[Federal Register Volume 59, Number 34 (Friday, February 18, 1994)]
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From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-3620]


  Federal Register / Vol. 59, No. 34 / Friday, February 18, 1994 /
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[[Page Unknown]]

[Federal Register: February 18, 1994]


                                                    VOL. 59, NO. 34

                                          Friday, February 18, 1994
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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. 115CE, Special Condition 23-ACE-74]

 

Special Conditions; Cessna Model 526 Airplane

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

-----------------------------------------------------------------------

SUMMARY: These special conditions are being issued for the Cessna 
Aircraft Company Model 526 airplanes. These airplanes will have novel 
and unusual design features when compared to the state of technology 
envisaged in the applicable airworthiness standards. These design 
features include engine location, performance characteristics, and 
acrobatic maneuver capabilities, for which the applicable regulations 
do not contain adequate or appropriate airworthiness standards. These 
special conditions contain the additional airworthiness standards that 
the Administrator considers necessary to establish a level of safety 
equivalent to that provided by the current airworthiness standards.

EFFECTIVE DATE: March 21, 1994.

FOR FURTHER INFORMATION CONTACT:
Mike Downs, Aerospace Engineer, Standards Office (ACE-110), Small 
Airplane Directorate, Aircraft Certification Service, Federal Aviation 
Administration, 601 East 12th Street, Kansas City, Missouri 64106; 
telephone (816) 426-5688.

SUPPLEMENTARY INFORMATION:

Background

    On January 18, 1993, the Cessna Aircraft Co., P.O. Box 7704, 
Wichita, KS 67277 made application for acrobatic category type 
certification of the Model 526 airplane. This airplane is a two place 
(tandem seating), all metal, low wing, twin turbofan engine-powered 
monoplane with fully enclosed retractable landing gear. The Model 526 
has engines mounted on the fuselage sides aft and above the wing rear 
spar. The Model 526 is capable of acrobatic flight, including inverted 
maneuvers, and Mach .700 performance.

Type Certification Basis

    Type certification basis of the Cessna Model 526 airplane is as 
follows: Federal Aviation Regulations (14 CFR part 23), effective 
February 1, 1965, through amendment 23-42, effective February 4, 1991; 
14 CFR part 36, effective December 1, 1969, through amendment effective 
on the date of type certification; exemptions, if any; and the special 
conditions adopted by this rulemaking action.

Discussion

    Cessna plans to incorporate certain novel and unusual design 
features into the airplane for which the airworthiness regulations do 
not contain adequate or appropriate safety standards. These features 
include electronic systems, acrobatic flight capability, engine 
location, and certain performance characteristics necessary for this 
type of airplane that were not envisaged 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 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 Sec. 11.49 after public 
notice, as required by Secs. 11.28 and 11.29(b), effective October 14, 
1980, and become a part of the type certification basis, as provided by 
Sec. 21.17(a)(2).

Protection of Systems From High Intensity Radiated Fields (HIRF)

    Recent advances in technology have given rise to the application in 
aircraft designs of advanced electrical and electronic systems that 
perform functions required for continued safe flight and landing. Due 
to the use of sensitive solid state components in analog and digital 
electronics circuits, these advanced systems are readily responsive to 
the transient effects of induced electrical current and voltage caused 
by the HIRF incident on the external surface of aircraft. These induced 
transient currents and voltages can degrade electronic systems 
performance by damaging components or upsetting system functions.
    Furthermore, the electromagnetic environment has undergone a 
transformation that was not envisioned when the current requirements 
were developed. Higher energy levels are radiated from transmitters 
that are used for radar, radio, and television. Also, the population of 
transmitters has increased significantly.
    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 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 safety are based on 
surveys and analysis of existing radio frequency emitters. These 
special conditions require that the airplane be evaluated under the 
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 KHz.........................................        60        60
500-2000 KHz........................................        70        70
2-30 MHz............................................       200       200
30-70 MHz...........................................        30        30
70-100 MHz..........................................        30        30
100-200 MHz.........................................       150        33
200-400 MHz.........................................        70        70
400-700 MHz.........................................      4020       935
700-1000 MHz........................................      1700       170
1-2 GHz.............................................      5000       990
2-4 GHz.............................................      6680       840
4-6 GHz.............................................      6850       310
6-8 GHz.............................................      3600       670
8-12 GHz............................................      3500      1270
12-18 GHz...........................................      3500       360
18-40 GHz...........................................      2100       750
------------------------------------------------------------------------

    (2) The applicant may demonstrate by a laboratory test that the 
electrical and electronic systems that perform critical functions can 
withstand a peak of electromagnetic field strength of 100 volts per 
meter (v/m) in a frequency range of 10 KHz to 40 GHz. When using a 
laboratory test to show compliance with the HIRF requirements, no 
credit is given for signal attenuation due to installation.
    In view of the revised HIRF envelope, the requirement for the fixed 
value test has been changed to 100 v/m from the previously used value 
of 200 v/m. The applicant opting for the fixed value laboratory test, 
instead of the HIRF envelope, may be subject to post certification 
reassessment based on the finalized rule requirements. The applicant 
should be cautioned that choosing 100 v/m may make it difficult, under 
post certification reassessment requirements, to qualify the 
installations without upgrading the design. If the system should not 
meet the post certification reassessment requirements, additional 
protection provisions and/or testing may be required.
    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 
associated components, perform critical functions such as attitude, 
altitude, and airspeed indication. The HIRF requirements only apply to 
critical functions.
    Compliance with HIRF requirements may be demonstrated by tests, 
analysis, models, similarity with existing systems, or a combination 
thereof. 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.

Thrust Attenuation

    The Model 526 design includes a system that permits the attenuating 
of engine thrust. Attenuation is accomplished by movable panels, 
mounted on the engine pylons downstream of the exhaust cones, that can 
be deployed into the exhaust streams. The thrust attenuators are 
designed to be used in both ground and flight operations and differ 
from thrust reversers in that attenuators do not provide for either 
zero or reverse thrust levels. These special conditions provide 
requisite standards for thrust attenuating systems.

Flight

    Previous certification and operational experience with jet powered 
airplanes has not included an airplane of similar design or approval in 
the acrobatic category.
    Current standards in 14 CFR part 23 did not envisage this type of 
airplane and the associated performance and maneuvering capabilities. 
Based upon the knowledge and experience gained during certification and 
operation of previous part 23 jet airplanes and other acrobatic 
airplanes, special conditions similar to the requirements included in 
the draft Joint Airworthiness Regulations (JAR) 23, Issue 4 are 
proposed instead of the performance and flight characteristics 
requirements of subpart B of part 23.

Operating Limitations and Information

    Current standards in part 23 did not envisage this type of airplane 
and the associated performance and maneuvering capabilities.
    To maintain a level of safety consistent with other acrobatic 
category and jet powered airplanes, special conditions similar to the 
requirements included in the draft JAR 23, Issue 4 are proposed instead 
of the marking, placards, and flight manual requirements of subpart G 
of part 23.

Effects of Contamination on Natural Laminar Flow Airfoils

    Airfoil configurations similar to the Cessna Model 526 have been 
found to have measurable degradation 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 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 degradation to performance information are identified. This may be 
accomplished by a combination of analysis and testing. Current 
standards in part 23 did not envisage this type of airplane and the 
associated airfoil contamination. Special conditions are proposed since 
existing regulations do not require these adverse effects to be 
evaluated.

Discussion of Comments

    Notice of Proposed Special Conditions, Notice No. 23-ACE-74, was 
published in the Federal Register on October 12, 1993, and no comments 
were received. These special conditions are adopted as proposed with 
minor editorial corrections, except that Special Condition 23.49(a)(1) 
is reworded to correct an error in publication and Special Condition 
23.161(d)(2) is added due to its omission from the original 
publication.

Conclusion

    This action is not a rule of general applicability and affects only 
the model of airplane identified in these 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: Secs. 313(a), 601, and 603 of the Federal Aviation 
Act of 1958; as amended (49 U.S.C. 1354(a), 1421, and 1423); 49 
U.S.C. 106(g); 14 CFR 21.16 and 21.17; and 14 CFR 11.28 and 
11.29(b).

Adoption of Special Conditions

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the type certification basis for the Cessna Model 526 airplane:

    Note: To provide for clarity and continuity within the proposed 
special conditions, some sections of subparts B and G of part 23 are 
included without change in the following special conditions. These 
unchanged sections are marked with an asterisk (*) preceding the 
section number to permit them to be readily identified from the 
different/added requirements of the proposed special conditions.

