CONTENTS (CONTINUED) Paragraph Page vii
34.4 Circuit Protective Devices—§ 25.135734-4
34.5 Electrical System Tests—§ 25.136334-5
Chapter 35. Equipment: Lights35-1
35.1 Instrument Lights—§ 25.138135-1
35.2 Landing Lights—§ 25.138335-1
35.3 Position Light System Installation—§ 25.138535-1
35.4 Anti-Collision Light System—§ 25.140135-2
35.5 Wing Icing Detection Lights—§ 25.140335-3
Chapter 36. Safety Equipment [Reserved]36-1
Chapter 37. Miscellaneous Equipment37-1
37.1 Electronic Equipment—§ 25.143137-1
37.2 Equipment Standards for Oxygen Dispensing Units—§ 25.144737-2
Chapter 38. Operating Limitations and Information: General [Reserved]38-1
Chapter 39. Operating Limitations and Information: Operating Limitations [Reserved]39-1
Chapter 40. Operating Limitations and Information: Markings and Placards [Reserved]40-1
Chapter 41. Operating Limitations and Information: Airplane Flight Manual41-1
41.1 General—§ 25.158141-1
41.2 [Reserved.]41-1
Chapter 42. Airworthiness: Miscellaneous Items42-1
42.1 Design and Function of Artificial Stall Warning and Identification Systems42-1
42.2 Reduced and Derated Power or Thrust Takeoff Operations42-5
42.3 Runway Gradients Greater than ±2 Percent42-6
42.4 Criteria for Approval of Steep Approach to Landing42-8
42.5 Takeoff and Landing on Unpaved Runways42-12
42.6 Accounting for Performance Effects of Minor Design Changes and Configuration
Deviation List Items42-15
42.7 Configuration Deviation List42-16
42.8 Spare Engine Pod42-19
CONTENTS (CONTINUED) Paragraph Page viii
42.9 Authorization for Ferry Flight with One Engine Inoperative—§ 91.61142-19
42.10 Instrument Landing System Weather Minima42-20
42.11 Takeoff Performance Credit for Alternate Forward Center of Gravity Limits42-21
42.12 Airplane Backing Using Reverse Thrust42-23
Appendix A. Acronyms, Abbreviations, Symbols, and DefinitionsA-1
Appendix B. Function and Reliability (F&R) TestsB-1
Appendix C. Historical Development of Accelerate-Stop Time DelaysC-1
Appendix D. History of Jet Transport Performance StandardsD-1
Appendix E. FAA Handling Qualities Rating MethodE-1
Appendix F. Correction of Air Minimum Control Speed to Standard ConditionsF-1
Appendix G. Rudder Pedal Force-Limited Air Minimum Control SpeedG-1
CONTENTS (CONTINUED)
FIGURES Number Page ix
Figure 3-1. Equivalent Weight Extrapolation3-6
Figure 3-2. Wind Profile Variation3-9
Figure 4-1. Accelerate-Stop Time Delays4-23
Figure 4-2. Accelerate-Stop Speed versus Distance4-25
Figure 4-3. Anti-Skid System Response Characteristics: On-Off System on Dry Runway4-30
Figure 4-4. Anti-Skid System Response Characteristics: On-Off System on Wet Runway4-30
Figure 4-5. Anti-Skid System Response Characteristics: Quasi-Modulating System on
Dry Runway4-31
Figure 4-6 Anti-Skid System Response Characteristics: Quasi-Modulating System on
Wet Runway4-32
Figure 4-7. Anti-Skid System Response Characteristics: Fully Modulating System4-33
Figure 4-8. Instantaneous Brake Force and Peak Brake Force4-37
Figure 4-9. Anti-Skid Efficiency–Wheel Slip Relationship4-39
Figure 4-10. Substantiation of the Optimal Slip Value4-40
Figure 4-11. Takeoff Distance on a Dry Runway: Critical Engine Fails at VEF4-53
Figure 4-12. Takeoff Distance: All-Engines-Operating4-54
Figure 4-13. Takeoff Distance on a Wet Runway: Critical Engine Fails at VEF4-54
Figure 4-14. Takeoff Run: Critical Engine Fails at VEF4-55
Figure 4-15. Takeoff Run: All-Engines-Operating4-56
Figure 4-16. Clearway Profiles4-57
Figure 4-17. Takeoff Segments and Nomenclature4-58
