viii Table of Contents (continued)
Paragraph Page No.
Section 2. Operating Limitations [Reserved] _________________________________ 290 Section 3. Markings and Placards [Reserved] ________________________________ 290 Section 4. Airplane Flight Manual __________________________________________ 290
224. General - § 25.1581. _______________________________________________ 290 [225. - 227.] [Reserved] _________________________________________________ 290 Chapter 8 - Airworthiness: Miscellaneous Items__________________________________ 291
228. Design and Function Of Artificial Stall Warning and Identification Systems. __ 291
229. Reduced and Derated Power or Thrust Takeoff Operations. ________________ 295
230. Runway Gradients Greater Than ± 2 Percent. ___________________________ 296
231. Criteria For Approval Of Steep Approach To Landing. ____________________ 297
232. Takeoff and Landing On Unpaved Runways. ____________________________ 300
233. Accounting for Performance Effects of Minor Design Changes and Configuration Deviation List (CDL) Items. _______________________________________________ 304
234. Configuration Deviation List. ________________________________________ 305
235. Spare Engine Pod. _________________________________________________ 307
236. Authorization For Ferry Flight With One Engine Inoperative - § 91.611. ______ 307
237. Instrument Landing System Weather Minima. ___________________________ 308
238. Takeoff Performance Credit for Alternate Forward Center Of Gravity Limits. __ 309
239. Airplane Backing Using Reverse Thrust. _______________________________ 311
ix Table of Contents (continued) Figures Figure Page No.
Figure 3-1. Weight Tolerance Limits _____________________________________________ 7 Figure 3-2. Equivalent Weight Extrapolation ______________________________________ 9 Figure 3-3. Test Parameters That Normally Can Be Corrected _______________________ 10 Figure 3-4. Wind Profile Variation _____________________________________________ 11 Figure 11-1. Accelerate-Stop Time Delays _______________________________________ 38 Figure 11-2. Accelerate-Stop Speed vs. Distance __________________________________ 40 Figure 11-3. Anti-Skid System Response Characteristics ____________________________ 45 Figure 11-4. Anti-Skid System Response Characteristics ____________________________ 46 Figure 11-5. Anti-Skid System Response Characteristics ____________________________ 48 Figure 11-6. Instantaneous Brake Force and Peak Brake Force _____________________ 51 Figure 11-7. Anti-Skid Efficiency – Wheel Slip Relationship ________________________ 53 Figure 11-8. Substantiation of The Optimal Slip Value _____________________________ 54 Figure 13-1. Takeoff Distance On a Dry Runway __________________________________ 66 Figure 13-2. Takeoff Distance _________________________________________________ 66 Figure 13-3. Takeoff Distance On A Wet Runway _________________________________ 67 Figure 13-4. Takeoff Run _____________________________________________________ 68 Figure 13-5. Takeoff Run _____________________________________________________ 68 Figure 13-6. Clearway Profiles 69
x Table of Contents (continued) Figures Figure Page No.
Figure 14-1. Takeoff Segments & Nomenclature __________________________________ 70 Figure 14-2. Net Takeoff Flight Path ___________________________________________ 71 Figure 19-1. Landing Time Delays _____________________________________________ 83 Figure 20-1. Sample Pitch Tracking Task ________________________________________ 94 Figure 20-2. PIO Rating Criteria and Comparison To MIL Standard _________________ 95 Figure 20-3. Example of Acceptable HQ Rating For PIO Tendencies _________________ 96 Figure 26-1. Longitudinal Static Stability _______________________________________ 118 Figure 26-2. Local Reversal __________________________________________________ 119 Figure 29-1. Thrust Effect On Stall Speed ______________________________________ 129 Figure 29-2. CLMAX and Load Factor ___________________________________________ 131 Figure 29-3. CLMAX vs Weight and Flap Setting __________________________________ 132 Figure 29-4. Stall Speed vs Weight and Flap Setting ______________________________ 133 Figure 31-1. Maneuvering Characteristics at Speeds up to VMO/MMO _________________ 148 Figure 33-1. Mistrimmed Maneuvering Characteristics ____________________________ 156 Figure 181-1 Altitude Loss Versus Altitude At Go-Around Mode Initiation ____________ 269 Figure 181-2 Deviation Profile Method _________________________________________ 278 Figure 181-3 Height Loss Method _____________________________________________ 279
xi Table of Contents (continued) Tables Table Page No.