1. Protection of Systems From High Intensity Radiated Fields (HIRF)

    Each system that performs critical functions must be designed 
and installed to ensure that the operation and operational 
capabilities of these critical functions are not adversely affected 
when the airplane is exposed to high intensity radiated 
electromagnetic fields external to the airplane.

2. Thrust Attenuating Systems

    Thrust attenuating systems must be designed and installed so 
that no unsafe condition will result during normal operation of the 
systems, or from any failure (or reasonably likely combination of 
failures) of the thrust attenuation systems under any anticipated 
condition of operation of the airplane, including ground operation. 
Failure of structural elements need not be considered if the 
probability of this kind of failure is extremely remote.

3. Flight

    Instead of compliance with the sections contained in subpart B 
of part 23, the following sections apply:

General

*SC23.21  Proof of Compliance

    (a) Each requirement of this subpart must be met at each 
appropriate combination of weight and center of gravity within the 
range of loading conditions for which certification is requested. 
This must be shown--
    (1) By tests upon an airplane of the type for which 
certification is requested, or by calculations based on, and equal 
in accuracy to, the results of testing; and
    (2) By systematic investigation of each probable combination of 
weight and center of gravity, if compliance cannot be reasonably 
inferred upon combinations investigated.
    (b) The following general tolerances are allowed during flight 
testing. However, greater tolerances may be allowed in particular 
tests--

------------------------------------------------------------------------
                Item                              Tolerance             
------------------------------------------------------------------------
Weight.............................  +5%, -10%                          
Critical items affected by weight..  +5%, -1%                           
CG.................................  plus-minuse>7% total travel        
------------------------------------------------------------------------

SC23.23  Load Distribution Limits

    (a) Ranges of weight and center of gravity within which the 
airplane may be safely operated must be established. If a weight and 
center of gravity combination is allowable only within certain 
lateral load distribution limits that could be inadvertently 
exceeded, these limits must be established for the corresponding 
weight and center of gravity combinations.
    (b) The load distribution must not exceed:
    (1) The selected limits;
    (2) The limits at which the structure is proven; or
    (3) The limits at which compliance with each applicable flight 
requirement of this subpart is shown.

SC23.25  Weight Limits

    (a) Maximum weight. The maximum weight is the highest weight at 
which compliance with each applicable requirement of part 23 (other 
than those complied with at the design landing weight) is shown. The 
maximum weight must be established so that it is--
    (1) Not more than the least of--
    (i) The highest weight selected by the applicant; or
    (ii) The design maximum weight, which is the highest weight at 
which compliance with each applicable structural loading condition 
of part 23 (other than those complied with at the design landing 
weight) is shown; or
    (iii) The highest weight at which compliance with each 
applicable flight requirement is shown; and
    (2) With each seat occupied, assuming a weight of 190 pounds, 
not less than the weight with--
    (i) Oil at full tank capacity, and at least enough fuel for 
maximum continuous thrust operation of at least 45 minutes; or
    (ii) The required minimum crew, and fuel and oil to full tank 
capacity.
    (b) Mimimum weight. The minimum weight (the lowest weight at 
which compliance with each applicable requirement of this part is 
shown) must be established so that it is not more than the sum of--
    (1) The empty weight determined under SC23.29;
    (2) The weight of the required minimum crew (assuming a weight 
of 170 pounds for each crew member); and
    (3) The weight of 5 percent of the total fuel capacity of that 
particular fuel tank arrangement under investigation.

SC23.29  Empty Weight and Corresponding Center of Gravity

    (a) The empty weight and corresponding center of gravity must be 
determined by weighing the airplane with--
    (1) Fixed ballast;
    (2) Unusable fuel determined under Sec. 23.959; and
    (3) Full operating fluids, including--
    (i) Oil;
    (ii) Hydraulic fluid; and
    (iii) Other fluids required for normal operation of airplane 
systems.
    (b) The condition of the airplane at the time of determining 
empty weight must be one that is well defined and can be easily 
repeated.

*SC23.31  Removable Ballast

    Removable ballast may be used in showing compliance with the 
flight requirements of this subpart, if--
    (a) The place for carrying ballast is properly designed and 
installed, and is marked under SC23.1557; and
    (b) Instructions are included in the Airplane Flight Manual, 
approved manual material, or markings and placards, for the proper 
placement of the removable ballast under each loading condition for 
which removable ballast is necessary.

SC23.45  Performance--General

    (a) The performance requirements of this subpart must be met 
for: Still air; and Ambient atmospheric conditions.
    (b) Unless otherwise prescribed, performance data must be 
provided over not less than the following ranges of conditions:
    (1) Airport altitude from seal level to 10,000 feet; and
    (2) Temperature from standard to 30  deg.C above standard, or 
the maximum ambient atmospheric temperature at which compliance with 
the cooling provisions of Secs. 23.1041 to 23.1045 is shown, if 
lower.
    (c) Performance data must be determined with the means for 
controlling the engine cooling air supply in the position used in 
the cooling tests required by Secs. 23.1041 to 23.1045.
    (d) The available propulsive thrust must correspond to engine 
thrust not exceeding the approved thrust, less:
    (1) Installation losses; and
    (2) The equivalent thrust absorbed by the accessories and 
services appropriate to the particular ambient atmospheric 
conditions and the particular flight condition.
    (e) The performance as affected by engine thrust must be based 
on a relative humidity of:
    (1) 80 percent at and below standard temperature; and
    (2) 34 percent at and above standard temperature plus 50  deg.F.
    Between the two temperatures the relative humidity must vary 
linearly.
    (f) Unless otherwise prescribed in determining the takeoff and 
landing distances, changes in the airplane's configuration, speed 
and thrust must be made in accordance with procedures established by 
the applicant for operation in service. The procedures must be able 
to be executed consistently by pilots of average skill in 
atmospheric conditions reasonably expected to be encountered in 
service.
    (g) The takeoff and landing distances must be determined on a 
smooth dry hard-surfaced runway. The effect on these distances of 
operation on other types of surface (for example, grass, gravel) 
when dry, may be derived and these surfaces listed under 
SC23.1583(o).

SC23.49  Stalling Speed

    (a) VSO and VS1 are the stalling speeds or the minimum 
steady fight speed, in knots (CAS), at which the airplane is 
controllable with--
    (1) The propulsive thrust not greater than zero 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 airplane in the condition existing in the test in which 
VSO and VS1 are being made;
    (3) Center of gravity in the position which results in the 
highest value of VSO and VS1; and
    (4) Weight used when VSO and VS1 are being used as a 
factor to determine compliance with a required performance standard.
    (b) VSO and VS1 must be determined by flight tests 
using the procedure and meeting the flight characteristics specified 
in SC23.201.

SC23.51  Takeoff Speeds

    (a) The rotation speed VR, is the speed at which the pilot 
makes a control input with the intention of lifting the airplane out 
of contact with the runway. VR must not be less than the 
greater of 1.05 VMC and 1.10 VS1.
    (b) The speed at 50 feet must not be less than the highest of:
    (1) A speed that is shown to be safe for continued flight (or 
emergency landing, if applicable) under all reasonably expected 
conditions, including turbulence and complete failure of the 
critical engine; or
    (2) 1.10 VMC; or
    (3) 1.20 VS1.

SC23.53  Takeoff Distance

    (a) The takeoff distance must be determined in accordance with 
subparagraph (b), using speeds determined in accordance with 
SC23.51(a) and (b).
    (b) The distance required to takeoff and climb to a height of 50 
feet above the takeoff surface must be determined for each weight, 
altitude and temperature within the operational limits established 
for takeoff with--
    (1) Takeoff thrust on each engine;
    (2) Wing flaps in the takeoff position(s); and
    (3) Landing gear extended.

SC23.63  Climb: General

    (a) Compliance with the requirements of SC23.65, SC23.66, 
SC23.67, SC23.69 and SC23.77 must be shown--
    (1) Out of ground effect; and
    (2) At speeds that are not less than those at which compliance 
with the powerplant cooling requirements of Secs. 23.1041 to 23.1045 
have been demonstrated.
    (b) Compliance must be shown, at weights, as a function of 
airport altitude and ambient temperature, within the operational 
limits established for takeoff and landing respectively, with--
    (1) SC23.65 and SC23.67(a) and (b) for takeoff; and
    (2) SC23.67(b) and SC23.77 for landing.

SC23.65  Climb: All Engines Operating

    The airplane must have a steady gradient of climb after takeoff 
of at least 4 percent with--
    (a) Takeoff thrust on each engine;
    (b) Landing gear extended except that, if the landing gear can 
be retracted in not more than 7 seconds, it may be assumed to be 
retracted;
    (c) Wing flaps in the takeoff position(s); and
    (d) A climb speed not less than the greater of 1.1 VMCA and 
1.2 VS1.

