FAR 23.2120 — Climb Performance Requirements
FAR 23.2120 sets minimum climb gradients for Part 23 airplanes: all-engines, engine-out, and balked landing. Key certification standards explained.
In Plain English
FAR 23.2120 establishes the minimum climb performance that Part 23 airplanes must demonstrate out of ground effect during certification. While this is a design/certification rule (not an operating rule), understanding it helps you appreciate why your POH climb numbers exist and why they must be respected.
The rule covers three scenarios:
- All engines operating, initial climb: Levels 1 and 2 low-speed airplanes must achieve 8.3% gradient (landplanes) or 6.7% (seaplanes/amphibians). Level 1 and 2 high-speed, all level 3, and level 4 single-engines must achieve 4% after takeoff.
- Critical engine loss on multiengine airplanes: Required gradients range from 1% to 2% at 400 ft AGL depending on airplane level and configuration; certain low-speed twins must show 1.5% at 5,000 ft pressure altitude in cruise configuration.
- Balked landing: A 3% climb gradient with gear down and flaps in the landing configuration, achievable without undue pilot workload.
Operationally, this is why published climb gradients in your AFM are dependable — and why losing an engine in a light twin leaves very little margin.
Regulation Text
14 CFR § 23.2120§ 23.2120 Climb requirements.
The design must comply with the following minimum climb performance out of ground effect:
(a) With all engines operating and in the initial climb configuration(s)—
(1) For levels 1 and 2 low-speed airplanes, a climb gradient of 8.3 percent for landplanes and 6.7 percent for seaplanes and amphibians; and
(2) For levels 1 and 2 high-speed airplanes, all level 3 airplanes, and level 4 single-engines a climb gradient after takeoff of 4 percent.
(b) After a critical loss of thrust on multiengine airplanes—
(1) For levels 1 and 2 low-speed airplanes that do not meet single-engine crashworthiness requirements, a climb gradient of 1.5 percent at a pressure altitude of 5,000 feet (1,524 meters) in the cruise configuration(s);
(2) For levels 1 and 2 high-speed airplanes, and level 3 low-speed airplanes, a 1 percent climb gradient at 400 feet (122 meters) above the takeoff surface with the landing gear retracted and flaps in the takeoff configuration(s); and
(3) For level 3 high-speed airplanes and all level 4 airplanes, a 2 percent climb gradient at 400 feet (122 meters) above the takeoff surface with the landing gear retracted and flaps in the approach configuration(s).
(c) For a balked landing, a climb gradient of 3 percent without creating undue pilot workload with the landing gear extended and flaps in the landing configuration(s).
[Doc. No. FAA-2015-1621, Amdt. 23-64, 81 FR 96689, Dec. 30, 2016, as amended by Doc. No. FAA-2022-1355, Amdt. 23-65, 87 FR 75710, Dec. 9, 2022]
Oral Exam Questions a DPE Might Ask
Q1What climb gradient must a Part 23 airplane demonstrate during a balked landing?
Per FAR 23.2120(c), the airplane must achieve a 3 percent climb gradient with the landing gear extended and flaps in the landing configuration, without creating undue pilot workload.
Q2After a critical loss of thrust on a level 4 multiengine airplane, what climb gradient is required and at what altitude?
FAR 23.2120(b)(3) requires a 2 percent climb gradient at 400 feet above the takeoff surface, with the landing gear retracted and flaps in the approach configuration.
Q3What all-engines-operating climb gradient is required for a level 2 low-speed landplane in the initial climb configuration?
Under FAR 23.2120(a)(1), the airplane must demonstrate an 8.3 percent climb gradient out of ground effect (6.7 percent if it is a seaplane or amphibian).
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Related Sections in Part 23