# AI.II.N — High Altitude Operations - Supplemental Oxygen — Flight Instructor Airplane ACS

> AI.II.N from FAA-S-ACS-25, including the official objective, references, notes, and 16 exact knowledge, risk-management, and skill descriptions.

Canonical HTML: [https://www.check-ride.ai/acs/airplane/flight-instructor/ai-ii-n](https://www.check-ride.ai/acs/airplane/flight-instructor/ai-ii-n)

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

## Official Task context

- FAA document: Flight Instructor for Airplane Category Airman Certification Standards
- Identifier: FAA-S-ACS-25
- Published source date: November 2023
- Aircraft category: Airplane
- Certificate or rating: Flight Instructor
- Area of Operation: Area of Operation II. Technical Subject Areas
- Task: Task N. High Altitude Operations - Supplemental Oxygen
- Task code prefix: AI.II.N
- Official references: 14 CFR part 91; AC 61-107; AIM; FAA-H-8083-2, FAA-H-8083-3, FAA-H-8083-9, FAA-H-8083-25; POH/AFM
- 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 flight at higher altitudes where supplemental oxygen is required or recommended, can apply that knowledge, manage associated risks, demonstrate appropriate skills, and provide effective instruction.

## Knowledge elements

- **AI.II.N.K1** — Regulatory requirements for supplemental oxygen use by flight crew and passengers.
- **AI.II.N.K2** — Physiological factors, including:
- **AI.II.N.K2a** — Impairment
- **AI.II.N.K2b** — Symptoms of hypoxia
- **AI.II.N.K2c** — Time of useful consciousness (TUC)
- **AI.II.N.K3** — Operational factors, including:
- **AI.II.N.K3a** — Characteristics, limitations, and applicability of continuous flow, demand, and pressure-demand oxygen systems
- **AI.II.N.K3b** — Differences between and identification of “aviator’s breathing oxygen” and other types of oxygen
- **AI.II.N.K3c** — Precautions when using supplemental oxygen systems

## Risk management elements

- **AI.II.N.R1** — High altitude flight.
- **AI.II.N.R2** — Use of supplemental oxygen.
- **AI.II.N.R3** — Management of compressed gas containers.
- **AI.II.N.R4** — Combustion hazards in an oxygen-rich environment.

## Skills elements

- **AI.II.N.S1** — Provide an adequate briefing on use of supplemental oxygen equipment.
- **AI.II.N.S2** — Operate or simulate operation of the installed or portable oxygen equipment in the aircraft, if installed or available.
- **AI.II.N.S3** — Determine the quantity of supplemental oxygen required in a scenario given by the evaluator.

## 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.

## 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.