Section 6. STALLS
29. STALL TESTING .
a. The applicable Federal Aviation Regulations (FAR) are as follows:
Section 25.21(c) Proof of Compliance Section 25.103 Stalling Speed Section 25.143 Controllability and Maneuverability (General) Section 25.201 Stall Demonstration Section 25.203 Stall Characteristics Section 25.207 Stall Warning
b. Explanation.
(1) The purpose of stall testing is threefold:
(i) To define the minimum inflight airspeeds and how they vary with weight, altitude, and airplane configuration (stall speeds).
(ii) To demonstrate that handling qualities are adequate to allow a safe recovery from the highest angle of attack attainable in normal flight (stall characteristics).
(iii) To determine that there is adequate pr e-stall warning (either aerodynamic or artificial) to allow the pilot time to recover from any probable high angle of attack condition without inadvertently stalling the airplane.
(2) During this testing , the angle of attack should be increased at least to the point where the following two conditions are satisfied:
(i) Attainment of an angle of attack measurably greater than that for maximum lift, except when the stall is defined by a stall identification device (e.g., stick pusher).
(ii) Clear indication to the pilot through the inherent flight characteristics or stall identification device (e.g., stick pusher) that the airplane is stalled.
(3) The airplane is considered to be fully stalled when any one or a combination of the characteristics listed below occurs to give the pilot a clear and distinctive indication that he should stop any further increase in angle of attack, at which time recovery should be initiated using normal techniques. The stall speed is defined as the minimum speed reached during the maneuver, except for those airplanes that require stall identification devices (see paragraph 29b(3)(iv), below).
(i) The pitch control reaches the aft stop and is held full aft for two seconds, or until the pitch attitude stops increasing, whichever occurs later. In the case of turning flight stalls, recovery may be initiated once the pitch control reaches the aft stop when accompanied by a rolling motion that is not immediately controllable (provided the rolling motion complies with § 25.203(c)).
(ii) An uncommanded, distinctive and easily recognizable nose down pitch that cannot be readily arrested. This nose down pitch may be accompanied by a rolling motion that is not immediately controllable, provided that the rolling motion complies with § 25.203(b) or (c), as appropriate.
(iii) The airplane demonstrates an unmistakable, inherent aerodynamic warning of a magnitude and severity that is a strong and effective deterrent to further speed reduction. This deterrent level of aerodynamic
warning (i.e., buffet) must be of a much greater magnitude than the initial buffet ordinarily associated with stall warning. An example is a large transport airplane that exhibits “deterrent buffet” with flaps up and is characterized by an intensity that inhibits reading cockpit instruments and would require a strong determined effort by the pilot to increase the angle of attack any further.
(iv) The activation point of a stall identification device that is a strong and effective deterrent to further speed reduction. Paragraph 228 of this AC presents guidance material for demonstrating compliance of stall identification systems with the regulatory requirements of Part 25 of the FAR.
NOTE: The regulatory requirements of § 25.201(d) define the stalled condition as occurring when the airplane has reached an angle of attack measurably greater than that for maximum lift. The related stall speed has been defined as the minimum speed obtained in the stalling maneuver (V S, also referred to as V S MIN). This VS MIN definition has led to stall speeds sometimes being defined at excessively low load factors, with pilot objectivity and flying technique having considerable influence over the results. The subsequent effect on operating speeds can then lead to inconsistencies between similarly configured airplane designs and result in inadequate maneuver margins.
Consequently, applicants are encouraged to use 1-g stall speeds that reflect the ability of the wing-generated lift to support the weight of the airplane in 1-g flight. These 1-g stall speeds may be used as the reference datum for regulatory compliance through an equivalent safety finding. The FAA is in the process of amending the stall speed requirements to incorporate the 1-g stall speed methodology (ref. NPRM 95-17). Upon adoption of the final 1-g stall speed rule, further revisions to the guidance material in this AC will be proposed. Details of the 1-g stall speed regulatory equivalencies and the equivalent safety finding process are contained in Appendix 5.
(4) It should be recognized that the point at which the airplane is considered stalled may vary, depending on the airplane configuration (e.g., flaps, gear, center of gravity, and gross weight). In any case, the angle of attack must be increased until one or more of these characteristics is reached for all likely combinations of variables.
c. Stall Speeds .
