[Federal Register Volume 63, Number 211 (Monday, November 2, 1998)]
[Proposed Rules]
[Pages 58660-58671]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-29301]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE145, Notice No. 23-98-01-SC]


Special Conditions; Raytheon Model 390 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 Raytheon 
Aircraft Company Model 390 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 turbofan engines, engine location, swept wings and 
stabilizer, and certain performance characteristics necessary for this 
type of airplane, for which the applicable regulations do not contain 
adequate or appropriate airworthiness standards. This notice contains 
the additional airworthiness standards that the Administrator considers 
necessary to establish a level of safety equivalent to that existing in 
the current business jet fleet and expected by the user of this class 
of aircraft.

DATES: Comments must be received on or before December 2, 1998.

ADDRESSES: Comments on this proposal may be mailed in duplicate to: 
Federal Aviation Administration, Regional Counsel, ACE-7, Attention: 
Rules Docket Clerk, Docket No. CE145, Room No. 1558, 601 East 12th 
Street, Kansas City, Missouri 64106. All comments must be marked: 
Docket No. CE145. 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. CE145.'' 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 August 1, 1995, Raytheon Aircraft Company (then Beech Aircraft 
Corporation), 9707 East Central, Wichita, Kansas 67201, made 
application for 14 CFR part 23 normal category type certification of 
its Model 390 airplane. The Model 390 has a composite fuselage, a metal 
wing with 22.8 degrees of leading-edge sweepback, and a combination 
composite/metal empennage in a T-tail configuration with trimmable 
horizontal tail with 27.3 degrees of leading-edge sweepback. The 
airplane will accommodate six passengers and a crew of two. The Model 
390 will have a VMO/MMO of 320 knots/M.83, and 
has two turbofan engines mounted on the aft fuselage above and behind 
the wing.

Type Certification Basis

    Type certification basis of the Model 390 airplane is as follows: 
14 CFR part 23, effective February 1, 1965, through Amendment 23-52, 
effective July 25, 1996; 14 CFR part 36, effective December 1, 1969, 
through the amendment effective on the date of type certification; 14 
CFR part 34; exemptions, if any; and the special conditions adopted by 
this rulemaking action.

Discussion

    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).
    Raytheon plans to incorporate certain novel and unusual design 
features into the Model 390 airplane for which the airworthiness 
regulations do not contain adequate or appropriate safety standards. 
These features include turbofan engines, engine location, swept wings 
and stabilizer, and certain performance characteristics necessary for 
this type of airplane.

Performance

    The Raytheon Model 390 has a wing with 22.8 degrees of leading-edge 
sweepback and a T-tail configuration with trimmable horizontal 
stabilizer with 27.3 degrees of leading-edge sweepback. The Model 390 
will have a VMO/MMO of 320 knots/M.83, and it 
will have two 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 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 precise test 
measurements or specific detection systems. This phenomenon is not 
apparent to a pilot accustomed to operating a conventional airplane 
where

[[Page 58661]]

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, special conditions require 
performance standards for takeoff, takeoff speeds, accelerate-stop 
distance, takeoff path, takeoff distance, takeoff run, and takeoff 
flight path.
    Additionally, procedures for takeoff, accelerate-stop distance, and 
landing are proposed as those established for operation in service and 
must be executable by pilots of average skill and include reasonably 
expected time delays.

Climb

    To maintain a level of safety that is equivalent to the current 
business jet fleet for takeoff, takeoff speeds, takeoff path, takeoff 
distance, and takeoff run, it is appropriate to require specific climb 
gradients, airplane configurations, and consideration of atmospheric 
conditions that will be encountered. These special conditions include 
climb with one engine inoperative, balked landing climb, and general 
climb conditions.

Landing

    Landing distance determined for the same parameters 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.

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 existing business jet 
airplanes, it is appropriate to define applicable requirements for 
static longitudinal stability. Current standards in part 23 did not 
envision this type of airplane and the associated stability 
considerations. Special conditions will establish static longitudinal 
stability requirements that include a stick force versus speed 
specification and stability requirements applicable to high speed jet 
airplanes.
    Consistent 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.

Static Directional and Lateral Stability

    Consistent 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.