SC23.66  Takeoff Climb: One-Engine Inoperative

    The steady gradient of climb or descent must be determined at 
each weight, altitude and ambient temperature within the operational 
limits established by the applicant with--
    (a) Critical engine inoperative;
    (b) Remaining engine at takeoff thrust;
    (c) Landing gear extended except that, if the landing gear can 
be retracted in not more than 7 seconds, it may be assumed to be 
retracted;
    (d) Wing flaps in the takeoff position(s);
    (e) Wings level; and
    (f) Climb speed equal to that achieved at 50 feet in the 
demonstration of SC23.53.

SC23.67  Climb: One-Engine Inoperative

    (a) The steady gradient of climb at an altitude of 400 feet 
above the takeoff surface must be measurably positive with the--
    (1) Critical engine inoperative;
    (2) Remaining engine at takeoff thrust;
    (3) Landing gear retracted;
    (4) Wing flaps in the takeoff position(s); and
    (5) Climb speed equal to that achieved at 50 feet in the 
demonstration of SC23.53.
    (b) The steady gradient of climb may not be less than 0.75 
percent at an altitude of 1500 feet above the takeoff or landing 
surface, as appropriate, with the--
    (1) Critical engine inoperative;
    (2) Remaining engine at not more than maximum continuous thrust;
    (3) Landing gear retracted;
    (4) Wing flaps retracted; and
    (5) Climb speed not less than 1.2 VS1.

SC23.69  En-Route Climb/Descent

    (a) All engines operating.
    The steady gradient and rate of climb must be determined at each 
weight, altitude and ambient temperature within the operational 
limits established by the applicant with--
    (1) Not more than maximum continuous thrust on each engine;
    (2) Landing gear retracted;
    (3) Wing flaps retracted; and
    (4) Climb speed not less than 1.3 VS1.
    (b) One-engine inoperative.
    The steady gradient and rate of climb/descent must be determined 
at each weight, altitude and ambient temperature within the 
operational limits established by the applicant with--
    (1) Critical engine inoperative;
    (2) Remaining engine at not more than maximum continuous thrust;
    (3) Landing gear retracted;
    (4) Wing flaps retracted; and
    (5) Climb speed not less than 1.2 VS1.

SC23.73  Reference Landing Approach Speed

    The reference landing approach speed, VREF, must not be 
less than the greater of VMC, determined under SC23.149(c) with 
the wing flaps in the landing position, and 1.3 VS0.

SC23.75  Landing Distance

    The horizontal distance necessary to land and come to a complete 
stop from a point 50 feet above the landing surface must be 
determined, for standard temperatures at each weight and altitude 
within the operational limits established for landing, as follows:
    (a) A steady approach at not less than VREF must be 
maintained down to the 50-foot height and--
    (1) The steady approach must be at a gradient of descent not 
greater than 5.2 percent (3 degrees) down to the 50-foot height; and
    (2) In addition, an applicant may demonstrate by tests that a 
maximum steady approach gradient, steeper than 5.2 percent, down to 
the 50-foot height is safe. The gradient must be established as an 
operating limitation and the information necessary to display the 
gradient must be available to the pilot by an appropriate 
instrument.
    (b) A constant configuration must be maintained throughout the 
maneuver.
    (c) The landing must be made without excessive vertical 
acceleration or tendency to bounce, nose-over, ground loop, or 
porpoise.
    (d) It must be shown that a safe transition to the balked 
landing conditions of SC23.77 can be made from the conditions that 
exist at the 50-foot height, at maximum landing weight or the 
maximum landing weight for altitude and temperature of 
SC23.63(b)(2), as appropriate.
    (e) The brakes must not be used so as to cause excessive wear of 
brakes or tires.
    (f) Retardation means other than wheel brakes may be used if 
that means--
    (1) Is safe and reliable;
    (2) Is used so that consistent results can be expected in 
service; and
    (3) If any device is used that depends on the operation of any 
engine, and the landing distance would be increased when a landing 
is made with that engine inoperative; the landing distance must be 
determined with that engine inoperative, unless the use of other 
compensating means will result in a landing distance not more than 
that with each engine operating.

SC23.77  Balked Landing

    The steady gradient of climb must not be less than 2.5 percent 
with--
    (a) Not more than the thrust that is available 8 seconds after 
initiation of movement of the thrust controls from the minimum 
flight idle position;
    (b) The landing gear extended;
    (c) The wing flaps in the landing position; and
    (d) A climb speed equal to VREF, as defined in SC23.73.

Flight Characteristics

SC23.141  General

    The airplane must meet the requirements of SC23.143 through 
SC23.253 at all practical loading conditions and operating altitudes 
for which certification has been requested, not exceeding the 
maximum operating altitude established under SC23.1527 and without 
requiring exceptional piloting skill, alertness, or strength.

Controllability and Maneuverability

SC23.143  General

    (a) The airplane must be safely controllable and maneuverable 
during all flight phases including--
    (1) Takeoff;
    (2) Climb;
    (3) Level flight;
    (4) Descent;
    (5) Go-around; and
    (6) Landing (power on and power off) with the wing flaps 
extended and retracted.
    (b) It must be possible to make a smooth transition from one 
flight condition to another (including turns and slips) without 
danger of exceeding the limit load factor, under any probable 
operating condition, including those conditions normally encountered 
in the sudden failure of any engine.
    (c) If marginal conditions exist with regard to required pilot 
strength, the control forces required must be determined by 
quantitative tests. In no case may the control forces under the 
conditions specified in paragraphs (a) and (b) exceed those 
prescribed in the following table:

------------------------------------------------------------------------
 Values in pounds force applied to the relevant                         
                     control                       Pitch   Roll     Yaw 
------------------------------------------------------------------------
For temporary application:                                              
    Stick.......................................      60      30  ......
    Rudder pedal................................  ......  ......     150
For prolonged application.......................      10       5      20
------------------------------------------------------------------------

SC23.145  Longitudinal Control

    (a) With the airplane as nearly as possible in trim at 1.3 
VS1, it must be possible, at speeds below the trim speed, to 
pitch the nose downward so that the rate of increase in airspeed 
allows prompt acceleration to the trim speed with--
    (1) Maximum continuous thrust on each engine;
    (2) Power off; and
    (3) Wing flaps and landing gear--
    (i) Retracted; and
    (ii) Extended.
    (b) It must be possible to carry out the following maneuvers 
without requiring the application of control forces exceeding those 
specified in SC23.143(c). The trimming controls must not be adjusted 
during the maneuvers:
    (1) With landing gear extended and flaps retracted and the 
airplane as nearly as possible in trim at 1.4 VS1, extend the 
flaps as rapidly as possible and allow the airspeed to transition 
from 1.4 VS1 to 1.4 VSO, with--
    (i) Power off; and
    (ii) Thrust necessary to maintain level flight in the initial 
condition.
    (2) With landing gear and flaps extended, power off and the 
airplane as nearly as possible in trim at 1.3 VSO, quickly 
apply takeoff thrust and retract the flaps as rapidly as possible to 
the recommended balked landing setting and allow the airspeed to 
transition from 1.3 VSO to 1.3 VS1. Retract the gear when 
a positive rate of climb is established.
    (3) With landing gear and flaps extended, thrust for and in 
level flight at 1.1 VSO and the airplane as nearly as possible 
in trim, it must be possible to maintain approximately level flight 
while retracting the flaps as rapidly as possible with simultaneous 
application of not more than maximum continuous thrust. If gated 
flap positions are provided, the flap retraction may be demonstrated 
in stages with thrust and trim reset for level flight at 1.1 
VS1 in the initial configuration for each stage--
    (i) From the fully extended position to the most extended gated 
position;
    (ii) Between intermediate gated positions, if applicable; and
    (iii) From the least extended gated position to the fully 
retracted position.
    (4) With power off, flaps and landing gear retracted and the 
airplane as nearly as possible in trim at 1.4 VS1, apply 
takeoff thrust rapidly while maintaining the same airspeed.
    (5) With power off, landing gear and flaps extended and the 
airplane as nearly as possible in trim at VREF, obtain and 
maintain airspeeds between 1.1 VSO and either 1.7 VSO or 
VFE, whichever is lower.
    (6) With maximum takeoff thrust, landing gear retracted, flaps 
in the takeoff position(s) and the airplane as nearly as possible in 
trim at VFE appropriate to the takeoff flap position, retract 
the flaps as rapidly as possible while maintaining speed constant.
    (c) At speeds above VMO/MMO and up to the maximum 
speed shown under SC23.251, a maneuvering capability of 1.5g must be 
demonstrated to provide a margin to recover from upset or 
inadvertent speed increase.
    (d) It must be possible, with a pilot control force of not more 
than 10 pounds, to maintain a speed of not more than VREF 
during a power-off glide with landing gear and wing flaps extended.
    (e) By using normal flight and thrust controls, except as 
otherwise noted in paragraphs (e)(1) and (e)(2) of this section, it 
must be possible to establish a zero rate of descent at an attitude 
suitable for a controlled landing without exceeding the operational 
and structural limitations of the airplane, as follows:
    (1) Without the use of the primary longitudinal control system;
    (2) Without the use of the primary directional control; and
    (3) If a single failure of any one connecting or transmitting 
link would affect both the longitudinal and directional primary 
control system, without the primary longitudinal and directional 
control system.