(1) Background . Since many of the regulations pertaining to performance and handling qualities specify trim speeds and other variables that are functions of stall speeds, it is desirable to accomplish the stall speed testing early in the program, so the data are available for subsequent testing. Because of this interrelationship between the stall speeds and other critical performance parameters, it is essential that accurate measurement methods be used.
Most standard airplane pitot-static systems have not been found to be acceptable for stall speed determination.
These tests require the use of properly calibrated instruments and usually require a separate test airspeed system, such as a trailing bomb, a trailing cone, or an acceptable nose or wing boom.
(2) Configuration .
(i) Stall speeds should be determined for all aerodynamic configurations to be certificated for use in the takeoff, en route, approach, and landing configurations.
(ii) The center of gravity positions to be used should be those that result in the highest stall speeds for each weight (forward c.g. in most cases).
(iii) Sufficient testing should be c onducted to determine the effects of weight on stall speed.
Altitude effects (compressibility, Reynolds Number) may also be considered if credit for variations in these parameters is sought by the applicant. If stall speeds are not to be defined as a function of altitude, then all stall speed testing should be conducted at a nominal altitude no lower than 1,500 ft. above the maximum approved takeoff and landing altitude. (See paragraph 29c(5)(vii) and Figures 29 -3 and 29-4.)
(3) Procedures .
(i) The airplane should be trimmed for hands-off flight at a speed 20 percent to 40 percent above the anticipated stall speed, with the engines at idle and the airplane in the prescribed configuration for which the stall speed is being determined. Then, using only the primary longitudinal control, a constant deceleration (entry rate) is maintained until one of the previously defined points that define the stall is reached. Following the stall, engine thrust may be utilized, as desired, to expedite recovery.
(ii) A sufficient number of stalls (normally six) should be accomplished at each critical combination of weight, c.g., and external configuration, varying the entry rate from approximately 0.5 knots/second to 1.5 knots/second. The intent is to obtain enough data to define the stall speed at an entry rate of 1.0 knot/second.
(See Figure 29-2.)
(iii) During the stall speed testing, the stall characteristics of the airplane must also satisfy the requirements of §§ 25.203(a) and (b).
(iv) For airplanes that have stall identification devices for which the angle of attack for activation is biased by angle of attack rate, some additional considerations are necessary. The stall speeds are normalized against an average airspeed deceleration rate, as described in paragraph 29c(5). However, stall identification systems generally activate at a specific angle of attack, biased by an instantaneous angle of attack rate. Therefore, longitudinal control manipulation by the pilot during the stall maneuver, close to the stall identification system activation point, can advance or delay its activation without appreciably affecting the average stall entry airspeed rate. To minimize scatter in the stall speed versus entry rate data, the pilot should attempt to maintain a stable angle of attack rate or pitch rate (not necessarily a fixed airspeed deceleration rate), until the stall identification system activates. The resulting time-history of angle of attack data should be smooth and without discontinuities. A cross plot of airspeed deceleration rate, as defined in paragraph 29c(5), versus angle of attack rate for all related test points, will show the general trend of this relationship for each flap setting. Any points that do not follow this general trend should not be used in establishing the stall speed.
(4) Thrust Effects on Stall Speed .
(i) Stall speeds are normally defined with the thrust levers at idle; however, it is necessary to verify by test or analysis that engine idle thrust does not affect stall speeds to an extent that they are appreciably lower than would be experienced at zero thrust. Negative thrust at the stall, which slightly increases stall speeds, is acceptable.
(ii) To determine whether thrust effects on stall speed are significant, at least three stalls should be conducted at one flap setting, with thrust set to approximately the value required to maintain level flight at 1.6 V S in the selected configuration.
(iii) These data may then be extrapolated to a zero thrust condition t o eliminate the effects of idle thrust on stall speeds (see Figure 29-5). If the difference between idle thrust and zero thrust stall speed is 0.5 knots or less, the effect may be considered insignificant.
(iv) The effects of engine power on stall spe eds for a turbopropeller airplane can be evaluated in a similar manner. Stall speed flight tests should be accomplished with throttles closed and the propellers in the takeoff position. Engine torque, engine r.p.m., and estimated propeller efficiency can be used to predict the thrust associated with this configuration.
(5) Data Reduction and Presentation . The following is an example of how the data obtained during the stall speed testing may be reduced to standard conditions. Other methods have been found acceptable.
(i) Indicated airspeed from the flight test airspeed system is recorded throughout the stall, and these values are corrected to equivalent airspeed.