Figure 4-18. Net Takeoff Flight Path4-59
Figure 4-19. Landing Time Delays4-72
Figure 5-1. Sample Pitch Tracking Task5-10
Figure 7-1. Longitudinal Static Stability7-4
Figure 7-2. Local Reversal7-5
Figure 8-1. Thrust Effect on Stall Speed8-5
Figure 8-2. CLMAX and Load Factor8-7
Figure 8-3. CLMAX versus Weight and Flap Setting8-8
CONTENTS (CONTINUED)
FIGURES Number Page x
Figure 8-4. Stall Speed versus Weight and Flap Setting8-10
Figure 10-1. Maneuvering Characteristics at Speeds up to VMO/MMO10-4
Figure 10-2. Mistrimmed Maneuvering Characteristics: Speeds Between VFC/MFC
and VDF/MDF10-13
Figure 33-1. Altitude Loss versus Altitude at Go-Around Mode Initiation33-16
Figure 33-2. Deviation Profile Method33-26
Figure 33-3. Height Loss Method33-27
Figure C-1. Accelerate-Stop Time Delays (Pre-Amendment 25-42)C-2
Figure C-2. Accelerate-Stop Time Delays (Amendment 25-42 through Amendment 25-91) ... C-3
Figure E-1. Overall HQRM ProcessE-2
Figure E-2. Sample Tasks for Evaluating Airplane Handling QualitiesE-4
Figure E-3. Probability of Occurrence GuidelinesE-5
Figure E-4. Flaps UP Flight EnvelopesE-7
Figure E-5. Flaps DOWN Flight EnvelopesE-8
Figure E-6. Combining ValuesE-9
Figure E-7. Probability Guidelines to Determine HQ RequirementsE-10
Figure F-1. Two-Engine Business JetF-4
Figure F-2. Four-Engine TransportF-4
Figure F-3. Yawing Moment—Engine and AirframeF-5
Figure F-4. Yawing Moment—Engine and Airframe at Altitude of 3,000 Feet (Test Day)F-7
Figure G-1. Rudder Force Versus WsinΦG-2
Figure G-2. Plot to Determine VMCAG-3
Figure G-3. Plot to Determine VMCA for an Amendment 25-42 AirplaneG-4
Figure G-4. Plot to Determine VMCA for Derate ThrustG-5
CONTENTS (CONTINUED) TABLES Number Page xi
Table 3-1. Weight Tolerance Limits3-4
Table 3-2. Test Parameters that Normally can be Corrected3-8
Table 5-1. PIO Rating Criteria and Comparison to MIL Standard5-11
Table 5-2. Example of Acceptable HQ Rating for PIO Tendencies5-12
Table 32-1. Radio Line-of-Sight Distance versus Flight Level or Altitude32-5
Table 32-2. Marker Beacon System32-12
Table 32-3. Classification of LF/MF Radio Beacons in U.S. National Service32-14
Table 32-4. Types of Aural Warnings32-33
Table A-1. Terms and DefinitionsA-1
Table A-2. SymbolsA-10
Table E-1. Comparison of Handling Qualities RatingsE-2
Table E-2. Minimum HQ RequirementsE-11
Table F-1. Example Data for Typical Business Jet EngineF-5
Table F-2. Example Data for Typical Business Jet Engine at Altitude of 3,000 FeetF-7
1-1 CHAPTER 1. INTRODUCTION
1.1 Purpose.
1.1.1 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.
1.1.2 See appendix A for a list of acronyms and abbreviations used in this AC.
1.2 Applicability.
1.2.1 The guidance provided in this document is directed to airplane manufacturers, modifiers, foreign regulatory authorities, and Federal Aviation Administration (FAA) certification engineers, flight test pilots, and FAA designees.
1.2.2 This material is neither mandatory nor regulatory in nature and does not constitute a regulation. It describes acceptable means, but not the only means, for demonstrating compliance with the applicable regulations. The Federal Aviation Administration will consider other methods of demonstrating compliance that an applicant may elect to present.
1.2.3 While these guidelines are not mandatory, they are derived from extensive FAA and industry experience in determining compliance with the relevant regulations. On the other hand, 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.