Table 170-1 Radio Line-of-Sight Distance vs. Flight Level or Altitude ________________ 221 Table 170-2 Marker Beacon System ___________________________________________ 227 Table 170-3 Classification of LF/MF Radio Beacons in U.S. National Service _________ 228 Table 170-4 Types of Aural Warnings __________________________________________ 245 Appendices Appendix Page No.
Appendix 1 _______________________________________________________________ A1-1 Acronyms, Abbreviations, Symbols, and Definitions __________________________ A1-1 Appendix 2 _______________________________________________________________ A2-1 Function and Reliability Tests - § 21.35(b)(2). ________________________________ A2-1 Appendix 3 _______________________________________________________________ A3-1 Historical Development of Accelerate-Stop Time Delays _______________________ A3-1 Figure 1. Accelerate-Stop Time Delays _________________________________ A3-2 Figure 2. Accelerate-Stop Time Delays _________________________________ A3-3 Appendix 4 _______________________________________________________________ A4-1 History Of Jet Transport Performance Standards ____________________________ A4-1 Special Civil Air Regulation No. SR-422 ____________________________________ A4-2 Performance A4-5
xii Table of Contents (continued )
Appendices (continued) Appendix Page No.
Airplane Flight Manual _________________________________________________ A4-13 Operating Rules ______________________________________________________ A4-14 Special Civil Air Regulation No. SR-422A __________________________________ A4-17 Performance _________________________________________________________ A4-23 Airplane Flight Manual _________________________________________________ A4-33 Operating Rules ______________________________________________________ A4-34 Special Civil Air Regulation No. SR-422B __________________________________ A4-38 Performance _________________________________________________________ A4-41 Airplane Flight Manual _________________________________________________ A4-53 Operating Rules ________________________________ ________________________________ __ A4-53 Appendix 5 _______________________________________________________________ A5-1 FAA Handling Qualities Rating Method (HQRM) ____________________________ A5-1 Figure 1. Overall HQRM Process _____________________________________ A5-2 Figure 2. Handling Qualities Ratings ___________________________________ A5-2 Figure 3. Sample Tasks for Evaluating Airplane Handling Qualities __________ A5-4 Figure 4. Probability of Occurrence Guidelines ___________________________ A5-5 Figure 5. Flaps UP Flight Envelopes ___________________________________ A5-7 Figure 6. Flaps DOWN Flight Envelopes _______________________________ A5-9 Figure 7. Combining Values ________________________________________ A5-10 Figure 8. Probability Guidelines to Determine HQ Requirements ___________ A5-11 Figure 9. Minimum HQ Requirements A5-12
xiii Table of Contents (continued)
Appendices (continued) Appendix Page No.
Appendix 6 _______________________________________________________________ A6-1 Correction Of Air Minimum Control Speed To Standard Conditions ____________ A6-1 Theoretical Basis _______________________________________________________ A6-1 Constant Cn Method ____________________________________________________ A6-2 Graphical Method ______________________________________________________ A6-3 Equation Method _______________________________________________________ A6-6 Appendix 7 _______________________________________________________________ A7-1 Rudder Pedal Force-Limited Air Minimum Control Speed _____________________ A7-1
1 Introduction
1. Purpose.
a. This AC provides updated guidance for the flight test evaluation of transport category airplanes. These guidelines provide an acceptable means of demonstrating compliance with the pertinent regulations of Title 14, Code of Federal Regulations (14 CFR) part 25. The methods and procedures described herein have evolved through many years of flight testing of transport category airplanes and, as such, represent current certification practice. This AC is not mandatory and does not constitute a regulation. It describes acceptable means, but not the only means, for demonstrating compliance with the applicable regulation(s). The FAA will consider other methods of demonstrating compliance that an applicant may elect to present. If we become aware of circumstances that convince us that following this AC would not result in compliance with the applicable regulations, we will not be bound by the terms of this AC, and we may require additional substantiation or design changes as a basis for finding compliance. This material does not change, create any additional, authorize changes in, or permit deviations from existing regulatory requirements.
b. See Appendix 1 for a list of acronyms and abbreviations used in this AC.