(ii) Stall entry rate is then defined as the slope of a straight line connecting stall speed and an airspeed 10 percent above the stall speed (see Figure 29-1).
Entry Rate = (VS-1.1 VS)/Time Difference
(iii) The airplane lift coefficient, C L, is then calculated for each test stall speed using the equation:
CL = W/qS = 295.37(W)/(V S(e)2S) Where: W = airplane test weight - lbs.
q = dynamic pressure - lbs./ft. 2 S = reference wing area - ft. 2 VS(e) = test stall speed corrected to knots equivalent airspeed.
(iv) The CL obtained for each stall is then corrected to the targeted c.g. position using the equation:
CLCG = CL[1+(MAC/lt)(CGstd -CGtest )] - ∆CLT Where: MAC = Wing mean aerodynamic chord length - inches.
lt = Effective tail length, measured between the wing 2 5 percent MAC and the horizontal stabilizer 25 percent MAC - inches.
CGstd = Forward c.g. limit at the pertinent weight - percent MAC/100 CGtest = Actual test c.g. position - percent MAC/100 ∆CLT = Change in CL due to engine thrust (if significant).
(v) For each targeted c.g. and external configuration, a plot of C LCG versus entry rate is constructed. The final stall C L is selected at an entry rate of 1.0 knot/second (see Figure 29-2).
(vi) For each final stall C L, weight, wing flap, and external configuration, a plot of stall C L versus weight is constructed (see Figure 29-3.) An initial negative slope of this plot may be caused by several factors:
(A) A decrease in CLMAX due to increasing Mach number (which increases as the stall speed goes up with weight);
(B) The fact that CLMAX is proportional to the rate of change of angle of attack, whereas the data are plotted at fixed airspeed bleed rate; and (C) Minor adverse aeroelastic effects on the wings and high lift devices as weight (and therefore speed) increases. The inflection at the right end is caused typically by a less forward c.g. limit as weight increases.
(vii) In the measurement of stall speeds, the lowest test altitude is usually dictated by flig ht test safety concerns. This test data must then be expanded to lower altitudes, and hence lower Mach numbers, to cover the operational envelope of the airplane. Since C LMAX increases as the Mach number is reduced, simple expansion of the flight test data could result in extrapolating to a higher C LMAX than tested. Expansion of C LMAX versus Mach number data is only permitted up to the highest C LMAX within the range of W/ δ’s tested.
(viii) Stalling speeds are then calculated using the equation:
VS(e) =
295.37(W) (C S)L Where: W = a series of weights chosen as the independent variable - lbs.
CL = stall CL corresponding to the chosen weight (see Figure 29-3).
S = reference wing area - ft. 2
(ix) A plot of stall speed ve rsus weight, showing each flap/gear configuration, is then constructed (see Figure 29-4).
d. Stall Characteristics .
(1) Background . Since operational pilots may not be required, or trained, to fly to an angle of attack beyond that for stall warning, any exposure to the behavior of the airplane in an actual stall would be both unexpected and unfamiliar. Therefore, to assure a safe and expeditious recovery from an unintentional stall, it should not require any unusual piloting technique to successfully demonstrate compliance with § 25.203, nor should it require exceptional skill or repeated practice by the test pilot. The behavior of the airplane during the stall and recovery must be easily controllable using normally expected pilot reactions.
(2) Configuration .
(i) Stall characteristics should be investigated with wings level and in a 30-degree banked turn, with both power on and power off in all configurations approved for normal operations.
(ii) The test configurations for stall characteri stics should include deployed deceleration devices for all flap positions, unless limitations against the use of those devices with particular flap positions are imposed.
‘Deceleration devices’ include spoilers used as airbrakes, and thrust reversers approved for inflight use. Stall demonstrations with deceleration devices deployed should normally be carried out with power off, except where deployment of the deceleration devices with power on would likely occur in normal operations (e.g., extended spoilers during landing approach).
(iii) Stall characteristics should be investigated with any systems or devices that may alter the stalling behavior of the airplane in their normal functioning mode. Unless the design of the airplane’s automatic flight control system precludes its ability to operate beyond the stall warning angle of attack, stall characteristics and the adequacy of stall warning should be evaluated when the airplane is stalled under the control of the automatic flight control system.
(iv) Power-off stalls should be conducted at flight idle for the appropriate configuration. For propeller-driven airplanes, the propeller should be set in the normal low pitch (high r.p.m.) position.
