FAR 23.2225 — Component Loading Conditions
FAR 23.2225 explains the structural design loads applicants must determine for engine mounts, flight controls, high-lift surfaces, and pressurized cabins.
In Plain English
FAR 23.2225 is a Part 23 airworthiness standard that tells designers of small airplanes which structural design loads they must account for on key components. While you won't be operating to this rule day-to-day, knowing it helps you understand why your airplane's limits exist.
The applicant must determine loads acting on:
- Engine mounts and supporting structure — must handle powerplant operation combined with flight gust and maneuver loads, plus sudden powerplant stoppage for non-reciprocating (turbine) engines.
- Flight controls, high-lift surfaces, and their systems — designed for surface inertia and mass balance, gusts and maneuvers, pilot or automated inputs, system issues like jamming and friction, and taxi, takeoff, and landing loads (including downwind taxi and surface gusts).
- Pressurized cabins — must withstand pressurization differential from zero up to maximum relief pressure combined with gust/maneuver loads; combined with ground/water loads if the airplane may land pressurized; and at 1.33 × maximum relief pressure alone.
Operationally, this is why the manufacturer publishes maneuvering speeds, control limits, and pressurization schedules — exceeding them can exceed what the structure was certified to handle.
Regulation Text
14 CFR § 23.2225§ 23.2225 Component loading conditions.
The applicant must determine the structural design loads acting on:
(a) Each engine mount and its supporting structure such that both are designed to withstand loads resulting from—
(1) Powerplant operation combined with flight gust and maneuver loads; and
(2) For non-reciprocating powerplants, sudden powerplant stoppage.
(b) Each flight control and high-lift surface, their associated system and supporting structure resulting from—
(1) The inertia of each surface and mass balance attachment;
(2) Flight gusts and maneuvers;
(3) Pilot or automated system inputs;
(4) System induced conditions, including jamming and friction; and
(5) Taxi, takeoff, and landing operations on the applicable surface, including downwind taxi and gusts occurring on the applicable surface.
(c) A pressurized cabin resulting from the pressurization differential—
(1) From zero up to the maximum relief pressure combined with gust and maneuver loads;
(2) From zero up to the maximum relief pressure combined with ground and water loads if the airplane may land with the cabin pressurized; and
(3) At the maximum relief pressure multiplied by 1.33, omitting all other loads.
Oral Exam Questions a DPE Might Ask
Q1What loads must an engine mount on a Part 23 airplane be designed to withstand?
Per FAR 23.2225(a), the engine mount and its supporting structure must withstand loads from powerplant operation combined with flight gust and maneuver loads, and for non-reciprocating powerplants, sudden powerplant stoppage.
Q2Under FAR 23.2225, what kinds of conditions must flight controls and high-lift surfaces be designed for?
FAR 23.2225(b) requires designing for surface inertia and mass balance, flight gusts and maneuvers, pilot or automated inputs, system-induced conditions like jamming and friction, and taxi, takeoff, and landing loads including downwind taxi and surface gusts.
Q3How does FAR 23.2225 address structural loads on a pressurized cabin?
FAR 23.2225(c) requires the cabin to handle pressurization differential from zero up to maximum relief pressure combined with gust and maneuver loads, combined with ground/water loads if it may land pressurized, and at 1.33 times maximum relief pressure with no other loads.
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Related Sections in Part 23