Piper Part Number / Spec - Military Standard MS29526-2 Aircraft Fuel Cap, Red

The MS29526-2 aircraft fuel cap is designed to lock, seal, and vent the pressure refuel port on an aircraft fuel tank. It enables safe single-point pressure refueling on larger aircraft while maintaining a secure seal during operation. By protecting the fuel system from contamination and pressure irregularities, it plays a critical role in maintaining fuel system integrity and operational safety.

Pressure refueling delivers fuel through a centralized port, improving efficiency and reducing service time. The MS29526-2 cap is engineered to operate within defined pressure ratings, including operating, proof, and burst limits. Its manual actuation design allows technicians to vent and unlock the cap safely before refueling and securely reseal it afterward.

The MS29526-2 fuel cap is designed in accordance with the MIL-C-8605B technical requirements and the MS29526-2 envelope requirements. It also references compliance with RR-C-271 for anti-sparking lanyards and MS24484 for pressure refuel adapter compatibility. These standards ensure the cap meets rigorous aviation performance and safety criteria.

The fluorosilicone O-ring seal provides chemical resistance and maintains sealing performance across wide temperature ranges. This is essential for compatibility with all approved aircraft fuels and for preventing leaks under varying pressure conditions. A reliable seal reduces the risk of fuel vapor escape and environmental contamination.

The MS29526-2 cap includes an anti-sparking lanyard to prevent ignition risks during fueling. The lanyard keeps the cap attached to the aircraft, reducing the risk of foreign object debris (FOD) or misplaced hardware on the ramp. This design feature supports both safety compliance and operational efficiency.

The cap is engineered for use across broad temperature ranges, including extreme cold and elevated ambient conditions. It is built to withstand mechanical stresses, including pull tests and torque limits defined by the specification. These characteristics ensure dependable performance in diverse operating environments.

Aircraft fuel caps play a vital role in minimizing ignition sources during fueling operations. The MS29526-2 cap incorporates materials and design features that reduce the potential for sparking.

The MS29526-2 cap is commonly used on aircraft equipped with pressure refueling systems designed for single-point fueling. It mates with adapters built to military specifications, ensuring proper fit and sealing performance. This makes it suitable for many commercial, military, and special-mission aircraft platforms.

Correct installation torque ensures that the fuel cap seals properly without damaging threads or sealing surfaces. Undertightening can lead to leaks, while overtightening may cause component wear or distortion. Adhering to specification torque limits helps maintain system reliability and airworthiness compliance.