(v) For power-on stalls, thrust should be set to the v alue required to maintain level flight at a speed of 1.6 VS with flaps in the approach position, landing gear retracted, and at maximum landing weight. The approach flap position referred to is the maximum flap deflection used to show compliance with § 25.121(d), Approach Climb.
(vi) Stall characteristics testing is normally done at the aft c.g. limit, which is typically the most adverse; however, if the stall speed tests at forward c.g. indicate that marginal stall recovery characteristics may exist at forward c.g., compliance with § 25.203 should be shown for the most critical loading.
(vii) Stalls must be demonstrated up to the maximum approved operating altitude to determine if there are any adverse compressibility effects on stall characteristics. These tests should be flown with gear and flaps up at the most adverse center of gravity. Thrust may be set, as required, to maintain approximately level flight and a 1 knot/second deceleration. A slight descent rate is permissible as long as the stall occurs at approximately the maximum approved altitude. Characteristics should be checked during a wings level stall and in a 30-degree banked turn.
(viii) For airplanes that are certificated for flight into known icing conditions, stall character istics should be demonstrated with simulated ice shapes symmetrically attached to all surfaces that are not protected by anti-ice or de-icing systems. (For further guidance on approval for flight into known icing conditions, see paragraphs 231 and 232 of this AC.)
(ix) For abnormal aerodynamic configurations covered by AFM procedures, high angle of attack characteristics should be evaluated down to either stall warning, or to an angle of attack equivalent to the AFM recommended landing approach speed divided by 1.3. If adequate controllability is present at either of these conditions, it is not necessary to stall the airplane. “Adequate controllability” means that it is possible to produce and to correct pitch, roll, and yaw by unreversed use of the flight controls, and that there are no uncommanded airplane motions due to aerodynamic flow breakdown. If stall warning is used as the end point, then it should be
demonstrated that the airplane is safely controllable and maneuverable when flown at the recommended operating speed.
(x) Stall characteristics should also be demonstrated with the maximum allowable asymmetric fuel loading. Requirements are as specified in §§ 25.203(a) and (c).
(3) Procedures .
(i) The airplane should be trimmed for ha nds-off flight at a speed 20 percent to 40 percent above the stall speed, with the appropriate power setting and configuration. Then, using only the primary longitudinal control, establish and maintain a deceleration (entry rate) consistent with that specified in § 25.201(c)(1) or
25.201(c)(2), as appropriate, until the airplane is stalled. Both power and pilot selectable trim should remain constant throughout the stall and recovery (angle of attack has decreased to the point of no stall warning).
(ii) The same trim reference (for example, 1.3 V S) should be used for both the stall speeds and characteristics testing. For all stall testing, the trim speed is based on the performance stall speeds that are (or will be) shown in the AFM.
(iii) During the approach to the stall, the longitudinal control pull force should increase continuously as speed is reduced from the trimmed speed to approximately 10 percent above the stall speed; below that speed some reduction in longitudinal control force is acceptable, provided it is not sudden or excessive.
(iv) Section 25.203(b) states that “the roll occurring between the stall and the completion of the recovery may not exceed approximately 20 degrees” for level wing stalls. In level wing stalls the bank angle may exceed 20 degrees occasionally, provided that lateral control is effective during recovery.
(v) Section 25.203(c) requires the action of the airplane, following the 30 degrees bank turning stalls, “not be so violent or extreme...” such that a prompt recovery would be difficult and require more than normal piloting skill. The maximum bank angle that occurs during the recovery should not exceed approximately 60 degrees in the original direction of the turn, or 30 degrees in the opposite direction.
(vi) The intent of evaluating the 3 knot per second deceleration rate required under § 25.201(c)(2) is to demonstrate safe characteristics at higher rates of increase in angle of attack than are obtained from the 1 knot per second stalls. The specified airspeed deceleration rate, and associated angle of attack rate, should be maintained up to the point at which the airplane stalls. The maximum bank angle that occurs during the recovery should not exceed approximately 90 degrees in the original direction of the turn, or 60 degrees in the opposite direction.
(vii) For those airplanes where stall is defined by full nose-up longitudinal control for both forward and aft c.g., the time at full aft stick during characteristics testing should be not less than that used for stall speed determination. For turning flight stalls, however, recovery may be initiated once the pitch control reaches the aft stop when accompanied by a rolling motion that is not immediately controllable (provided the rolling motion complies with § 25.203(c)).
