Air Plains Services Gains PMA for Airbox Filter Seal Assembly for 172L/M Models

WELLINGTON, KS (July 31, 2025) – Air Plains Services, a world leader in general aviation engine and avionics upgrades, announced today it has gained Parts Manufacturing Approval from the Federal Aviation Administration for the airbox filter seal assembly for Cessna 172 L and M model aircraft.

“The seal assembly is an important part of the cooling system and plays a key role in proper CHT management,” said Katie Church, president of Air Plains. “We specialize in PMA parts for Cessna piston, particularly the cooling system, and when we find ways to improve on an original design, we want to add it our product range.”

Mechanics at Air Plains report the absence of the filter seal assembly on many L and M model Cessna 172 Skyhawks coming in for engine upgrades. This can cause a change in designed air flow over the engine, resulting in higher CHTs, as much as 10 to 15 degrees F.

“The seal is essential to achieve a greater pressure differential in the engine compartment that strengthens the flow of cooler air over the engine,” Church said. “As we’ve done with other components such as the airbox, we’ve made it better, easy to install and less expensive than other options.”

Air Plains opted for a special, lightweight polycarbonate plastic due to its higher temperature resistance, weight and strength. The fiberglass-reinforced silicone material is a single piece seal that provides the best differential pressure between the upper and lower cowl and is designed for easy installation.

Air Plains offers a wide range of PMA parts for the induction system including airboxes, collars, gaskets, adjustable brackets and baffles assemblies, all available at the company’s online store.

For information about the new airbox filter seal assembly or any Air Plains product, call 1-800-752-8481 or +1-620-326-8904 or send an email to sales@airplains.com.

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Air Plains Services, based in Wellington, Kansas, is a leader in general aviation aircraft upgrades, specializing in high performance engine upgrades for most Cessna 172, 180 and 182/182RG piston aircraft, avionics systems and components as well as custom avionics panels, high quality spare parts and enhanced performance systems, and aircraft modification and maintenance. Air Plains stands apart from most other companies, shipping complete, ready-to-install engine upgrade kits anywhere in the world. Air Plains Services, serving the aerospace industry for more than 40 years, is also the home of the Inpulse ADI modification that allows high compression aircraft engines to use 91 octane auto fuel. Air Plains also owns Petersen Aviation of Minden, Nebraska, known worldwide for its wide inventory of Supplemental Type Certificates (STCs) that allow general aviation aircraft owners to use less expensive, unleaded auto fuel instead of 100LL avgas.

 For more information, visit the Air Plains website at www.airplains.com and follow the company on the Air Plains Facebook and Instagram pages. For information on Air Plains’ Inpulse system for unleaded auto fuel, visit www.flyinpulse.com.