Stall Characteristics

    The stall characteristics requirements are relaxed from part 23 to 
be equivalent to that acceptable in current business jets. These 
special conditions reflect a higher expected pilot proficiency level, 
the remote chance that a stall will be encountered in normal operation, 
and the requirements are relaxed as compensation for meeting the higher 
performance requirements in these special conditions.

Vibration and Buffeting

    The Raytheon Model 390 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. The special condition 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.

High Speed Characteristics and Maximum Operating Limit Speed

    The Raytheon Model 390 will be operated at high altitude and high 
speeds. 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

[[Page 58662]]

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, the 
special conditions allow one to determine a maximum demonstrated flight 
speed and to relate the speeds VMO/MMO and 
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. These special conditions 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. Special conditions 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.

Takeoff Warning System

    Jet airplanes incorporating leading-edge sweep in the wing and 
horizontal tail and incorporating a trimmable horizontal tail have had 
accidents because of the criticality of the airplane's configuration at 
takeoff. Unlike simple, straight wing airplanes, an incorrect flap or 
horizontal tail trim setting can significantly alter the takeoff 
distance. Special conditions to require a takeoff warning system are 
proposed to maintain a level of safety appropriate for this class of 
aircraft.

Engine Fire Extinguishing System

    The Model 390 design includes engines mounted aft on the fuselage; 
therefore, early visual detection of engine fires is precluded. The 
applicable existing regulations do not require fire extinguishing 
systems for engines. Aft mounted engine installations were not 
envisaged in the development of part 23; therefore, special conditions 
for a fire extinguishing system with the applicable agents, containers, 
and materials for the engines of the Model 390 are appropriate.

Airspeed Indicating System

    To maintain a level of safety consistent with that existing in the 
current business jet fleet, 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 
pilot tube from malfunctions associated with icing conditions. Special 
conditions will establish airspeed indicating system calibration and 
pilot tube ice protection requirements applicable to transport category 
jet airplanes.

Static Pressure System

    Special conditions are 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 Raytheon Model 390 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 will 
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 that 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 will add 
maximum takeoff weights, maximum landing weights, and minimum takeoff 
distances as limitations in the AFM. Additionally, special conditions 
are included to add takeoff flight path and procedures necessary to 
achieve the performance in the limitations section as information in 
the AFM.

Effects of Contamination on Natural Laminar Flow Airfoils

    Airfoil configurations similar to the Raytheon Model 390 had 
measurable degradations of handling qualities and performance when 
laminar flow was lost due to airfoil contamination. Tripping of the 
boundary layer could be caused from flight in precipitation conditions 
or by the presence of contamination such as insects. If measurable 
effects are detected, it should be determined that the minimum flight 
characteristics standards continue to be met and that any degradations 
to performance information are identified. This may be accomplished by 
a combination of analysis and testing. Current standards in part 23 did 
not envision this type of airplane and the associated airfoil 
contamination considerations. Special considerations are issued since 
existing regulations do not require these adverse effects to be 
evaluated.

Conclusion

    In view of the design features discussed for the Raytheon Model 390 
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.

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, 44701, 44702, and 44704; 14 
CFR 21.16 and 21.17; and 14 CFR 11.28 and 11.29(b).

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

[[Page 58663]]

certification basis for the Raytheon Model 390 airplane:
SC23.45  Performance: General.
    Instead of the requirements of Sec. 23.45(g) and (h), the following 
apply:
    (g) The following, as applicable, must be determined on a smooth, 
dry, hard-surfaced runway--
    (1) Takeoff distance of special condition SC23.53;
    (2) Accelerate-stop distance of special condition SC23.55;
    (3) Takeoff distance and takeoff run of special condition SC23.59; 
and
    (4) Landing distance of special condition SC23.75.

    Note: The effect on these distances of operation on other types 
of surfaces (for example, grass, gravel), when dry, may be 
determined or derived and these surfaces listed in the Airplane 
Flight Manual.