(viii) Normal use of the lateral control must produce (or correct) a roll, and normal use of the directional control must produce (or correct) a yaw in the applied direction up to the point where the airplane is considered stalled. It must be possible to prevent or recover from a stall by normal use of the controls.
(ix) If wind tunnel tests have indicated an airplane may be susceptible to deep stall penetration (i.e., that area beyond the stall angle of attack from which recovery may be difficult or impossible), substantiation should be provided that there is adequate recovery control available at, and sufficiently beyond, the stall angle of attack.
e. (Reserved)
f. Stall Warning.
(1) Explanation. The purpose of these stall warning requirements is to provide an adequate spread between warning and stall to allow the pilot time to recover without inadvertently stalling the airplane.
(2) Background . To be acceptable, a stall warning must have the following features:
(i) Distinctiveness. The stall warning indication must be clear and distinct to a degree that will ensure positive pilot recognition of an impending stall.
(ii) Timeliness. The stall warning should normally begin at a speed not less than 7 percent above the stall speed. A lesser margin may be acceptable, depending on the probability of an inadvertent stall following stall warning recognition, and how much difference there is between the speed at which the airplane stalls (stall identification), and the minimum speed allowed under § 25.103(a).
(iii) Consistency. The stall warning must be reliable and repeatable. The warning must occur with flaps and gear in all normally used positions in both straight and turning flight. The warning may be furnished naturally through the inherent aerodynamic characteristics of the airplane, or artificially by a system designed for this purpose. If artificial stall warning is provided for any airplane configuration, it must be provided for all configurations, and continue throughout the stall until the angle of attack is reduced to approximately that at which stall warning was initiated.
(iv) An artificial stall warning indication that is a solely visual device which requires attention in the cockpit, inhibits cockpit conversation or, in the event of malfunction, causes distraction that would interfere with safe operation of the airplane, is not acceptable.
(v) For airplanes that use artificial stall warning systems, paragraph 228 of this AC pres ents guidance material for demonstrating compliance with the regulatory requirements of Part 25 of the FAR.
(3) Procedures . Stall warning tests are normally conducted in conjunction with the stall testing required by §§ 25.103 (stall speeds) and 25.203 (stall characteristics).
(4) Data Acquisition and Reduction . The stall warning speed and type and quality of warning should be noted. The speed at which acceptable stall warning begins should then be compared to the stall speed as defined in paragraph (3) above to determine if the required margin exists.
g. Accelerated Stall Warning . The applicant should determine that adequate stall warning occurs in turning flight under expected conditions of flight for takeoff, en route, and approach/landing configurations at aft c.g. and heavy weight. It should be demonstrated in slow-down turns at 1.5g normal load factor, with entry rates of at least 2 knots per second, that sufficient stall warning is provided to prevent stalling when the pilot takes recovery action not less than one second after recognition of stall warning. When stall warning is provided by an artificial system, that system’s activation point should be set to the high side of its angle of attack tolerance band for this testing.
h. Maneuver Margins . The applicant should determine that adequate maneuvering capability exists prior to stall warning at V2, all-engines-operating takeoff speed (typically defined as V 2+XX kts.), final takeoff speed (§ 25.121(c)), and VREF at forward c.g. and heavy weight for each appropriate flap setting. When stall warning is provided by an artificial system, that system’s activation point should be set to the low side of its angle of attack tolerance band for this testing.
NOTE: If it can be shown that the angle of attack tolerance band of an artificial stall warning system results in no more than a ±1.0 knot variation about the stall warning speed obtained at the nominal AOA setting, that nominal setting may be used for the maneuver margin testing specified in paragraph 29h, above.
i. Reliability of Artificial Stall Warning and Stall Identification Systems . Guidance material related to the testing and approval of artificial stall warning and stall identification systems is presented in paragraph 228 of this AC.
