# AA.I.D — High-Altitude Aerodynamics (ATP) (AMEL, AMES) — Airline Transport Pilot Airplane ACS

> AA.I.D from FAA-S-ACS-11A, including the official objective, references, notes, and 14 exact knowledge, risk-management, and skill descriptions.

Canonical HTML: [https://www.check-ride.ai/acs/airplane/airline-transport-pilot/aa-i-d](https://www.check-ride.ai/acs/airplane/airline-transport-pilot/aa-i-d)

Site reference: [https://www.check-ride.ai/llms.txt](https://www.check-ride.ai/llms.txt)

## Official Task context

- FAA document: Airline Transport Pilot and Type Rating for Airplane Category Airman Certification Standards
- Identifier: FAA-S-ACS-11A
- Published source date: November 2023
- Aircraft category: Airplane
- Certificate or rating: Airline Transport Pilot
- Area of Operation: Area of Operation I. Preflight Preparation
- Task: Task D. High-Altitude Aerodynamics (ATP) (AMEL, AMES)
- Task code prefix: AA.I.D
- Official references: AC 61-107, AC 61-138, AC 120-111; FAA-H-8083-2, FAA-H-8083-3, FAA-H-8083-25
- FAA source library: https://www.faa.gov/training_testing/testing/acs

## Official Task objective

To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with
high altitude airplane aerodynamics.

## Knowledge elements

- **AA.I.D.K1** — Aerodynamics of large transport category airplanes, including flight characteristics of swept wing
airplanes (e.g., Mach buffet).
- **AA.I.D.K2** — Energy management.
- **AA.I.D.K3** — Relationship between Mach number, indicated airspeed, true airspeed, and change over altitudes.
- **AA.I.D.K4** — Load factor at high altitude and its effect on high and low speed operating margins.
- **AA.I.D.K5** — Relationship between altitude capability, weight, and temperature.
- **AA.I.D.K6** — Maximum Operating Speed - Knots (VMO) / Maximum Operating Speed - Mach (MMO) convergence and
stall angle of attack.
- **AA.I.D.K7** — Maximum Lift over Drag Ratio (L/DMAX).
- **AA.I.D.K8** — Best range and best endurance.
- **AA.I.D.K9** — Factors which contribute to airplane upsets at high altitude and upset prevention and recovery
techniques.

## Risk management elements

- **AA.I.D.R1** — Managing the airplane’s energy state.
- **AA.I.D.R2** — High operating altitudes at high operational weights.
- **AA.I.D.R3** — High altitude slow-downs and excursions behind the power curve.
- **AA.I.D.R4** — Turbulence at high altitude.

## Skills elements

- **AA.I.D.S1** — If a cruise altitude is reached, manage the airplane’s systems and energy state.

## Difficulty methodology

Difficulty calibration is ongoing for this Task. Observed difficulty is a privacy-thresholded check-ride.ai mock-oral practice proxy, not an FAA practical-test pass or fail rate. Underlying sample sizes and the private reporting threshold are not published.

## Official Task notes

- Note: See Appendix 1: Practical Test Roles, Responsibilities, and Outcomes and Appendix 3: Aircraft,
Equipment, and Operational Requirements & Limitations for information related to this Task.

## Use in practice

A mock examiner can ask a pilot to explain the published elements, apply them to the configured aircraft and airport context, identify risks, and defend a decision. Practice prompts are not represented as actual FAA examiner scripts or predictions of the questions a candidate will receive.