FAR 23.2140 — Airplane Trim
FAR 23.2140 sets trim requirements for Part 23 airplanes — lateral, directional, and longitudinal trim in cruise, climb, descent, and approach.
In Plain English
FAR 23.2140 is a Part 23 airworthiness standard that defines how a certificated airplane must behave when trimmed. The rule ensures the pilot can fly hands-off in normal flight regimes without fighting the controls.
The regulation breaks trim requirements into three categories:
- Lateral and directional trim: The airplane must hold trim with no further pilot input on primary or trim controls. This applies to Level 1, 2, and 3 airplanes in cruise, and to Level 4 airplanes in normal operations.
- Longitudinal trim: The airplane must hold pitch trim hands-off during climb, level flight, descent, and approach.
- Residual control forces: Any leftover stick or rudder force must not fatigue or distract the pilot during normal operations, or during likely abnormal or emergency operations, including a critical engine failure on multiengine airplanes.
Why it matters operationally: a properly trimmed airplane reduces pilot workload, improves precision in approach and cruise, and ensures the airplane remains controllable when something goes wrong — like an engine failure on a twin.
Regulation Text
14 CFR § 23.2140§ 23.2140 Trim.
(a) The airplane must maintain lateral and directional trim without further force upon, or movement of, the primary flight controls or corresponding trim controls by the pilot, or the flight control system, under the following conditions:
(1) For levels 1, 2, and 3 airplanes in cruise.
(2) For level 4 airplanes in normal operations.
(b) The airplane must maintain longitudinal trim without further force upon, or movement of, the primary flight controls or corresponding trim controls by the pilot, or the flight control system, under the following conditions:
(1) Climb.
(2) Level flight.
(3) Descent.
(4) Approach.
(c) Residual control forces must not fatigue or distract the pilot during normal operations of the airplane and likely abnormal or emergency operations, including a critical loss of thrust on multiengine airplanes.
Oral Exam Questions a DPE Might Ask
Q1What trim conditions must a Part 23 airplane meet under FAR 23.2140?
Per FAR 23.2140, the airplane must maintain lateral and directional trim hands-off in cruise (Levels 1–3) or normal operations (Level 4), and longitudinal trim during climb, level flight, descent, and approach.
Q2Under FAR 23.2140, what is required of residual control forces during an engine failure on a multiengine airplane?
FAR 23.2140(c) requires that residual control forces not fatigue or distract the pilot during normal, abnormal, or emergency operations, including a critical loss of thrust on multiengine airplanes.
Q3Does FAR 23.2140 require the airplane to maintain longitudinal trim during approach?
Yes. FAR 23.2140(b) specifically requires the airplane to maintain longitudinal trim hands-off during climb, level flight, descent, and approach.
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