    (h) Unless otherwise prescribed, the applicant must select the 
takeoff, enroute, approach, and landing configurations for the 
airplane.
    In addition to the requirements of Sec. 23.45 and the paragraphs 
above, the following apply:
    (i) The airplane configurations may vary with weight, altitude, and 
temperature to the extent that they are compatible with the operating 
procedures required by paragraph (d) of this special condition.
    (j) 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.
    (k) Procedures for the execution of balked landings and 
discontinued approaches associated with the conditions prescribed in 
special conditions SC23.77 and SC23.67(d) must be established.
    (l) The procedures established under paragraphs (d) and (e) 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.
SC23.49  Stalling speed.
    In Sec. 23.49(b), change the reference from ``Sec. 23.201'' to 
``Sec. 23.201 and special condition SC23.201.''
SC23.51  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) and special condition SC23.149(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, or
    (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 SC23.67(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 SC23.57(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 
SC23.57(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 SC23.59(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 
SC23.59.
    (f) VLOF is the calibrated airspeed at which the 
airplane first becomes airborne.
SC23.53  Takeoff performance.
    Instead of complying with Sec. 23.53, the following apply:
    (a) In special conditions SC23.51, SC23.55, SC23.57 and SC23.59, 
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; and
    (2) Effective runway gradients.

[[Page 58664]]

SC23.55  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.
SC23.57  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 SC23.67(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 SC23.45;
    (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; and
    (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.
SC23.59  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 SC23.57; 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 SC23.57.
    (b) If the takeoff distance includes a clear way, the takeoff run 
is the greater of the following:
    (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 
SC23.57; 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 SC23.57.
SC23.61  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 SC23.59.
    (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 SC23.57 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.
SC23.63  Climb: general.
    Instead of compliance with Sec. 23.63, the following applies:
    Compliance with the requirements of special conditions SC23.67 and 
SC23.77 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.
SC23.65  Climb: all engines operating.
    Delete requirement of Sec. 23.65.
SC23.66  Takeoff climb: One engine inoperative.
    Delete requirement of Sec. 23.66.
SC23.67  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 SC23.57 without

[[Page 58665]]

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 SC23.57, and
    (2) The weight equal to the weight existing when retraction of the 
landing gear begins, determined under special condition SC23.57.
    (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 
SC23.57, 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 SC23.57 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 
SC23.57.
    (c) Final takeoff. In the enroute configuration at the end of the 
takeoff path, determined in accordance with special condition SC23.57, 
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 SC23.57.
    (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.
SC23.73  Reference landing approach speed.
    In Sec. 23.73(b), change the reference from ``Sec. 23.149(c)'' to 
``special condition SC23.149.''
SC23.75  Landing distance.
    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 special condition SC23.73, 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; and
    (6) It must be shown that a safe transition to the balked landing 
conditions of special condition SC23.77 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.
SC23.77  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(b).
SC23.145  Longitudinal control.
    In Sec. 23.145(c), change the reference from ``Sec. 23.251'' to 
``special condition SC23.251.''
SC23.149  Minimum control speed.
    In Sec. 23.149(c), change the reference from ``Sec. 23.75'' to 
``special condition SC23.75.''
    Delete Sec. 23.149(d).
    In Sec. 23.149(f), delete ``At the option of the applicant, to 
comply with the requirements of Sec. 23.51(c)(1), VMCG may 
be determined.''
SC23.153  Control during landings.
    In Sec. 23.153(c), change the reference from ``Sec. 23.75'' to 
``special condition SC23.75.''
SC23.161  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.

[[Page 58666]]

    (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 SC23.75.
    (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.
SC23.171  [Stability] General.
    In Sec. 23.171, change reference from ``Secs. 23.173 through 
23.181'' to ``special conditions SC23.173, SC23.175, SC23.177, 
SC23.181, and Sec. 23.181.''
SC23.173  Static longitudinal stability.
    Instead of compliance with Sec. 23.173, the following apply:
    Under the conditions specified in special condition SC23.175, 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 SC23.175, 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 SC23.175, 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.
SC23.175  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 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 1.8 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.
SC23.177  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

[[Page 58667]]