SC23.147  Directional and Lateral Control

    (a) It must be possible, while holding the wings level within 5 
degrees, to make sudden changes in heading safely in both 
directions. This must be shown at 1.4 VS1 with heading changes 
up to 15 degrees (except that the heading change at which the rudder 
force corresponds to the limits specified in SC23.143 need not be 
exceeded), with the--
    (1) Critical engine inoperative;
    (2) Remaining engine at maximum continuous thrust;
    (3) Landing gear--
    (i) Retracted; and
    (ii) Extended.
    (4) Flaps retracted.
    (b) It must be possible to regain full control of the airplane 
without exceeding a bank angle of 45 degrees, reaching a dangerous 
attitude or encountering dangerous characteristics, in the event of 
a sudden and complete failure of the critical engine, making 
allowance for a delay of 2 seconds in the initiation of recovery 
action appropriate to the situation, with the airplane initially in 
trim, in the following conditions--
    (1) Maximum continuous thrust on each engine;
    (2) Wing flaps retracted;
    (3) Landing gear retracted; and
    (4) Speed equal to that at which compliance with SC23.69(a) has 
been shown.
    (c) It must be shown that the airplane is safely controllable 
without the use of the primary lateral control system in any 
configuration and at any speed or altitude within the approved 
operating envelope and that the airplane's flight characteristics 
are not impaired below a level needed to permit continued safe 
flight and the ability to maintain attitudes suitable for a 
controlled landing without exceeding the operational and structural 
limitations of the airplane. If a single failure of any one 
connecting or transmitting link in the lateral control system would 
also cause the loss of additional control system(s), the above 
requirement is equally applicable with those additional systems also 
assumed to be inoperative.

SC23.149  Minimum Control Speed

    (a) VMC is the calibrated airspeed at which, when the 
critical engine is suddenly made inoperative, it is possible to 
recover control of the airplane, with that engine still inoperative, 
and thereafter maintain straight flight at the same speed with an 
angle of bank not more than 5 degrees. The method used to simulate 
critical engine failure must represent the most critical mode of 
powerplant failure with respect to controllability expected in 
service.
    (b) VMC for takeoff must not exceed 1.2 VS1, (where 
VS1 is determined at the maximum takeoff weight) and must be 
determined with the most unfavorable weight and center of gravity 
position and with the airplane airborne and the ground effect 
negligible, for the takeoff configuration(s) with--
    (1) Maximum available takeoff thrust initially on each engine;
    (2) The airplane trimmed for takeoff;
    (3) Flaps in the takeoff position(s); and
    (4) Landing gear retracted.
    (c) The VMC requirements of (a) must also be met for the 
landing configuration with--
    (1) Maximum available takeoff thrust initially on each engine;
    (2) The airplane trimmed for an approach with all engines 
operating at VREF at an approach gradient equal to the steepest 
used in the landing distance demonstration of SC23.75;
    (3) Flaps in the landing position; and
    (4) Landing gear extended.
    (d) At VMC the rudder pedal force required to maintain 
control must not exceed 150 pounds and it must not be necessary to 
reduce thrust of the operative engine. During recovery, the airplane 
must not assume any dangerous attitude and it must be possible to 
prevent a heading change of more than 20 degrees.
    (e) A minimum speed to intentionally render the critical engine 
inoperative must be established and designated as the safe, 
intentional, one-engine-inoperative speed, VSSE.

SC23.151  Acrobatic Maneuvers

    (a) The airplane must be able to perform safely acrobatic 
maneuvers for which certification is requested. Safe entry speeds 
for these maneuvers must be determined.
    (b) It must be possible to safely recover control of the 
airplane following inadvertent upsets encountered during the 
acrobatic maneuvers for which certification is requested.
    (c) The airplane must meet the emergency egress requirements of 
Sec. 23.807(b)(5).
    (d) The airplane must meet the following spin requirements:
    (1) One-turn spins. The airplane must recover from a one-turn 
spin or a three second spin, whichever takes longer, in not more 
than one additional turn, after initiation of the first control 
action for recovery. In addition--
    (i) For both the flaps retracted and flaps extended conditions, 
the applicable airspeed limit and positive limit maneuvering load 
factor must not be exceeded;
    (ii) No control forces or characteristics encountered during the 
spin or recovery may adversely affect prompt recovery;
    (iii) It must be impossible to obtain unrecoverable spins with 
any use of the flight or engine power controls either at the entry 
into or during the spin; and
    (iv) For the flaps extended condition, the flaps may be 
retracted during the recovery, but not before rotation has ceased.
    (2) Six-turn (or greater) spins: The following requirements must 
be met in each configuration for which approval for spinning is 
requested:
    (i) The airplane must readily recover from any point in a spin 
up to and including six turns, or any greater number of turns for 
which certification is requested, in not more than one and one half 
additional turns after initiation of the first control action for 
recovery. However, beyond three turns, the spin may be discontinued 
if spiral characteristics appear;
    (ii) The applicable airspeed limits and limit maneuvering load 
factors must not be exceeded. For flaps extended configurations for 
which approval is requested, the flaps must not be retracted during 
the recovery;
    (iii) It must be impossible to obtain unrecoverable spins with 
any use of the flight or engine power controls either at the entry 
into or during the spin; and
    (iv) There must be no characteristics during the spin (such as 
excessive rates of rotation or extreme oscillatory motion) that 
might prevent a successful recovery due to disorientation or 
incapacitation of the pilot.

SC23.153  Control During Landings

    It must be possible, while in the landing configuration, to 
safely complete a landing without exceeding the control force limits 
specified in SC23.143(c) following an approach to land--
    (a) At a speed of VREF--5 kts;
    (b) With the airplane in trim, or as nearly as possible in trim 
and without the trimming control being moved throughout the 
maneuver;
    (c) At an approach gradient equal to the steepest used in the 
landing distance demonstration of SC23.75; and
    (d) With only those thrust changes, if any, which would be made 
when landing normally from an approach at VREF.

SC23.155  Elevator Control Force in Maneuvers

    (a) The elevator control force needed to achieve the positive 
limit maneuvering load factor may not be less than W/140 (where W is 
the maximum weight) or 15 pounds, whichever is greater, except that 
it need not be greater than 35 pounds.
    (b) The requirement of paragraph (a) of this section must be met 
at maximum continuous thrust with the wing flaps and landing gear 
retracted--
    (1) In a turn, with the trim setting used for wings level flight 
at VO; and
    In a turn, with the trim setting used for the maximum wings 
level flight speed, except that the speed need not exceed VMO/
MMO.
    (c) There must be no excessive decrease in the gradient of the 
curve of stick force versus maneuvering load factor with increasing 
load factor.

SC23.157  Rate of Roll

    (a) Takeoff. It must be possible, using a favorable combination 
of controls, to roll the airplane from a steady 30 degree banked 
turn through an angle of 60 degrees, so as to reverse the direction 
of the turn within W+5001300 seconds, where W is the weight 
in pounds.
    (b) The requirement of paragraph (a) of this section must be met 
when rolling the airplane in each direction with--
    (1) Flaps in the takeoff position(s);
    (2) Landing gear retracted;
    (3) With the critical engine inoperative and the remaining 
engine at maximum takeoff thrust; and
    (4) The airplane trimmed at a speed equal to the greater of 1.2 
VS1 or 1.1 VMC or as nearly as possible in trim for 
straight flight.
    (c) Approach. It must be possible using a favorable combination 
of controls, to roll the airplane from a steady 30 degree banked 
turn through an angle of 60 degrees, so as to reverse the direction 
of the turn within W+28002200 seconds, where W is the weight 
in pounds.
    (d) The requirement of paragraph (c) of this section must be met 
when rolling the airplane in each direction in the following 
conditions:
    (1) Flaps in the landing position(s);
    (2) Landing gear extended;
    (3) All engines operating at the thrust for a 3 degree approach; 
and
    (4) The airplane trimmed at VREF.

