AC 25-25A

Advisory circular · Performance and Handling Characteristics in Icing Conditions

Approved
October 27, 2014
Last reviewed
August 18, 2017
Cancels
AC25-25
Family
AC 25-25 · 2 versions
Revision
A
14 CFR parts
25

Guidance, not mandatory unless a rule or AD requires it. DRS record last changed October 23, 2026.

Show pages 55–66

Appendix E E-1 APPENDIX E. RELATED REGULATIONS AND ADVISORY CIRCULARS E.1 Regulations.

The following sections of Title 14, Code of Federal Regulations (14 CFR) part 25 are referenced in this AC. The full text of these regulations can be downloaded from the U.S. Government Printing Office e-CFR. A paper copy may be ordered from the Government Printing Office, Superintendent of Documents, Attn: New Orders, PO Box 371954, Pittsburgh, PA, 15250-7954.

Table E-1. Related Regulations 14 CFR Title § 25.21 Proof of compliance § 25.23 Load distribution limits § 25.25 Weight limits § 25.27 Center of gravity limits § 25.29 Empty weight and corresponding center of gravity § 25.31 Removable ballast § 25.33 Propeller speed and pitch limits § 25.101 Performance—General § 25.103 Stall speed § 25.105 Takeoff § 25.107 Takeoff speeds § 25.109 Accelerate-stop distance § 25.111 Takeoff path § 25.119 Landing climb: All-engines-operating § 25.121 Climb: One-engine-inoperative § 25.123 En route flight paths

Appendix E E-2 14 CFR Title § 25.125 Landing § 25.143 Controllability and Maneuverability—General § 25.145 Longitudinal control § 25.147 Directional and lateral control § 25.161 Trim § 25.171 Stability—General § 25.175 Demonstration of static longitudinal stability § 25.177 Static lateral-directional stability § 25.181 Dynamic stability § 25.201 Stall demonstration § 25.203 Stall characteristics § 25.207 Stall warning § 25.231 Longitudinal stability and control § 25.233 Directional stability and control § 25.235 Taxiing condition § 25.237 Wind velocities § 25.251 Vibration and buffeting § 25.253 High-speed characteristics § 25.255 Out-of-trim characteristics § 25.1309 Equipment, systems, and installations § 25.1329 Flight guidance system § 25.1419 Ice protection § 25.1420 Supercooled large drop icing conditions § 25.1581 Airplane Flight Manual—General

Appendix E E-3 14 CFR Title § 25.1583 Operating limitations § 25.1585 Operating procedures § 25.1587 Performance information Part 25, Appendix C Part 25, Appendix O Supercooled Large Drop Icing Conditions E.2 Advisory Circulars.

The following ACs are related to the guidance in this AC. Table E-2 identifies the latest version of each AC at the time of publication. If any AC is revised after publication of this AC, you should refer to the latest version for guidance. You can find the latest version at the FAA website.

Table E-2. Related Advisory Circulars Number Title Date AC 20-73A Aircraft Ice Protection August 16, 2006 AC 25-7C Flight Test Guide for Certification of Transport Category Airplanes October 16, 2012 AC 25.1309-1A System Design and Analysis June 21, 1988 AC 25.1329-1C Approval of Flight Guidance Systems October 27, 2014 AC 25.1419-2 Compliance with the Ice Protection Requirements of §§ 25.1419(e), (f), (g), and (h) October 27, 2009 AC 25-28 Compliance of Transport Category Airplanes with Certification Requirements for Flight in Icing Conditions October 27, 2014

Appendix F F-1 APPENDIX F. ACRONYMS Table F-1. Acronyms, Terms, and Definitions Acronym/Term Definition AC Advisory Circular ACO Aircraft Certification Office AFM Airplane Flight Manual ATTCS Automatic Takeoff Thrust Control System CAS Calibrated Airspeed CFR Code of Federal Regulations FAA Federal Aviation Administration ICTS Ice-Contaminated Tailplane Stall KIAS Knots Indicated Airspeed LWC Liquid Water Content MED Mean Effective Diameter MVD Median Volume Diameter CL Lift Coefficient CLMAX Maximum Lift Coefficient SLD Supercooled Large Drop Trim A flight condition in which the aerodynamic moment acting about the axis of interest is zero. In the absence of an external disturbance, no control input is needed to maintain the flight condition.

Appendix F F-2 Acronym/Term Definition V1 The maximum speed in the takeoff at which the pilot must take the first action (for example, apply brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance. V1 also means the minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.

V2 Takeoff Safety Speed. (The target speed to be reached by the time the airplane is 35 feet above the takeoff surface.)

V2MIN Minimum Takeoff Safety Speed VCW Crosswind Component of Wind Speed VDF/MDF Demonstrated Flight Diving Speed VEF Engine Failure Speed. The speed at which the critical engine is assumed to fail during takeoff.

VFC Maximum Speed for Stability Characteristics VFE Maximum Flaps Extended Speed VMO Maximum Operating Limit Speed VREF Landing Reference Speed VS 1-g 1-g Stall Speed. The calibrated airspeed at which aerodynamic forces alone can support the airplane in 1-g flight.

VSR Reference Stall Speed. VSR may not be less than VS 1-g. For airplanes with a device that abruptly pushes the nose down at a selected angle of attack (for example, a stick pusher), VSR may not be less than 2 knots or 2 percent, whichever is greater, above the speed at which the device operates.

VSR1 Reference Stall Speed in a Specific Configuration

Advisory Circular Feedback If you find an error in this AC, have recommendations for improving it, or have suggestions for new items/subjects to be added, you may let us know by (1) emailing this form to 9-AWA-AVS- AIR500-Coord@faa.gov or (2) faxing it to the attention of the Aircraft Certification Service Directives Management Officer at (202) 267-3983.

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