during
cruise if corrections for the effect of different center of gravity
locations are furnished.
39. Performance Information
Instead of the requirements of Sec. 23.1587, the following applies:
(a) Each Airplane Flight Manual must contain information to permit
conversion of the indicated temperature to free air temperature if
other than a free air temperature indicator is used to comply with the
requirements of Sec. 23.1303(d).
(b) Each Airplane Flight Manual must contain the performance
information computed under the applicable provisions of this part for
the weights, altitudes, temperatures, wind components, and runway
gradients, as applicable, within the operational limits of the
airplane, and must contain the following:
(1) The conditions under which the performance information was
obtained, including the speeds associated with the performance
information.
(2) VS determined in accordance with special condition 13.
(3) The following performance information (determined by
extrapolation and computed for the range of weights between the maximum
landing and maximum takeoff weights):
(i) Climb in the landing configuration.
(ii) Climb in the approach configuration.
(iii) Landing distance.
(4) Procedures established under special condition 2, paragraph
(c), (d), and (e) that are related to the limitations and information
required by paragraph (h) of special condition 39 and by this
paragraph. These procedures must be in the form of guidance material,
including any relevant limitations or information.
(5) An explanation of significant or unusual flight or ground
handling characteristics of the airplane.
[[Page 7963]]
Issued in Kansas City, Missouri on February 10, 1997.
Henry A. Armstrong,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
BILLING CODE 4910-13-P
[GRAPHIC] [TIFF OMITTED] TP21FE97.011
[[Page 7964]]
[GRAPHIC] [TIFF OMITTED] TP21FE97.012
[FR Doc. 97-4353 Filed 2-20-97; 8:45 am]
BILLING CODE 4910-13-C