Trim

SC23.161  Trim

    (a) General. Each airplane must meet the trim requirements of 
this section 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. In addition, it must 
be possible, in other conditions of loading, configuration, speed 
and thrust to ensure that the pilot will not be unduly fatigued or 
distracted by the need to apply residual control forces exceeding 
those for prolonged application specified in SC23.143(c) This 
applies in normal operation of the airplane and, if applicable, to 
those conditions associated with the failure of one engine for which 
performance characteristics are established.
    (b) Lateral and directional trim. The airplane must maintain 
lateral and directional trim in level flight at 0.9 VH, VC 
or VMO/MMO, whichever is lowest, with the landing gear and 
wing flaps retracted.
    (c) Longitudinal trim. The airplane must maintain longitudinal 
trim under each of the following conditions:
    (1) A climb with:
    (i) Takeoff thrust, landing gear retracted, wing flaps in the 
takeoff position(s), at the speeds used in determining the climb 
performance required by SC23.65; and
    (ii) Maximum continuous thrust at the speeds and in the 
configuration used in determining the climb performance required by 
SC23.69(a).
    (2) Level flight at all speeds from the lesser of VH and 
VMO/MMO (as appropriate), to 1.4 VS1, with the 
landing gear and flaps retracted.
    (3) A descent at VMO/MMO with power off and with the 
landing gear and flaps retracted.
    (4) Approach with landing gear extended and with--
    (i) A 3 degree angle of descent, with flaps retracted and at a 
speed of 1.4 VS1;
    (ii) A 3 degree angle of descent, flaps in the landing 
position(s) at VREF; and
    (iii) An approach gradient equal to the steepest used in the 
landing distance demonstrations of SC23.75, flaps in the landing 
position(s) at VREF.
    (d) The airplane must maintain longitudinal and directional trim 
and the lateral control force must not exceed 5 pounds, at the speed 
used in complying with SC23.67(b) with--
    (1) The critical engine inoperative;
    (2) The remaining engine at maximum continuous thrust;
    (3) The landing gear retracted;
    (4) The wing flaps retracted; and
    (5) An angle of bank of not more than 5 degrees.

Stability

*SC23.171  General

    The airplane must be longitudinally, directionally and laterally 
stable under SC23.173 through SC23.181. In addition, the airplane 
must show suitable stability and control ``feel'' (static stability) 
in any condition normally encountered in service, if flight tests 
show it is necessary for safe operation.

SC23.173  Static Longitudinal Stability

    Under the conditions specified in SC23.175 and with the airplane 
trimmed as indicated, the characteristics of the elevator control 
forces and the friction within the control system must be as 
follows:
    (a) A pull must be required to obtain and maintain speeds below 
the specified trim speed and a push required to obtain and maintain 
speeds above the specified trim speed. This must be shown at any 
speed that can be obtained, except that speeds requiring a control 
force in excess of 40 pounds or speeds above the maximum allowable 
speed or below the minimum speed for steady unstalled flight, need 
not be considered.
    (b) The airspeed must return to within plus or minus 10 percent 
of the original trim speed when the control force is slowly released 
at any speed within the speed range specified in paragraph (a) of 
this section.
    (c) The stick force must vary with speed so that any substantial 
speed change results in a stick force clearly perceptible to the 
pilot.

SC23.175  Demonstration of Static Longitudinal Stability

    Static longitudinal stability must be shown as follows:
    (a) Climb. The stick force curve must have a stable slope, at 
speeds between 85 percent and 115 percent of the trim speed, with--
    (1) Flaps retracted;
    (2) Landing gear retracted;
    (3) Maximum continuous thrust; and
    (4) The airplane trimmed at the speed used in determining the 
climb performance required by SC23.69(a).
    (b) Cruise. With flaps and landing gear retracted and the 
airplane in trim with thrust for level flight at representative 
cruising speeds at high and low altitudes, including speeds up to 
VMO/MMO, as appropriate, except that the speed need not 
exceed VH.
    (1) The stick force curve must have a stable slope at all speeds 
within a range that is the greater of 15 percent of the trim speed 
plus the resulting free return speed range, or 40 knots plus the 
resulting free return speed range, above and below the trim speed, 
except that the slope need not be stable--
    (i) At speeds less than 1.3 VS1; and
    (ii) At speeds greater than VFC/MFC.
    (c) Landing. The stick force curve must have a stable slope at 
speeds between 1.1 VS1 and 1.8 VS1 with--
    (1) Flaps in the landing position(s);
    (2) Landing gear extended; and
    (3) The airplane trimmed at--
    (i) VREF, or the minimum trim speed if higher, with power 
off; and
    (ii) VREF with enough thrust to maintain a 3 degree angle 
of descent.

SC23.177  Static Directional and Lateral Stability

    (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 appropriate to the takeoff, 
climb, cruise, approach and landing configurations. This must be 
shown with symmetrical thrust up to maximum continuous thrust and at 
speeds from 12 VS1 up to maximum allowable speed for the 
condition being investigated. The angle of sideslip for these tests 
must be appropriate to the type of airplane. At larger angles of 
sideslip up to that at which full rudder is used or a control force 
limit in SC23.143 is reached, whichever occurs first, and at speeds 
from 1.2 VS1 to VO the rudder pedal force must not 
reverse.
    (b) The static lateral stability, as shown by the tendency to 
raise the low wing in a sideslip, must be positive for all landing 
gear and flap positions. This must be shown with symmetrical power 
up to 75 percent maximum continuous thrust at speeds above 1.2 
VS1 in the takeoff configuration(s) and at speeds above 1.3 
VS1 in other configurations, up to the maximum allowable speed 
for the configuration being investigated, in the takeoff, climb, 
cruise, and approach configurations. For the landing configuration, 
the power must be up to that necessary to maintain a 3 degree angle 
of descent in coordinated flight. The static lateral stability must 
not be negative at 1.2 VS1 in the takeoff configuration(s), or 
at 1.3 VS1 in other configurations. The angle of sideslip for 
these tests must be appropriate to the type of airplane but in no 
case may the constant heading sideslip angle be less than that 
obtainable with a 10 degree bank, or if less, the maximum bank angle 
obtainable with full rudder deflection or 150 pound rudder force.
    (c) Paragraph (b) of this section does not apply to acrobatic 
category airplanes certificated for unlimited inverted flight.
    (d) In straight, steady sideslips at 1.2 VS1 for any 
landing gear and flap positions and for any symmetrical thrust 
conditions up to 50 percent of maximum continuous thrust, the 
aileron and rudder control movements and forces must increase 
steadily (but not necessarily in constant proportion) as the angle 
of sideslip is increased up to the maximum appropriate to the type 
of airplane. At larger sideslip angles up to the angle at which full 
rudder or aileron control is used or a control force limit contained 
in SC23.143 is obtained, the aileron and rudder control movements 
and forces must not reverse as the angle of sideslip is increased. 
Rapid entry into, or recovery from, a maximum sideslip considered 
appropriate for the airplane must not result in uncontrollable 
flight characteristics.

SC23.181 Dynamic Stability

    (a) Any short period oscillation not including combined lateral-
directional oscillations occurring between the stalling speed and 
the maximum allowable speed appropriate to the configuration of the 
airplane must be heavily damped with the primary controls--
    (1) Free; and
    (2) In a fixed position.
    (b) Any combined lateral-directional oscillations (``Dutch 
roll'') occurring between the stalling speed and the maximum 
allowable speed appropriate to the configuration of the airplane 
must be damped to \1/10\ amplitude in 7 cycles with the primary 
controls--
    (1) Free; and
    (2) In a fixed position.
    (c) If it is determined that the function of a stability 
augmentation system, reference Sec. 23.672, is needed to meet the 
flight characteristic requirements of this part, the primary control 
requirements of paragraphs (a)(2) and (b)(2) of this section are not 
applicable to the tests needed to verify the acceptability of that 
system.
    (d) During the conditions as specified in SC23.175, when the 
longitudinal control force required to maintain speeds differing 
from the trim speed by at least plus and minus 15 percent is 
suddenly released, the response of the airplane must not exhibit any 
dangerous characteristics nor be excessive in relation to the 
magnitude of the control force released. Any long-period oscillation 
of flight path, phugoid oscillation, that results must not be so 
unstable as to increase the pilot's workload or otherwise endanger 
the airplane.