FIGURE 29-1. STALL TEST TIME HISTORY TRIM SPEED
1.1 Vs INOSE DOWN PITCH (NOT ELEVATOR LIMITED)
SENTRY RATE * SLOPE TRIM SPEED
1.1 Vs
ELEVATOR LIMITED
TEST AIRSPEED ELEVATOR
REACHES STOP TRIM SPEED
ISTALL IDENTIFICATION
1.1 Vs SYSTEM
I SYSTEM FIRES
ENTRYRATE SLOPE / TIME FIGURE 29-2. STALL CLCG VS ENTRY RATE
FIGURE 29-3. STALL C L vs WEIGHT AND FLAP SETTING FIGURE 29-4. STALL SPEEDS vs WEIGHT AND FLAP SETTING
A B C D
INCREASING
FLAP SETTING WEIGHT FIGURE 29-5. THRUST EFFECT ON STALL C L
THRUST EFFECT
ON STALL CL
ENGINE THRUST
Section 7. GROUND AND WATER HANDLING CHARACTERISTICS
30. GENERAL.
a. Applicable Federal Aviation Regulations (FAR). The applicable regulations are §§ 25.231, 25.233, 25.235, 25.237, and 25.239 of the FAR.
b. Section 25.231 - Longitudinal Stability and Control.
(1) Explanation. Test program objectives would not be expected to demonstrate taxiing over rough surfaces at speeds high enough to approach structural design limits, nor is it expected that in the test program the airplane be landed harder or at higher sink rates than it will ever encounter in service. However, new or modified landing gear systems should be evaluated on rough surfaces that are representative of normal service, and landings should be conducted at various sink rates sufficient to identify any dangerous characteristics or tendencies. Variables to be considered are center of gravity and taxi speed. The cockpit motion dynamics during ground handling should not impede control of the airplane, and pitching motion during bounce should not create static pitch control problems or pilot induced oscillation tendencies.
(2) Procedures. Ground handling tests at speeds normally expected in service should be conducted on smooth and rough surfaces that are likely to be encountered under normal operating conditions. Particular attention should be paid to the following:
(i) Brakes. The adequacy of the brakes when maneuvering on the ground and the tendency of the brakes to cause nosing-over should be investigated. Any bad tendency will normally be exaggerated when taxiing in a strong cross or tailwind.
(ii) Seaplanes and Amphibians. The most adverse water conditions safe for taxiing, takeoff, and landing must be established. The use and limitations of reverse thrust must be determined.
c. Section 25.233 - Directional Stability and Control.
(1) Explanation. None.
(2) Procedures. Taxi, takeoff, and landing should be conducted in all configurations under normal operating conditions.
(i) There may be no uncontrollable ground-looping tendency in 90-degree crosswinds, up to a wind velocity of 20 knots or 0.2VSO, whichever is greater (except that the wind velocity need not exceed 25 knots) at any speed at which the airplane may be expected to be operated on the ground. This may be shown while establishing the 90-degree crosswind component required by § 25.237.
(ii) Landplanes must be satisfactorily controllable, without exceptional piloting skill or alertness in power-off landings at normal landing speed, without using brakes or engine
power to maintain a straight path. This may be shown during power-off landings made in conjunction with other tests.
(iii) The airplane must have adequate directional control during taxiing. This may be shown during taxiing prior to takeoffs made in conjunction with other tests.
d. Section 25.235 - Taxiing Condition. [RESERVED]
e. Section 25.237 - Wind Velocities.
(1) Explanation.
(i) Landplanes.
(A) There must be a 90-degree crosswind component established that is shown to be safe for takeoff and landing on dry runways.
(B) The airplane must exhibit satisfactory controllability and handling characteristics in 90-degree crosswinds at any ground speed at which the airplane is expected to operate.
(ii) Seaplanes and Amphibians.
(A) There must be a 90-degree crosswind component established that is shown to be safe for takeoff and landing in all water conditions that may reasonably be expected in normal operation.
(B) There must be a wind velocity established for which taxiing is safe in any direction under all water conditions that may reasonably be expected in normal operation.
(iii) Crosswind Demonstration. A 90-degree crosswind component at 10 meters (as required by § 25.21(f)) of at least 20 knots or 0.2 VSO (where VSO is for the maximum design landing weight), whichever is greater, except that it need not exceed 25 knots, must be demonstrated during type certification tests. There are two results possible:
(A) A crosswind component value may be established that meets the minimum requirements but is not considered to be a limiting value for airplane handling characteristics.
This "demonstrated" value should be included as information in the AFM.
(B) A crosswind component value may be established that is considered to be a maximum limiting value up to which it is safe to operate for takeoff and landing. This "limiting" value should be shown in the operating limitations section of the AFM.
(2) Procedures.
(i) Configuration. These tests should be conducted in the following configurations: