U.S. Department of Transportation Federal Aviation Administration Advisory Circular Subject: Flight Test Guide for Certification of Transport Category Airplanes Date: 05/04/2018 Initiated By: AIR-670 AC No: 25-7D
This advisory circular (AC) provides guidance for the flight test evaluation of transport category airplanes. This AC includes flight test methods and procedures to show compliance with the regulations contained in title 14, Code of Federal Regulations (14 CFR) part 25, subpart B, “Flight,” which address airplane performance and handling characteristics.
This revision, AC 25-7D, clarifies paragraph 23.2.4, Engine Restart Capability—§ 25.903(e);
adds paragraph 34.4, Circuit Protective Devices—§ 25.1357; and revises appendix B, Function and Reliability (F&R) Tests, of this AC. This AC has been re-formatted to use a new paragraph numbering system for improved usability.
The first change revises the means of compliance associated with demonstrating the restart capability required by § 25.903(e). The second change adds a paragraph providing guidance for flight test evaluation of compliance with the requirements for circuit protective devices. It is made in response to recommendations from the National Transportation Safety Board. The third change revises appendix B concerning F&R testing. It addresses issues that arose with F&R testing on recent certification programs where the current guidance was unclear.
If you have suggestions for improving this AC, you may use the Advisory Circular Feedback form at the end of this AC.
/Original signed by Mel Johnson/ Dr. Michael C. Romanowski Director, Policy and Innovation Division Aircraft Certification Service
CONTENTS Paragraph Page ii
Chapter 1. Introduction1-1
1.1 Purpose1-1
1.2 Applicability1-1
1.3 Cancellation1-1
1.4 Background1-1
1.5 Related Documents1-2
Chapter 2. General2-1
2.1 Applicability—§ 25.1. [Reserved]2-1
2.2 Special Retroactive Requirements—§ 25.2. [Reserved]2-1
Chapter 3. Flight: General3-1
3.1 Proof of Compliance—§ 25.213-1
3.2 Load Distribution Limits—§ 25.23. [Reserved]3-15
3.3 Weight Limits and Center of Gravity Limits—§§ 25.25 and 25.27. [Reserved]3-15
3.4 Empty Weight and Corresponding Center of Gravity—§ 25.29. [Reserved]3-15
3.5 Removable Ballast—§ 25.313-15
3.6 Propeller Speed and Pitch Limits—§ 25.333-16
Chapter 4. Flight: Performance4-1
4.1 General—§ 25.1014-1
4.2 Takeoff and Takeoff Speeds—§§ 25.105 and 25.1074-3
4.3 Accelerate-Stop Distance—§ 25.1094-16
4.4 Takeoff Path—§ 25.1114-45
4.5 Takeoff Distance and Takeoff Run—§ 25.1134-53
4.6 Takeoff Flight Path—§ 25.1154-57
4.7 Climb: General—§ 25.1174-59
4.8 Landing Climb: All-Engines-Operating—§ 25.1194-59
4.9 Climb: One-Engine-Inoperative—§ 25.1214-61
4.10 En Route Flight Paths—§ 25.1234-64
4.11 Landing—§ 25.1254-65
CONTENTS (CONTINUED) Paragraph Page iii
Chapter 5. Flight: Controllability and Maneuverability5-1
5.1 General—§ 25.1435-1
5.2 Longitudinal Control—§ 25.1455-15
5.3 Directional and Lateral Control—§ 25.1475-20
5.4 Minimum Control Speed—§ 25.1495-24
Chapter 6. Flight: Trim6-1
6.1 Trim—§ 25.1616-1
6.2 [Reserved.]6-1
Chapter 7. Flight: Stability7-1
7.1 General—§ 25.171. [Reserved]7-1
7.2 Static Longitudinal Stability and Demonstration of Static Longitudinal Stability—
§§ 25.173 and 25.1757-1
7.3 Static Directional and Lateral Stability—§ 25.1777-5
7.4 Dynamic Stability—§ 25.1817-10
Chapter 8. Flight: Stalls8-1
8.1 Stall Testing8-1
Chapter 9. Flight: Ground and Water Handling Characteristics9-1
9.1 Part 25 Regulations9-1
9.2 Longitudinal Stability and Control—§ 25.2319-1
9.3 Directional Stability and Control—§ 25.2339-1
9.4 Taxiing Condition—§ 25.235. [Reserved]9-2
9.5 Wind Velocities—§ 25.2379-2
9.6 Spray Characteristics, Control, and Stability on Water—§ 25.2399-5
Chapter 10. Flight: Miscellaneous Requirements10-1
10.1 Vibration and Buffeting—§ 25.25110-1
10.2 High Speed Characteristics—§ 25.25310-5
10.3 Out-of-Trim Characteristics—§ 25.25510-11
CONTENTS (CONTINUED) Paragraph Page iv
Chapter 11. Structure [Reserved]11-1
Chapter 12. Design and Construction: General [Reserved]12-1
Chapter 13. Design and Construction: Control Surfaces [Reserved]13-1
Chapter 14. Design and Construction: Control Systems14-1
14.1 General—§ 25.67114-1
14.2 Flap and Slat Interconnections—§ 25.70114-1
14.3 Takeoff Warning System—§ 25.703. [Reserved]14-2
Chapter 15. Design and Construction: Landing Gear15-1
15.1 Retracting Mechanism—§ 25.72915-1
15.2 Wheels—§ 25.73115-2
15.3 Tires—§ 25.73315-4
15.4 Brakes—§ 25.73515-4
15.5 Skis—§ 25.737. [Reserved]15-18
Chapter 16. Design and Construction: Floats and Hulls [Reserved]16-1
Chapter 17. Design and Construction: Personnel and Cargo Accommodations17-1
17.1 Pilot Compartment View—§ 25.77317-1
17.2 [Reserved.]17-1
Chapter 18. Design and Construction: Emergency Provisions18-1
18.1 Ditching—§ 25.80118-1
18.2 Emergency Egress Assist Means and Escape Routes—§ 25.81018-1
Chapter 19. Design and Construction: Ventilation and Heating19-1
19.1 Ventilation—§ 25.83119-1
19.2 Cabin Ozone Concentration—§ 25.832. [Reserved]19-1
19.3 Combustion Heating Systems—§ 25.833. [Reserved]19-1
Chapter 20. Design and Construction: Pressurization20-1
20.1 Pressurized Cabins—§ 25.84120-1
20.2 Tests for Pressurized Cabins—§ 25.84320-3
CONTENTS (CONTINUED) Paragraph Page v
Chapter 21. Design and Construction: Fire Protection [Reserved]21-1
Chapter 22. Design and Construction: Miscellaneous [Reserved]22-1
Chapter 23. Powerplant: General23-1
23.1 Installation—§ 25.901. [Reserved]23-1
23.2 Engines—§ 25.90323-1
23.3 Automatic Takeoff Thrust Control System—§ 25.90423-7
23.4 Propellers—§ 25.905. [Reserved]23-9
23.5 Propeller Vibration and Fatigue—§ 25.907. [Reserved]23-9
23.6 Propeller Clearance—§ 25.925. [Reserved]23-9
23.7 Propeller Deicing—§ 25.92923-9
23.8 Reversing Systems—§ 25.93323-9
23.9 Turbojet Engine Thrust Reverser System Tests—§ 25.934. [Reserved]23-12
23.10 Turbopropeller-Drag Limiting Systems—§ 25.93723-12
23.11 Turbine Engine Operating Characteristics—§ 25.93923-14
23.12 Inlet, Engine, and Exhaust Compatibility—§ 25.941. [Reserved]23-15
23.13 Negative Acceleration—§ 25.94323-15
23.14 Thrust or Power Augmentation System—§ 25.945. [Reserved]23-16
Chapter 24. Powerplant: Fuel System24-1
24.1 Unusable Fuel Supply—§ 25.95924-1
24.2 Fuel System Hot Weather Operation—§ 25.96124-3
24.3 Fuel Tank Vents and Carburetor Vapor Vents—§ 25.97524-5
Chapter 25. Powerplant: Fuel System Components25-1
25.1 Fuel Jettisoning System—§ 25.100125-1
25.2 [Reserved.]25-3
Chapter 26. Powerplant: Oil System [Reserved]26-1
Chapter 27. Powerplant: Cooling27-1
27.1 Cooling Test Procedures—§ 25.104527-1
27.2 [Reserved.]27-8
CONTENTS (CONTINUED) Paragraph Page vi
Chapter 28. Powerplant: Induction System28-1
28.1 Air Induction—§ 25.109128-1
28.2 Induction System Icing Protection—§ 25.109328-3
Chapter 29. Powerplant: Exhaust System29-1
29.1 General—§ 25.112129-1
29.2 [Reserved.]29-1
Chapter 30. Powerplant: Controls and Accessories [Reserved]30-1
Chapter 31. Powerplant: Fire Protection31-1
31.1 Drainage and Ventilation of Fire Zones—§ 25.118731-1
31.2 Fire Extinguishing Systems—§ 25.119731-1
Chapter 32. Equipment: General32-1
32.1 Equipment: Function and Installation—§ 25.130132-1
32.2 Flight and Navigation Instruments—§ 25.130332-39
32.3 Powerplant Instruments—§ 25.1305. [Reserved]32-40
32.4 Miscellaneous Equipment—§ 25.1307. [Reserved]32-40
32.5 Equipment, Systems, and Installations—§ 25.130932-40
Chapter 33. Equipment: Instruments Installation33-1
33.1 Arrangement and Visibility—§ 25.1321. [Reserved]33-1
33.2 Warning, Caution, and Advisory Lights—§ 25.1322. [Reserved]33-1
33.3 Airspeed Indicating System—§ 25.132333-1
33.4 Static Pressure Systems—§ 25.1325(d) and (e)33-4
33.5 Pitot Heat Indication Systems—§ 25.1326. [Reserved]33-5
33.6 Magnetic Direction Indicator—§ 25.1327. [Reserved]33-5
33.7 Flight Guidance System—§ 25.132933-5
Chapter 34. Equipment: Electrical Systems and Equipment34-1
34.1 General—§ 25.135134-1
34.2 Electrical Equipment and Installations—§ 25.1353. [Reserved]34-4
34.3 Distribution System—§ 25.135534-4
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