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.
SC23.181  Dynamic stability.
    In Sec. 23.181(d), change the reference from Sec. 23.175 to 
SC23.175.
SC23.201 Wings level stall.
    In Sec. 23.201 (c), change the reference from ``Sec. 23.49'' to 
``Sec. 23.49 and special condition SC23.49.''
    Instead of compliance with Sec. 23.201 (d) and (e), the following 
apply:
    (d) The roll occurring between the stall and the completion of the 
recovery may not exceed approximately 20 degrees.
    (e) Compliance with the requirements of this section must be shown 
with:
    (1) Power--
    (i) Off; and
    (ii) The thrust 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).
    (2) Flaps and landing gear in any likely combination of positions.
    (3) Trim at 1.4 VS1 or at the minimum trim speed, 
whichever is higher.
    (4) Representative weights within the range for which certification 
is requested.
    (5) The most adverse center of gravity for recovery.
SC23.203  Turning flight and accelerated turning stalls.
    Instead of compliance with Sec. 23.203(c), the following apply:
    (c) Compliance with the requirements of this section must be shown 
with:
    (1) The thrust 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).
    (2) Flaps and landing gear in any likely combination of positions.
    (3) Trim at 1.4 VS1 or at the minimum trim speed, 
whichever is higher.
    (4) Representative weights within the range for which certification 
is requested.
    (5) The most adverse center of gravity for recovery.
SC23.207  Stall warning.
    Instead of compliance with Sec. 23.207(c), the following applies:
    (c) During the stall tests required by Sec. 23.201(b) and 
Sec. 23.203(a)(1), the stall warning must begin at a speed exceeding 
the stalling speed by seven percent or at any lesser margin if the 
stall warning has enough clarity, duration, distinctiveness, or similar 
properties.
SC23.251  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 SC23.1581.
    (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.
SC23.253  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.

[[Page 58668]]

    (b) Maximum speed for stability characteristics. VFC/
MFC. VFC/MFC is the maximum speed at 
which the requirements of special conditions SC23.173, SC23.175, 
SC23.177, SC23.181 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.
SC23.255  Out-of-trim characteristics.
    In the absence of specific requirements for out-of-trim 
characteristics, the Raytheon Model 390 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 +l 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 maneuvering 
load factors associated with probable inadvertent excursions beyond the 
boundaries of the buffet onset envelopes determined under special 
condition SC23.251(e), need not be exceeded. In addition, the entry 
speeds for flight test demonstrations at normal acceleration values 
less than 1g 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.
SC23.629  Flutter.
    Instead of the term/speed ``VD'' in Sec. 23.629(b), use 
``VDF/MDF.''
SC23.703  Takeoff warning system.
    In the absence of specific requirements for a takeoff warning 
system, the following apply:
    Unless it can be shown that a lift or longitudinal trim device that 
affects the takeoff performance of the aircraft would not give an 
unsafe takeoff configuration when selected out of an approved takeoff 
position, a takeoff warning system must be installed and meet the 
following requirements:
    (a) The system must provide to the pilots an aural warning that is 
automatically activated during the initial portion of the takeoff roll 
if the airplane is in a configuration that would not allow a safe 
takeoff. The warning must continue until--
    (1) The configuration is changed to allow safe takeoff, or
    (2) Action is taken by the pilot to abandon the takeoff roll.
    (b) The means used to activate the system must function properly 
for all authorized takeoff power settings and procedures and throughout 
the ranges of takeoff weights, altitudes, and temperatures for which 
certification is requested.
SC23.1195  Engine Fire Extinguishing System.
    (a) Fire extinguishing systems must be installed and compliance 
must be shown with the following:
    (1) Except for combustor, turbine, and tailpipe sections of 
turbine-engine installations that contain lines or components carrying 
flammable fluids for which a fire originating in these sections can be 
controllable, a fire extinguisher system must serve each engine 
compartment.
    (2) The fire extinguishing system, the quantity of the 
extinguishing agent, the rate of discharge, and the discharge 
distribution must be adequate to extinguish fires.
    (3) The fire extinguishing system for a nacelle must be able to 
simultaneously protect each compartment of the nacelle for which 
protection is provided.
    (b) Fire extinguishing agents must meet the following requirements:
    (1) Be capable of extinguishing flames emanating from any burning 
of fluids or other combustible materials in the area protected by the 
fire extinguishing system;
    (2) Have thermal stability over the temperature range likely to be 
experienced in the compartment in which they are stored; and
    (3) If any toxic extinguishing agent is used, provisions must be 
made to prevent harmful concentrations of fluid or fluid vapors from 
entering any personnel compartment even though a defect may exist in 
the extinguishing system. This must be shown by test except for built-
in carbon dioxide fuselage compartment fire extinguishing systems for 
which:
    (i) Five pounds or less of carbon dioxide will be discharged, under 
established fire control procedures, into any fuselage compartment; or
    (ii) Protective breathing equipment is available for each flight 
crew member on flight deck duty.