Stalls

SC23.201  Wings Level Stall

    (a) It must be possible to produce and to correct roll by 
unreversed use of the rolling control and to produce and to correct 
yaw by unreversed use of the directional control, up to the time the 
airplane stalls.
    (b) The wings level stall characteristics must be demonstrated 
in flight as follows. Starting from a speed at least 10 knots above 
the stall speed, the elevator control must be pulled back so that 
the rate of speed reduction will not exceed one knot per second 
until a stall is produced, as shown by either:
    (1) an uncontrollable downward pitching motion of the airplane; 
or
    (2) the control reaching the stop.
    (c) Normal use of elevator control for recovery is allowed after 
the downward pitching motion of paragraph (b)(1) of this special 
condition has unmistakably been produced, or after the control has 
been held against the stop for not less than the longer of two 
seconds or the time employed in the minimum steady flight speed 
determination of SC23.49.
    (d) During the entry into and the recovery from the maneuver, it 
must be possible to prevent more than 15 degrees of roll or yaw by 
the normal use of controls.
    (e) Compliance with the requirements of this section must be 
shown under the following conditions:
    (1) Wing flaps: Retracted, fully extended and each intermediate 
normal operating position;
    (2) Landing gear: Retracted and extended;
    (3) Power: Power off and 75 percent maximum continuous thrust. 
If the thrust-to-weight ratio at 75 percent maximum continuous 
thrust results in extremely nose-high attitudes, the test may be 
accomplished with the power required for level flight in the landing 
configuration at maximum landing weight and a speed of 1.4 VSO, 
but the power may not be less than 50 percent of maximum continuous 
thrust.
    (4) Trim: The airplane trimmed at a speed as near 1.5 VS1 
as practicable.

SC23.203  Turning Flight and Accelerated Turning Stalls

    Turning flight and accelerated turning stalls must be 
demonstrated in tests as follows:
    (a) Establish and maintain a coordinated turn in a 30 degree 
bank. Reduce speed by steadily and progressively tightening the turn 
with the elevator until the airplane is stalled, as defined in 
SC23.201(b). The rate of speed reduction must be constant, and--
    (1) For a turning flight stall, may not exceed one knot per 
second; and
    (2) For an accelerated turning stall, be 3 to 5 knots per second 
with steadily increasing normal acceleration.
    (b) After the airplane has stalled, as defined in SC23.201(b) it 
must be possible to regain wings level flight by normal use of the 
flight controls but without increasing thrust and without--
    (1) Excessive loss of altitude;
    (2) Undue pitch up;
    (3) Uncontrollable tendency to spin;
    (4) Exceeding a bank angle of 60 degrees in the original 
direction of the turn or 30 degrees in the opposite direction in the 
case of turning flight stalls;
    (5) Exceeding a bank angle of 90 degrees in the original 
direction of the turn or 60 degrees in the opposite direction in the 
case of accelerated turning stalls; and
    (6) Exceeding the maximum permissible speed or allowable limit 
load factor.
    (c) Compliance with the requirements of this section must be 
shown under the following conditions:
    (1) Wing flaps: Retracted, fully extended and each intermediate 
normal operating position;
    (2) Landing gear: Retracted and extended;
    (3) Power: Power off and 75 percent maximum continuous thrust. 
If the thrust-to-weight ratio at 75 percent maximum continuous 
thrust results in extremely nose-high attitudes, the test may be 
accomplished with the power required for level flight in the landing 
configuration at maximum landing weight and a speed of 1.4 VSO, 
but the power may not be less than 50 percent of maximum continuous 
thrust;
    (4) Trim: The airplane trimmed at a speed as near 1.5 VS1 
as practicable.

SC23.207  Stall Warning

    (a) There must be a clear and distinctive stall warning, with 
the flaps and landing gear in any normal position, in straight and 
turning flight.
    (b) The stall warning may be furnished either through the 
inherent aerodynamic qualities of the airplane or by a device 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.
    (c) During the stall tests required by SC23.201(b) and 
SC23.203(a)(1), the stall warning must begin at a speed exceeding 
the stalling speed by a margin of not less than 5 knots and must 
continue until the stall occurs.
    (d) When following the procedures of SC23.1585, the stall 
warning must not occur during a takeoff with all engines operating, 
a takeoff continued with one engine inoperative, or during an 
approach to landing.
    (e) During the stall tests required by SC23.203(a)(2), the stall 
warning must begin sufficiently in advance of the stall for the 
stall to be averted by pilot action taken after the stall warning 
first occurs.
    (f) An artificial stall warning may be mutable, provided that it 
is armed automatically during takeoff and re-armed automatically in 
the approach configuration.

Ground Handling Characteristics

SC23.231  Longitudinal Stability and Control

    The airplane may have no uncontrollable tendency to nose over in 
any reasonably expected operating condition, including rebound 
during landing or takeoff. Wheel brakes must operate smoothly and 
may not induce any undue tendency to nose over.

SC23.233  Directional Stability and Control

    (a) A 90 degree cross-component of wind velocity, demonstrated 
to be safe for taxiing, takeoff and landing must be established and 
must be not less than 0.2 VSO.
    (b) The airplane must be satisfactorily controllable in power-
off landings at normal landing speed, without using brakes or engine 
thrust to maintain a straight path until the speed has decreased to 
at least 50 percent of the speed at touchdown.
    (c) The airplane must have adequate directional control during 
taxiing.

SC23.235  Operation on Unpaved Surfaces

    The airplane must be demonstrated to have satisfactory 
characteristics and the shock-absorbing mechanism must not damage 
the structure of the airplane when the airplane is taxied on the 
roughest ground that may reasonably be expected in normal operation 
and when takeoffs and landings are performed on unpaved runways 
having the roughest surface that may reasonably be expected in 
normal operation.

Miscellaneous Flight Requirements

SC23.251  Vibration and Buffeting

    There must be no vibration or buffeting severe enough to result 
in structural damage and each part of the airplane must be free from 
excessive vibration, under any appropriate speed and power 
conditions up to VD/MD. In addition, there must be no 
buffeting in any normal flight condition severe enough to interfere 
with the satisfactory control of the airplane or cause excessive 
fatigue to the flight crew. Stall warning buffeting within these 
limits is allowable.

SC23.253  High Speed Characteristics

    The following speed increase and recovery characteristics must 
be met--
    (a) 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 speed up 
to VMO/MMO. These conditions and characteristics include 
gust upsets, inadvertent control movements, low stick force gradient 
in relation to control friction, leveling off from climb and descent 
from Mach limit to airspeed limit altitude.
    (b) Allowing for pilot reaction time after occurrence of the 
effective inherent or artificial speed warning specified in 
Sec. 23.1303, it must be shown that the airplane can be recovered to 
a normal attitude and its speed reduced to VMO/MMO 
without--
    (1) Exceptional piloting strength or skill;
    (2) Exceeding VD/MD, the maximum speed shown under 
SC23.251, or the structural limitations; or
    (3) Buffeting that would impair the pilot's ability to read the 
instruments or to control the airplane for recovery.
    (c) There may be no control reversal about any axis at any speed 
up to the maximum speed shown under SC23.251. Any reversal of 
elevator control force or tendency of the airplane to pitch, roll, 
or yaw must be mild and readily controllable, using normal piloting 
techniques.

4. Operating Procedures and Information

    Instead of compliance with the sections contained in subpart G 
of part 23, the following sections apply:

*SC23.1501  General

    (a) Each operating limitation specified in SC23.1505 through 
SC23.1527 and other limitations and information necessary for safe 
operation must be established.
    (b) The operating limitations and other information necessary 
for safe operation must be made available to the crew members as 
prescribed in SC23.1541 through SC23.1589.

SC23.1505  Airspeed Limitations

    The maximum operating limit speed (VMO/MMO airspeed or 
Mach number, whichever is critical at a particular altitude) must be 
established as 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/MC and so that it is 
sufficiently below VD/MD and the maximum speed shown under 
SC23.251 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 the maximum speed shown 
under SC23.251 may not be less than the speed margin established 
between VC/MC and VD/MD under Sec. 23.335(b), or 
the speed margin found necessary in the flight tests conducted under 
SC23.253.

SC23.1507  Operating Maneuvering Speed

    The maximum operating maneuvering speed VO must be 
established as an operating limitation, where VO must not be 
greater than the VSN established in Sec. 23.335(c).

