Wake Turbulence Basics

AIM ¶ 7-4-1 — Wake Turbulence Basics

AIM 7-4-1 explains wake turbulence basics: counter-rotating vortices, rolling moments, and pilot awareness. Study guide for written, oral, and checkride prep.

In Plain English

Per AIM 7-4-1, every aircraft in flight generates wake turbulence as a byproduct of producing lift. This wake takes the form of two counter-rotating vortices that trail behind the wingtips of the generating aircraft.

Why it matters to you as a pilot:

The danger to a following aircraft depends on the strength, duration, and direction of the vortices.
A wake encounter can produce rolling moments that exceed your roll-control authority — meaning full aileron may not be enough to recover.
Consequences can include injury to occupants and structural damage to the aircraft.

The AIM's guidance is simple but critical: always anticipate the possibility of flying through another aircraft's wake — especially behind larger, heavier, slower, and clean-configuration aircraft — and adjust your flight path to avoid it. This is recommended practice in the AIM, but avoidance techniques tie directly into ATC separation standards and pilot-in-command responsibility under the FARs. Awareness is your first line of defense; later sections of AIM Chapter 7-4 cover specific avoidance procedures.

AIM Source Text

FAA AIM ¶ 7-4-1

7-4-1. 7-4-1. General Every aircraft generates wake turbulence while in flight. Wake turbulence is a function of an aircraft producing lift, resulting in the formation of two counter-rotating vortices trailing behind the aircraft. Wake turbulence from the generating aircraft can affect encountering aircraft due to the strength, duration, and direction of the vortices. Wake turbulence can impose rolling moments exceeding the roll-control authority of encountering aircraft, causing possible injury to occupants and damage to aircraft. Pilots should always be aware of the possibility of a wake turbulence encounter when flying through the wake of another aircraft, and adjust the flight path accordingly.

Oral Exam Questions a DPE Might Ask

Q1What causes wake turbulence, and what form does it take behind an aircraft?

Per AIM 7-4-1, wake turbulence is a function of an aircraft producing lift. It forms as two counter-rotating vortices trailing behind the aircraft. Every aircraft in flight generates this wake.

Q2Why is a wake turbulence encounter potentially dangerous to a following aircraft?

Per AIM 7-4-1, wake turbulence can impose rolling moments that exceed the roll-control authority of the encountering aircraft, possibly causing injury to occupants and damage to the aircraft. The hazard depends on the strength, duration, and direction of the vortices.

Q3What does the AIM recommend pilots do regarding wake turbulence?

Per AIM 7-4-1, pilots should always be aware of the possibility of a wake turbulence encounter when flying through the wake of another aircraft and adjust their flight path accordingly to avoid it.

Related Paragraphs in AIM Chapter 7

¶ 7-4-2

Wake Vortex Generation

Wake Turbulence Problem Areas

¶ 7-4-6

Wake Turbulence Avoidance

¶ 7-4-7