FAR 23.2430 — Fuel System Requirements
FAR 23.2430 sets fuel system design rules for Part 23 airplanes: independence, lightning protection, contamination prevention, jettison, and crash safety.
In Plain English
FAR 23.2430 establishes the airworthiness design standards for fuel systems on Part 23 (small) airplanes. It tells manufacturers how the fuel system must be built so pilots can rely on it in all phases of flight.
Every fuel system must:
- Keep multiple fuel storage and supply systems independent, so one failure doesn't drain or disable another.
- Prevent ignition from lightning strikes, corona, or streamering at vent outlets.
- Deliver fuel to each powerplant and APU under all likely operating conditions.
- Give the flightcrew a way to know total usable fuel and supply it without interruption.
- Allow fuel to be safely removed or isolated from the airplane.
- Retain fuel during a survivable emergency landing to protect occupants.
- Prevent hazardous contamination of fuel reaching the engines.
Fuel storage systems must withstand operating loads, be isolated from personnel compartments, prevent vent losses, supply at least 30 minutes at maximum continuous power, and be capable of safe jettison if needed. Refilling/recharging systems must prevent misfueling, contamination, and hazards to people or the airplane.
This matters operationally because it's why your fuel gauges, vents, sumps, and selectors work the way they do — and why preflight fuel checks are required.
Regulation Text
14 CFR § 23.2430§ 23.2430 Fuel systems.
(a) Each fuel system must—
(1) Be designed and arranged to provide independence between multiple fuel storage and supply systems so that failure of any one component in one system will not result in loss of fuel storage or supply of another system;
(2) Be designed and arranged to prevent ignition of the fuel within the system by direct lightning strikes or swept lightning strokes to areas where such occurrences are highly probable, or by corona or streamering at fuel vent outlets;
(3) Provide the fuel necessary to ensure each powerplant and auxiliary power unit functions properly in all likely operating conditions;
(4) Provide the flightcrew with a means to determine the total useable fuel available and provide uninterrupted supply of that fuel when the system is correctly operated, accounting for likely fuel fluctuations;
(5) Provide a means to safely remove or isolate the fuel stored in the system from the airplane;
(6) Be designed to retain fuel under all likely operating conditions and minimize hazards to the occupants during any survivable emergency landing. For level 4 airplanes, failure due to overload of the landing system must be taken into account; and
(7) Prevent hazardous contamination of the fuel supplied to each powerplant and auxiliary power unit.
(b) Each fuel storage system must—
(1) Withstand the loads under likely operating conditions without failure;
(2) Be isolated from personnel compartments and protected from hazards due to unintended temperature influences;
(3) Be designed to prevent significant loss of stored fuel from any vent system due to fuel transfer between fuel storage or supply systems, or under likely operating conditions;
(4) Provide fuel for at least one-half hour of operation at maximum continuous power or thrust; and
(5) Be capable of jettisoning fuel safely if required for landing.
(c) Each fuel storage refilling or recharging system must be designed to—
(1) Prevent improper refilling or recharging;
(2) Prevent contamination of the fuel stored during likely operating conditions; and
(3) Prevent the occurrence of any hazard to the airplane or to persons during refilling or recharging.
Oral Exam Questions a DPE Might Ask
Q1What does FAR 23.2430 require regarding the independence of fuel systems on a multi-tank airplane?
Per FAR 23.2430(a)(1), the fuel system must be arranged so that failure of any one component in one system will not cause loss of fuel storage or supply in another system.
Q2How much fuel must a Part 23 fuel storage system be capable of supplying at minimum?
FAR 23.2430(b)(4) requires the fuel storage system to provide fuel for at least one-half hour of operation at maximum continuous power or thrust.
Q3What protections does FAR 23.2430 require against fuel ignition and contamination?
FAR 23.2430(a)(2) requires the system to prevent ignition from direct or swept lightning strikes and from corona or streamering at vent outlets, and (a)(7) requires preventing hazardous contamination of fuel supplied to each powerplant and APU.
Studying for a checkride?
Related Sections in Part 23