SC23.1511  Flap Extended Speed

    (a) The flap extended speed VFE must be established so that 
it is--
    (1) Not less than the minimum value of VF allowed in 
Sec. 23.345(b); and
    (2) Not more than VF established under Sec. 23.345 (a), 
(c), and (d).
    (b) Additional combinations of flap setting, airspeed, and 
engine thrust may be established if the structure has been proven 
for the corresponding design conditions.

SC23.1513  Minimum Control Speed

    The minimum control speed(s) VMC, determined under SC23.149 
(b) and (c) must be established as an operating limitation(s).

SC23.1519  Weight and Center of Gravity

    The weight and center of gravity ranges, determined under 
SC23.23 must be established as operating limitations.

SC23.1521  Powerplant Limitations

    (a) General. The powerplant limitations prescribed in this 
section must be established so that they do not exceed the 
corresponding limits for which the engines are type certificated. In 
addition, other powerplant limitations used in determining 
compliance with this part must be established.
    (b) Takeoff operation. The powerplant takeoff operation must be 
limited by--
    (1) The maximum rotational speed (rpm);
    (2) The maximum allowable gas temperature;
    (3) The maximum allowable oil temperature; and
    (4) The time limit for the use of the thrust corresponding to 
the limitations established in paragraphs (1) and (2) of this 
special condition.
    (c) Continuous operation. The continuous operation must be 
limited by--
    (1) The maximum rotational speed (rpm);
    (2) The maximum allowable gas temperature; and
    (3) The maximum allowable oil temperature.
    (d) Fuel designation. The fuel designation(s) must be 
established so that it is not less than that required for the 
operation of the engines within the limitations in paragraphs (b) 
and (c) of this section.
    (e) Ambient temperature. Ambient temperature limitations must be 
established as the maximum ambient atmospheric temperature at which 
compliance with the cooling provisions of Secs. 23.1041 through 
23.1045 is shown.

SC23.1523  Minimum Flight Crew

    The minimum flight crew must be established so that it is 
sufficient for safe operation considering--
    (a) The workload on individual crew members;
    (b) The accessibility and ease of operation of necessary 
controls by the appropriate crew member; and
    (c) The kinds of operation authorized under SC23.1525.

SC23.1525  Kinds of Operation

    The kinds of operation (such as VFR, IFR, day or night) and the 
meteorological conditions (such as icing) to which the operation of 
the airplane is limited or from which it is prohibited, must be 
established appropriate to the installed equipment.

SC23.1527  Maximum Operating Altitude

    (a) The maximum altitude up to which operation is allowed, as 
limited by flight, structural, powerplant, functional, or equipment 
characteristics, must be established.
    (b) A maximum operating altitude limitation of not more than 
25,000 feet must be established for pressurized airplanes, unless 
compliance with Sec. 23.775(e) is shown.

SC23.1529  Instructions for Continued Airworthiness

    The applicant must prepare Instructions for Continued 
Airworthiness in accordance with Appendix G that are acceptable to 
the FAA. The instructions may be incomplete at type certification if 
a program exists to ensure their completion prior to the delivery of 
the first airplane.

Markings and Placards

SC23.1541  General

    (a) The airplane must contain--
    (1) The markings and placards specified in SC23.1545 through 
SC23.1567; and
    (2) Any additional information, instrument markings and placards 
required for the safe operation if it has unusual design, operating, 
or handling characteristics.
    (b) Each marking and placard prescribed in paragraph (a) of this 
section--
    (1) Must be displayed in a conspicuous place; and
    (2) May not be easily erased, disfigured or obscured.

SC23.1543  Instrument Markings: General

    For each instrument--
    (a) When markings are on the cover glass of the instrument, 
there must be means to maintain the correct alignment of the glass 
cover with the face of the dial;
    (b) Each arc and line must be wide enough and located to be 
clearly visible to the pilot; and
    (c) All related instruments must be calibrated in compatible 
units.

SC23.1545  Airspeed Indicator

    Each airspeed indicator must be marked as follows:
    (a) For the flap operating range, a white arc with the lower 
limit at VSO at the maximum weight and the upper limit at the 
flaps extended speed VFE established under SC23.1511.
    (b) A maximum allowable airspeed indication showing the 
variation of VMO/MMO with altitude or compressibility 
limitations (as appropriate), or a radial red line marking for 
VMO/MMO must be made at the lowest value of VMO/
MMO established for any altitude up to the maximum operating 
altitude for the airplane.

SC23.1547  Magnetic Direction Indicator

    (a) A placard meeting the requirements of this section must be 
installed on or near the magnetic direction indicator.
    (b) The placard must show the calibration of the instrument in 
level flight with the engines operating.
    (c) The placard must state whether the calibration was made with 
radio receivers on or off.
    (d) Each calibration reading must be in terms of magnetic 
headings in not more than 30 degree increments.
    (e) If a magnetic non-stabilized direction indicator can have a 
deviation of more than 10 degrees caused by the operation of 
electrical equipment, the placard must state which electrical loads, 
or combination of loads, would cause a deviation of more than 10 
degrees when turned on.

SC23.1549  Powerplant Instruments

    For each required powerplant instrument, as appropriate to the 
type of instruments--
    (a) Each maximum and, if applicable, minimum safe operating 
limit must be marked with a red radial or a red line;
    (b) Each normal operating range must be marked with a green arc 
or green line not extending beyond the maximum and minimum safe 
limits;
    (c) Each takeoff and precautionary range must be marked with a 
yellow arc or a yellow line; and
    (d) Each engine range that is restricted because of excessive 
vibration stresses must be marked with red arcs or red lines.

*SC23.1551  Oil Quantity Indicator

    Each oil quantity indicator must be marked in sufficient 
increments to indicate readily and accurately the quantity of oil.

SC23.1553  Fuel Quantity Indicator

    A red radial line must be marked on each indicator at the 
calibrated zero reading, as specified in Sec. 23.1337(b)(1).

SC23.1555  Control Markings

    (a) Each cockpit control, other than primary flight controls and 
simple push-button type starter switches, must be plainly marked as 
to its function and method of operation.
    (b) Each secondary control must be suitably marked.
    (c) For powerplant fuel controls--
    (1) Each fuel tank selector control must be marked to indicate 
the position corresponding to each tank and to each existing 
crossfeed position;
    (2) If safe operation requires the use of any tanks in a 
specific sequence, that sequence must be marked on or near the 
selector for those tanks;
    (3) The conditions under which the full amount of usable fuel in 
any restricted usage fuel tank can safely be used must be stated on 
a placard adjacent to the selector valve for that tank; and
    (4) Each valve control must be marked to indicate the position 
corresponding to each engine controlled.
    (d) Usable fuel capacity must be marked as follows:
    (1) The usable fuel capacity available at each selector control 
position must be indicated near the selector control.
    (e) For accessory, auxiliary and emergency controls--
    (1) The landing gear indicator required by Sec. 23.729 must be 
marked so that the pilot can, at any time, ascertain that the wheels 
are secured in the extreme positions; and
    (2) Each emergency control must be red and must be marked as to 
method of operation. No control other than an emergency control 
shall be this color.

SC23.1557  Miscellaneous Markings and Placards

    (a) Baggage and cargo compartments and ballast location. Each 
baggage and cargo compartment, and each ballast location, must have 
a placard stating any limitations on contents, including weight, 
that are necessary under the loading requirements.
    (b) Fuel and oil filler openings. The following apply--
    (1) Fuel filler openings must be marked at or near the filler 
cover with--
    (i) The words ``Jet Fuel''; and
    (ii) The permissible fuel designations, or references to the 
Airplane Flight Manual (AFM) for permissible fuel designations.
    (iii) For pressure fueling systems, the maximum permissible 
fueling supply pressure and the maximum permissible defueling 
pressure.
    (2) Oil filler openings must be marked at or near the filler 
cover with--
    (i) The word ``Oil''; and
    (ii) The permissible oil designation, or references to the 
Airplane Flight Manual (AFM) for permissible oil designations.
    (c) Emergency exit placards. Each placard and operating control 
for each emergency exit must be red. A placard must be near each 
emergency exit control and must clearly indicate the location of 
that exit and its method of operation.
    (d) The system voltage of each direct current installation must 
be clearly marked adjacent to its external power connection.

SC23.1559  Operating Limitations Placard

    (a) There must be a placard in clear view of the pilot stating--
    (1) That the airplane must be operated in accordance with the 
approved Flight Manual; and
    (2) The certificated category to which the placards apply.
    (b) There must be a placard in clear view of the pilot that 
specifies the kind of operations to which the operation of the 
airplane is limited or from which it is prohibited under SC23.1525.