1.2.4 This material does not change, create any additional, authorize changes in, or permit deviations from, regulatory requirements.
1.3 Cancellation.
This AC cancels AC 25-7C, Flight Test Guide for Certification of Transport Category Airplanes, dated October 16, 2012.
1.4 Background.
1.4.1 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
1-2 handling 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.
1.4.2 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, Engineering Flight Test Guide for Transport Category Airplanes, which was cancelled when AC 25-7A was issued.
1.4.3 Change 1 to AC 25-7A added acceptable means of compliance for the regulatory changes associated with amendments 25-92 and 25-98 to part 25.
1.4.4 AC 25-7B added acceptable means of compliance for the regulatory changes associated with amendments 25-108, 25-109, and 25-115 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 25-25A, Performance and Handling Characteristics in Icing Conditions, dated October 27, 2014.
1.4.5 Change 1 to AC 25-7B added acceptable means of compliance for the regulatory changes associated with amendment 25-135.
1.4.6 AC 25-7C reduced the number of differences between the FAA and European Aviation Safety Agency flight test guides, provided acceptable means of compliance for the regulatory changes associated with amendments 25-107, 25-109, 25-113, 25-115, 25-119 and 25-123 to part 25, and included changes responding to safety recommendations from the FAA and National Transportation Safety Board.
1.5 Related Documents.
1.5.1 Orders.
The following FAA orders are related to the guidance in this AC. The latest version of each order at the time of publication of this AC is identified below. If any order is revised after publication of this AC, you should refer to the latest version for guidance, which can be downloaded from the Internet at https://www.faa.gov/regulations_policies/orders_notices/.
Order 8100.5C, Aircraft Certification – Organizational Structure and Functions, dated July 14, 2017.
Order 8110.4C, with Change 6, Type Certification, dated March 3, 2017.
1.5.2 Advisory Circulars.
The following FAA ACs are related to the guidance in this AC. The latest version of each AC at the time of publication of this AC is identified below. If any AC is revised after publication of this AC, you should refer to the latest version for guidance, which
1-3 can be downloaded from the Internet at www.faa.gov/regulations_policies/advisory_circulars.
AC 20-73A, Aircraft Ice Protection, dated August 16, 2006.
AC 20-124, Water Ingestion Testing for Turbine Powered Airplanes, dated September 30, 1985.
AC 20-131A, Airworthiness Approval of Traffic Alert and Collision Avoidance Systems (TCAS II) and Mode S Transponders, dated March 29, 1993.
AC 20-138D, with Change 2, Airworthiness Approval of Positioning and Navigation Systems, dated April 7, 2016.
AC 20-147A, Turbojet, Turboprop, Turboshaft, and Turbofan Engine Induction System Icing and Ice Ingestion, dated October 22, 2014.
AC 20-161, Aircraft Onboard Weight and Balance Systems, dated April 11, 2008.
AC 20-168, Certification Guidance for Installation of Non-Essential, Non-Required Aircraft Cabin Systems & Equipment (CS&E), dated July 22, 2010, AC 21-29D, Detecting and Reporting Suspected Unapproved Parts, dated July 12, 2016.
AC 21.101-1B, Establishing the Certification Basis of Changed Aeronautical Products, March 11, 2016.
AC 25-9A, Smoke Detection, Penetration, and Evacuation Tests and Related Flight Manual Emergency Procedures, dated January 6, 1994.
AC 25-11B, Electronic Flight Displays, dated October 7, 2014.
AC 25-12, Airworthiness Criteria for the Approval of Airborne Windshear Warning Systems in Transport Category Airplanes, dated November 2, 1987.
AC 25-13, Reduced and Derated Takeoff Thrust (Power) Procedures, dated May 4, 1988.
AC 25-15 Approval of Flight Management Systems in Transport Category Airplanes, dated November 20, 1989.
AC 25-17A, with Change 1, Transport Airplane Cabin Interiors Crashworthiness Handbook, dated May 24, 2016.
AC 25-20, Pressurization, Ventilation, and Oxygen Systems Assessment for Subsonic Flight Including High Altitude Operations, dated September 10, 1996.
AC 25-22, Certification of Transport Airplane Mechanical Systems, dated March 14, 2000.
AC 25-23, Airworthiness Criteria for Installation Approval of a Terrain Awareness and Warning System (TAWS) for Part 25 Airplanes, dated May 22, 2000.
