14 CFR § 25.405 - Secondary control system.

---
identifier: "/us/cfr/t14/s25.405"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "14 CFR § 25.405 - Secondary control system."
title_number: 14
title_name: "Aeronautics and Space"
section_number: "25.405"
section_name: "Secondary control system."
chapter_name: "FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "C"
subchapter_name: "AIRCRAFT"
part_number: "25"
part_name: "AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "49 U.S.C. 106(f), 106(g), 40113, 44701, 44702 and 44704; Pub. L. 115-254, 132 Stat 3281 (49 U.S.C. 44903 note)."
regulatory_source: "Docket No. 5066, 29 FR 18291, Dec. 24, 1964, unless otherwise noted."
cfr_part: "25"
---


# 25.405 Secondary control system.

Secondary controls, such as wheel brake, spoiler, and tab controls, must be designed for the maximum forces that a pilot is likely to apply to those controls. The following values may be used:

Pilot Control Force Limits (Secondary Controls)

| Control | Limit pilot forces |
| --- | --- |
| Miscellaneous: |  |
| *Crank, wheel, or lever | ((1 + R) / 3) × 50 lbs., but not less than 50 lbs. nor more than 150 lbs. (R = radius). (Applicable to any angle within 20° of plane of control). |
| Twist | 133 in.-lbs. |
| Push-pull | To be chosen by applicant. |
| *Limited to flap, tab, stabilizer, spoiler, and landing gear operation controls. |  |