2. Applicability.
These methods and procedures are provided in the interest of certification approval for use during all transport category airplane flight test certification activities. This material is not to be construed as regulatory or having a mandatory effect. The procedures set forth herein are one acceptable means of compliance with applicable sections of part 25. Any alternative means proposed by the applicant should be given due consideration. Applicants are encouraged to use their technical ingenuity and resourcefulness in order to develop more efficient and less costly methods of complying with the requirements of part 25. Since these methods and procedures are only one acceptable means of compliance, individuals should be guided by the intent of the methods provided in this AC. As deviations from the methods and procedures described in this AC may occur, FAA certification personnel will coordinate what they consider to be major deviations with the Transport Standards Staff (ANM-110) of the Transport Airplane Directorate.
If in their judgment, however, a deviation is considered to be minor, coordination with ANM- 110 may not be necessary.
3. Cancellation.
AC 25-7B, Change 1, “Flight Test Guide for Certification of Transport Category Airplanes,” dated December 7, 2011, is cancelled.
4. Background.
a. Since AC 25-7 was released on April 9, 1986, it has been the primary source of guidance for flight test methods and procedures to show compliance with the regulations contained in subpart B of part 25, which address airplane performance and handling
2 characteristics. AC 25-7 has been revised several times to reflect changes in the part 25 regulatory requirements, changes in guidance and policy, and advances in technology.
b. The first revision, AC 25-7A, updated the original AC to incorporate the policy and guidance material applicable to all sections of part 25, not just subpart B. The material related to regulations outside of subpart B superseded that contained in Order 8110.8, which was cancelled when AC 25-7A was issued.
c. Change 1 to AC 25-7A added acceptable means of compliance for the regulatory changes associated with amendments 92 and 98 to part 25.
d. AC 25-7B added acceptable means of compliance for the regulatory changes associated with amendments 108, 109, and 115 to part 25, and revised guidance for expanding takeoff and landing data for airport elevations higher than those at which flight testing was conducted.
Means of compliance associated with flight in icing conditions were removed as this material is now contained in AC 25-25.
e. Change 1 to AC 25-7B added acceptable means of compliance for the regulatory changes associated with amendment 25-135.
f. This revision, AC 25-7C, is a complete revision to reduce the number of differences from the European Aviation Safety Agency’s Flight Test Guide, provide acceptable means of compliance for the regulatory changes associated with amendments 107, 109, 113, 115, 119 and 123 to part 25, to respond to FAA and National Transportation Safety Board safety recommendations, and to provide a general update to reflect current FAA and industry practices and policies.
5. Related Publications.
Certification personnel should be familiar with FAA Order 8110.4C, “Type Certification,” and FAA Order 8100.5A, “Aircraft Certification Service Mission, Responsibilities, Relationships, and Programs.” In this AC, reference is made to other FAA ACs that provide guidance on various aspects of type certification and supplemental type certification.
3 Chapter 1 - General
1. Applicability - § 25.1. [Reserved]
2. Special Retroactive Requirements - § 25.2. [Reserved]
Chapter 2 - Flight
Section 1. General
3. Proof of Compliance - § 25.21.
a. Explanation. In an effort to provide the necessary guidelines for the flight test evaluation of transport category airplanes, without producing a cumbersome document, this AC assumes a conventional transport airplane configuration. In general, a conventional airplane configuration is one with distinct wing and fuselage elements that are joined together, aftmounted horizontal and vertical stabilizers that are attached to the fuselage, and propulsion provided either by turbojet/turbofan engines that do not provide any significant increase in lift due to their operation or engine-driven propellers. The effects of non-conventional airplane configurations (e.g., blown flaps) on the compliance methods should be evaluated and determined based on the intent of the guidelines presented for conventional airplane configurations.
(1) Section 25.21(a) - Proof of Compliance.
(a) The burden of showing compliance with the flight requirements for an airworthiness certificate or a type certificate rests with the applicant. The applicant should, at his own expense and risk, conduct such official flight tests as required by the FAA to demonstrate compliance with the applicable requirements. During the certification process, the applicant should make available the airplane, as well as all of the personnel and equipment necessary to obtain and process the required data.
(b) If the airplane flight characteristics or the required flight data are affected by weight and/or center of gravity (c.g.), the compliance data must be presented for the most critical weight and c.g. position per § 25.21(a). Unless the applicant shows that the allowable c.g. travel in one or more axes (e.g., lateral fuel imbalance) has a negligible effect on compliance with the airworthiness requirements, the applicant must substantiate compliance at the critical c.g.