[[Page 58669]]

    (c) Fire extinguishing agent containers must meet the following 
requirements:
    (1) Each extinguishing agent container must have a pressure relief 
to prevent bursting of the container by excessive internal pressures.
    (2) The discharge end of each discharge line from a pressure relief 
connection must be located so the discharge of the fire extinguishing 
agent would not damage the airplane. The line must also be located or 
protected to prevent clogging caused by ice or other foreign matter.
    (3) A means must be provided for each fire extinguishing agent 
container to indicate that the container has discharged or that the 
charging pressure is below the established minimum necessary for proper 
functioning.
    (4) The temperature of each container must be maintained, under 
intended operating conditions, to prevent the pressure in the container 
from falling below that necessary to provide an adequate rate of 
discharge, or rising high enough to cause premature discharge.
    (5) If a pyrotechnic capsule is used to discharge the fire 
extinguishing agent, each container must be installed so that 
temperature conditions will not cause hazardous deterioration of the 
pyrotechnic capsule.
    (d) Fire extinguisher system materials must meet the following 
requirements:
    (1) No material in any fire extinguishing system may react 
chemically with any extinguishing agent so as to create a hazard; and
    (2) Each system component in an engine compartment must be 
fireproof.
SC23.1323  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 SC23.57, 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.
SC23.1325  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.
SC23.1501  [Operating Limitations and Information] General.
    Instead of the requirements of Sec. 23.1501(a), the following 
apply:
    (a) Each operating limitation specified in Secs. 23.1505 through 
23.1522, 23.1524 through 23.1527 and special conditions SC23.1505, 
SC23.1513, and SC23.1523.
SC23.1505  Airspeed limitations.
    In Sec. 23.1505(a)(2)(ii), change the reference from 
``Sec. 23.251'' to ``special condition SC23.251.''
    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 SC23.253.
SC23.1513  Minimum control speed.
    In Sec. 23.1513, change the reference from ``Sec. 23.149'' to 
``Sec. 23.149 and special condition SC23.149.''
SC23.1523  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.
SC23.1541  [Markings and Placards] General.
    Instead of Sec. 23.1541(a)(1), the following applies:
    (a)(1) The markings and placards specified in Secs. 23.1545 to 
23.1567 and special condition SC23.1545; and
SC23.1545  Airspeed indicator.
    In Sec. 23.1545(d), change the reference from ``Sec. 23.1505(c)'' 
to ``special condition SC23.1505.''
SC23.1581  [Airplane Flight Manual and Approved Manual Material.] 
General.
    In Sec. 23.1581 replace references to Sec. 23.1583, Sec. 23.1585, 
and Sec. 23.1587 with special conditions SC23.1583, SC23.1585, and 
SC23.1587, respectively.
SC23.1583  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 near the stall, should be confined to speeds 
below this value.

[[Page 58670]]

    (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 
Sec. 23.1549 through Sec. 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 SC23.67(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 SC23.67(d) and SC23.77 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 SC23.55 and 
SC23.59 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.
    (k) Maximum operating temperature. The maximum operating 
temperature established under Sec. 23.1521 must be furnished.
SC23.1585  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) Procedures for transition from landing approach to balk landing 
climb; and
    (7) 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 
SC23.251 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.
SC23.1587  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 
SC23.49.
    (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 SC23.45(d), (e), 
and (f) that are related to the limitations and

[[Page 58671]]

information required by special condition SC23.1583(h) 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.
SC23.A  Effects of contamination on natural laminar flow airfoils.
    In the absence of specific requirements for airfoil contamination, 
airplane airfoil designs that have airfoil pressure gradient 
characteristics and smooth aerodynamic surfaces that may be capable of 
supporting natural laminar flow must comply with the following:
    (a) It must be shown by tests, or analysis supported by tests, that 
the airplane complies with the requirements of Secs. 23.141 through 
23.207, 23.233, 23.251, 23.253 (and any changes made to these 
paragraphs by these special conditions) with any airfoil contamination 
that would normally be encountered in service and that would cause 
significant adverse effects on the handling qualities of the airplanes 
resulting from the loss of laminar flow.
    (b) Significant performance degradations identified as resulting 
from the loss of laminar flow must be provided as part of the 
information required by special conditions SC23.1585 and SC23.1587.

    Issued in Kansas City, Missouri on October 11, 1998.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-29301 Filed 10-30-98; 8:45 am]
BILLING CODE 4910-13-U