For sale is one complete kit of high quality fluorosilicone o-rings for Shaw 416 type fuel caps found on many Beechcraft, Cessna, Piper, and Mooney aircraft. Each kit equips one fuel cap and includes the following items: M25988/1-232 3.0" o-ring, M25988/1-010 small o-ring, and an MS24665-132 cotter pin for the bottom of the fuel cap. This kit replaces the following Buna-N (nitrile) o-rings: MS29513-232 and MS25988-010.
These fluorosilicone o-rings offer superior durability to help your fuel caps keep fuel in and to keep water out. By not inspecting and replacing worn o-rings, worn rings are a source for fuel contamination as water leaks into fuel tanks.
Kits provide standard aircraft parts acceptable under 14 CFR §21.9 for a FAA certificated mechanic to install two military specification fluorosilicone type o-rings on Shaw 531,457, 431,416, or Gabb style fuel caps. Kits are eligible for installation by a licensed mechanic as a minor alteration under 14 CFR §1.1 and §21.93(a) as it has “no appreciable effect on the weight, balance, structural strength, reliability, operational characteristics, or other characteristics affecting the airworthiness” of the aircraft. No STC, Form 337 submittal or FSDO field approval is required per FAA Order 8900.1 Figure 4-67. A §43.9 airframe logbook entry is sufficient to document this alteration and return the aircraft to service. Also includes an aviation grade cotter pin.” Fluorosilicone are a much more durable material and will last longer than original Buna-N (Nitrile) rings found in Shaw and Gabb fuel caps. Fluorosilicone can withstand a broader range (-100 to 350 degree Fahrenheit) whereas Buna-N has a lower temperature range (-70 to 180 degree Fahrenheit). The manufacturers of the fluorosilicone o-rings are ISO17025 certified. Fuel caps should be inspected for continued airworthiness per your respective aircraft repair manual.