PERFORMANCE

Airspeed, groundspeed & wind

FLIGHT SCIENCE / CONCEPT REFERENCE

SCIENCEConditions & principles

Airspeed describes motion through air; groundspeed describes motion relative to Earth.

REFERENCE COVERAGE3 / 3 editorial sections

PROVENANCE1 linked source

LAST RETRIEVED2026-09-05

Editorial section coverage describes the article structure, not scientific validation or completeness.

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Source editions

PHAK · Chapter 11: Aircraft Performance ↗Edition / snapshot: FAA-H-8083-25C, 2023Retrieved: 2026-09-05

Retrieval dates record when Owl obtained the data; they are not publication dates or proof that a specification is current. Where the edition contains only a snapshot date, the original publication date is not recorded.

Mechanism

The velocity of an aircraft relative to the ground is the vector sum of its air-relative velocity and wind velocity.

Aircraft response

A headwind lowers along-track groundspeed for a given airspeed. Changes in atmospheric density alter the relationship between indicated and true airspeed.

Context & interpretation

IAS, CAS, EAS and TAS include different corrections. Wind does not directly change the airspeed required to produce a given aerodynamic force in steady uniform flow.

Physical relationship

Vground = Vair + Vwind

Vector sum; direction matters, especially with crosswind.

Sources & context

PHAK · Chapter 11: Aircraft Performance

FAA · Retrieved 2026-09-05

Educational reference; original Owl summaries

Educational explanation of physical mechanisms. Aircraft-specific procedures, limitations and current weather information are separate references.