(c) The gross weight and c.g. tolerances specified in paragraphs 3a(3)(b)1 and 3 are test tolerances and are not intended to allow compliance to be shown at less than critical conditions.
(d) Section 21.35(a)(3) requires that the test airplane be in conformity with its type design specifications.
1 This means that the test airplane must be in conformity with its type design specification as relates to the particular test being conducted.
2 Any deviation from conformity must be clearly shown to be of no consequence to the particular test being conducted. For example, if the slip resistant escape surface required by § 25.810(c) is not installed when conducting airplane performance and flight
5 characteristics tests, the applicant must show that its presence would have no effect on measured airplane performance and flight characteristics.
(e) Section 21.35(b)(2) requires the applicant to conduct sufficient flight testing the FAA finds necessary to determine whether there is reasonable assurance that the airplane, its components, and its equipment are reliable and function properly. Appendix 2 to this AC provides guidance for showing compliance with this requirement.
(f) Acceptable use of simulation in lieu of flight testing. It is difficult to establish guidance for using simulation in lieu of flight testing that applies in all situations. However, the following general principles can be used as guidance for determining the acceptability for using simulation in lieu of flight testing:
1 In general, flight test demonstrations are the preferred method to show compliance.
2 Simulation may be an acceptable alternative to flight demonstrations in certain situations, such as the following:
(aa) A flight demonstration would be too risky even after attempts are taken to mitigate these risks (e.g., by mock takeoffs/landings in the air at a safe altitude);
(bb) The required environmental or airplane conditions are too difficult to attain, such as in the examples listed below:
(i) validation of system safety analyses failure cases involving high crosswinds,
(ii) development of crosswind guidance for slippery runway operations; and
(iii) conditions involving minimum allowable weight where the minimum allowable weight cannot be achieved because of the weight of required test equipment.
In this case, simulation data can be used to supplement flight test data obtained at the minimum practicable test weight.
(cc) The simulation is used to augment a reasonably broad flight test program; or
(dd) The simulation is used to demonstrate repeatability, or to demonstrate performance of a specific scenario for a range of pilots.
3 Simulation Criteria. If it is agreed that a simulation will be used to establish compliance, to be acceptable for use in showing compliance with the performance and handling qualities requirements, the simulation should:
(aa) Be of a type and fidelity that is appropriate for the task. For example, is motion or an exterior view needed, or is the fidelity or customizability of an engineering simulator needed?
(bb) Be suitably validated by flight test data for the conditions of interest.
(i) This does not mean that there must be flight test data at the exact conditions of interest. The reason simulation is being used may be that it is too difficult or risky to obtain flight test data at the conditions of interest.
(ii) The level of substantiation of the simulator to flight correlation should be commensurate with the level of compliance (i.e., the closer the case is to being noncompliant, the higher the required fidelity of the simulation).
(cc) Be conducted in a manner appropriate to the case and conditions of interest.
(i) If closed-loop responses are important, the simulation should be piloted by a human pilot.
(ii) For piloted simulations, the controls/displays and cues should be substantially equivalent to what would be available in the real airplane (unless it is determined that not doing so would provide added conservatism).
(2) Section 25.21(c) - Proof of Compliance (Altitude Effect on Flight Characteristics).
(a) Any of the flying qualities affected by altitude, including controllability, stability, trim, and stall characteristics, must be investigated at the most adverse altitude conditions approved for operations.
(b) Consideration should be given in the test program to any aerodynamic control system changes that occur with changes in altitude (e.g., maximum control surface displacement or auto slats that may be inhibited by Mach number above a specific altitude).
(3) Section 25.21(d) - Proof of Compliance (Flight Test Tolerances).
(a) To allow for variations from precise test values, acceptable tolerances during flight testing must be maintained. The purpose of these tolerances is to allow for small variations in flight test values of certain variables from the targeted value. They are not intended for compliance tests to be planned for other than the critical condition, nor are they to be considered as an allowable measurement error.
(b) Where variation in the parameter for which a tolerance is allowed will have an effect on the results of the test, the results should be corrected to the most critical value of that parameter within the approved operating envelope. If such a correction is impossible or