AC 25-25A, Performance and Handling Characteristics in Icing Conditions, dated October 27, 2014.
1-4 AC 25.735-1, Brakes and Braking Systems Certification Tests and Analysis, dated April 10, 2002.
AC 25.773-1, Pilot Compartment View Design Considerations, dated January 8, 1993.
AC 25.939-1, Evaluating Turbine Engine Operating Characteristics, dated March 19, 1986.
AC 25.1309-1A, System Design and Analysis, dated June 21, 1988.
AC 25.1329-1C, with Change 1, Approval of Flight Guidance Systems, dated May 24, 2016.
AC 25.1357-1A, Circuit Protective Devices, dated October 22, 2007.
AC 25.1581-1, with Change 1, Airplane Flight Manual, dated October 16, 2012.
AC 43.13-1B, with Change 1, Acceptable Methods, Techniques, and Practices— Aircraft Inspection and Repair, dated September 27, 2001.
AC 90-100A, with Change 2, U.S. Terminal and En Route Area Navigation (RNAV) Operations, dated April 14, 2015.
AC 90-101A, with Change 1, Approval Guidance for RNP Procedures with AR, dated February 9, 2016.
AC 90-105A, Approval Guidance for RNP Operations and Barometric Vertical Navigation in the U.S. National Airspace System and in Oceanic and Remote Continental Airspace, dated March 7, 2016.
AC 91-79A, with Change 1, Mitigating the Risks of a Runway Overrun Upon Landing, dated April 28, 2016.
AC 120-28D, Criteria for Approval of Category III Weather Minima for Takeoff, Landing, and Rollout, dated July 13, 1999.
AC 120-29A, Criteria for Approval of Category I and Category II Weather Minima for Approach, dated August 12, 2002.
AC 150/5320-12C, with Change 8, Measurement, Construction, and Maintenance of Skid-Resistant Airport Pavement Surfaces, dated February 7, 2007.
2-1 CHAPTER 2. GENERAL
2.1 Applicability—§ 25.1. [Reserved]
2.2 Special Retroactive Requirements—§ 25.2. [Reserved]
3-1 CHAPTER 3. FLIGHT: GENERAL
3.1 Proof of Compliance—§ 25.21.
3.1.1 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, aft-mounted 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.
3.1.2 Section 25.21(a)—Proof of Compliance.
3.1.2.1 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.
3.1.2.2 If the airplane flight characteristics or the required flight data are affected by weight and/or center of gravity (CG), the compliance data must be presented for the most critical weight and CG position per § 25.21(a).
Unless the applicant shows that the allowable CG 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 CG.
3.1.2.3 The gross weight and CG tolerances specified in paragraphs 3.1.4.3 and
3.1.4.5 are test tolerances and are not intended to allow compliance to be shown at less than critical conditions.
3.1.2.4 Section 21.35(a)(3) requires that the test airplane be in conformity with its type design specifications. This means that the test airplane must be in conformity with its type design specification as it relates to the particular test being conducted. 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 characteristics
3-2 tests, the applicant must show that its presence would have no effect on measured airplane performance and flight characteristics.
3.1.2.5 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 B to this AC provides guidance for showing compliance with this requirement.
3.1.2.6 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:
3.1.2.6.1 In general, flight test demonstrations are the preferred method to show compliance.
3.1.2.6.2 Simulation may be an acceptable alternative to flight demonstrations in certain situations, such as the following:
1. 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);
2. The required environmental or airplane conditions are too difficult to attain, such as (1) validation of system safety analyses failure cases involving high crosswinds; (2) development of crosswind guidance for slippery runway operations; and (3) conditions involving minimum allowable weight where the minimum allowable weight cannot be achieved because of the weight of required test equipment. In case (3), simulation data can be used to supplement flight test data obtained at the minimum practicable test weight.
3. The simulation is used to augment a reasonably broad flight test program; or
4. The simulation is used to demonstrate repeatability, or to demonstrate performance of a specific scenario for a range of pilots.
3.1.2.6.3 Simulation Criteria.
If it is agreed that a simulation will be used to establish compliance, then the simulation should meet the following criteria in order to be acceptable for showing compliance with the performance and handling qualities requirements:
1. The simulation should 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?