SC23.1561  Safety Equipment

    (a) Safety equipment must be plainly marked as to method of 
operation.
    (b) Stowage provisions for required safety equipment must be 
marked for the benefit of occupants.

SC23.1563  Airspeed Placards

    There must be an airspeed placard in clear view of the pilot and 
as close as practicable to the airspeed indicator. This placard must 
list--
    (a) The design maneuvering speed, VO; and
    (b) The maximum landing gear operating speed, VLO;
    (c) The maximum value of the minimum control speed, VMC 
(one-engine inoperative), determined under SC23.149 (b) and (c).

SC23.1567  Flight Maneuver Placard

    There must be a placard in clear view of the pilot--
    (a) Listing the control actions for recovery from spinning 
maneuvers; and
    (b) Stating that recovery must be initiated when spiral 
characteristics appear, or after not more than six turns or not more 
than any greater number of turns for which the airplane has been 
certificated.

Airplane Flight Manual

SC23.1581  General

    (a) An FAA-Approved Airplane Flight Manual must be furnished 
with each airplane and it must contain the following--
    (1) Information required by SC23.1583 through SC23.1589.
    (2) Other information that is necessary for safe operation 
because of design, operating or handling characteristics.
    (3) Further information necessary to comply with the relevant 
operating rules.
    (b) Each part of the Airplane Flight Manual containing 
information prescribed in SC23.1583 through SC23.1589 must be 
approved, segregated, identified, and clearly distinguished from 
each unapproved part of the Airplane Flight Manual.
    (c) The units used in the Airplane Flight Manual must be the 
same as those marked on the appropriate instruments and placards.
    (d) All Airplane Flight Manual operational airspeeds must, 
unless otherwise stated, be presented as indicated airspeeds.
    (e) Provisions must be made for stowing the Airplane Flight 
Manual in a suitable fixed container that is readily accessible to 
the pilot.
    (f) Each Airplane Flight Manual must contain a means for 
recording the incorporation of revisions and/or amendments.

SC23.1583  Operating Limitations

    The Airplane Flight Manual must contain operating limitations 
determined under the applicable regulations, including the 
following:
    (a) Airspeed limitations.
    (1) Information necessary for the marking of the airspeed limits 
on the indicator as required in SC23.1545, and the significance of 
each of those limits and of the color coding used on the indicator.
    (2) The speeds VMC, VO, VLE, and VLO and 
their significance.
    (b) Powerplant limitations.
    (1) Limitations required by SC23.1521.
    (2) Explanation of the limitations marking the instruments 
required by SC23.1549 through SC23.1553.
    (c) Weight.
    (1) The maximum weight; and
    (2) The maximum landing weight, if the design landing weight 
selected by the applicant is less than the maximum weight.
    (3) The maximum takeoff weight for each airport altitude and 
ambient temperature within the range selected by the applicant not 
exceeding the weight at which the airplane complies with the climb 
requirements of SC23.63.
    (4) The maximum landing weight for each airport altitude and 
ambient temperature within the range selected by the applicant not 
exceeding the weight at which the airplane complies with the climb 
requirements of SC23.63(b)(2).
    (5) The maximum zero fuel weight, where relevant.
    (d) Center of gravity. The established center of gravity limits.
    (e) Maneuvers. The following authorized maneuvers, appropriate 
airspeed limitations, and unauthorized maneuvers, as prescribed in 
this section:
    (1) A list of approved acrobatic flight maneuvers demonstrated 
in the type flight tests, together with recommended entry speeds and 
any other associated limitations.
    (2) Spin recovery procedure established to show compliance with 
SC23.151(d).
    (f) Maneuver load factor. The positive and negative limit load 
factors in g's.
    (g) Minimum flight crew. The number and functions of the minimum 
flight crew determined under SC23.1523.
    (h) Kinds of operation. A list of the kinds of operation to 
which the airplane is limited or from which it is prohibited under 
SC23.1525, and also a list of installed equipment that affects any 
operating limitation and identification as to the equipment's 
required operational status for the kinds of operation for which 
approval has been granted.
    (i) Maximum operating altitude. The maximum altitude established 
under SC23.1527.
    (j) Allowable lateral fuel loading. The maximum allowable 
lateral fuel loading differential, if less than the maximum 
possible.
    (k) Baggage and cargo loading. The following information for 
each baggage and cargo compartment or zone--
    (1) The maximum allowable load; and
    (2) The maximum intensity of loading.
    (l) Systems. Any limitations on the use of airplane systems and 
equipment.
    (m) Ambient temperatures. Where appropriate, maximum and minimum 
ambient air temperatures for operation.
    (n) Smoking. Any restrictions on smoking in the airplane.
    (o) Types of surface. A statement of the types of surface on 
which operations may be conducted must be provided.

SC23.1585  Operating Procedures

    Information concerning normal, abnormal (if applicable) and 
emergency procedures, and other pertinent information necessary for 
safe operation and the achievement of the scheduled performance, 
must be furnished, including--
    (a) An explanation of significant or unusual flight or ground 
handling characteristics.
    (b) The maximum demonstrated values of crosswind for takeoff and 
landing and procedures and information pertinent to operations in 
crosswinds.
    (c) Procedures, speeds, and configuration(s) for making a normal 
takeoff in accordance with SC23.51 and SC23.53 and the subsequent 
climb in accordance with SC23.65 and SC23.69.
    (d) Procedures for abandoning a takeoff due to engine failure or 
other cause.
    (e) A recommended speed for flight in rough air. This speed must 
be chosen to protect against the occurrence, as a result of gusts, 
of structural damage to the airplane and loss of control (for 
example, stalling).
    (f) Procedures, speeds, and configuration(s) for making a normal 
approach and landing in accordance with SC23.73 and SC23.75 and a 
transition to the balked landing condition.
    (g) Procedures for restarting any engine in flight, including 
the effects of altitude.
    (h) Procedures and speeds for continuing a takeoff following 
engine failure and the conditions under which takeoff can safely be 
continued, or a warning against attempting to continue the takeoff.
    (i) Procedures, speeds, and configurations for continuing a 
climb following engine failure, after takeoff in accordance with 
SC23.67 and en route in accordance with SC23.69.
    (j) Procedures, speeds, and configuration(s) for making an 
approach and landing with one engine inoperative.
    (k) Procedures, speeds, and configuration(s) for making a balked 
landing with one engine inoperative and the conditions under which a 
balked landing can safely be performed or a warning against 
attempting a balked landing.
    (l) The VSSE determined in SC23.149.
    (m) 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.
    (n) 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.
    (o) Information on the total quantity of usable fuel for each 
fuel tank and the effect on the unusuable fuel quantity as a result 
of a failure of any pump, must be furnished.
    (p) Procedures for the safe operation of the airplane's systems 
and equipment, both in normal use and in the event of malfunction, 
must be furnished.

SC23.1587  Performance Information

    Unless otherwise prescribed, the following information must be 
furnished over the altitude and temperature ranges required by 
SC23.45(b)--
    (a) The stalling speeds VSO, and VS1 with the landing 
gear and wing flaps retracted, determined at maximum weight under 
SC23.49 and the effect on these stalling speeds of angles of bank up 
to 60 degrees.
    (b) The takeoff distance, determined under SC23.53 and the type 
of runway surface for which it is valid.
    (c) The steady rate and gradient of climb with all engines 
operating, determined under SC23.69(a).
    (d) The landing distance, determined under SC23.75, and the type 
of runway surface for which it is valid.
    (e) The effect on takeoff and landing distances of operation on 
other than smooth hard surfaces, when dry, determined under 
SC23.45(g).
    (f) The effect on takeoff and landing distances of runway slope 
and 50 percent of the headwind component and 150 percent of the 
tailwind component.
    (g) The steady rate and gradient of climb/descent with one 
engine inoperative, determined under SC23.69(b).
    (h) The steady gradient of climb/descent, determined under 
SC23.66.

SC23.1589  Loading Information

    The following loading information must be furnished:
    (a) The weight and location of each item of equipment that can 
easily be removed, relocated, or replaced and that is installed when 
the airplane was weighed under SC23.25.
    (b) Appropriate loading instructions for each possible loading 
condition between the maximum and minimum weights established under 
SC23.25, to facilitate the center of gravity remaining within the 
limits established under SC23.23.

5. 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 SC23.141 through 
SC23.253 and special condition 4 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 condition 4.

    Issued in Kansas City, Missouri, on January 31, 1994.
Barry D. Clements,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 94-3620 Filed 2-17-94; 8:45 am]
BILLING CODE 4910-13-M