Cessna 421C Corroded Oxygen Line While in process of checking the individual oxygen masks during an annual inspection and five-year O2 bottle re-certification, a technician heard a very faint sound of a gas leak in the overhead interior paneling of the aircraft. After pulling the headliner for a closer inspection and plumbing in low-pressure nitrogen for troubleshooting, the technician narrowed down the “hiss” to a line just forward of the cabin door (p/n 5100107-46). To access this line, which passes through a structural beam in the overhead, it 288
Just Plain Broken
While in process of checking the individual oxygen masks during an annual inspection and five-year O2 bottle re-certification, a technician heard a very faint sound of a gas leak in the overhead interior paneling of the aircraft. After pulling the headliner for a closer inspection and plumbing in low-pressure nitrogen for troubleshooting, the technician narrowed down the "hiss" to a line just forward of the cabin door (p/n 5100107-46). To access this line, which passes through a structural beam in the overhead, it was necessary to drill out approximately 40 rivets securing a thin honeycomb panel to the overhead (structure). Above the panel is the ducting supplying the cabin Wemac vents. The line as pictured has been cleaned up and the corrosion removed for clarity. The corrosion occurred where the ducting passed under it. The ducting was removed to facilitate line removal, and was found to be totally deteriorated.
Key Takeaways:
- A Cessna 421C was found to have a corroded oxygen line, caused by deteriorated adjacent ducting, discovered during an annual inspection.
- Piper PA28 aircraft are experiencing recurring issues with cracked flap handle support mount brackets, attributed to fatigue and air loads.
- A newly installed oil cooler on a Robinson R22-A helicopter cracked after only 16.8 hours, leading to oil loss and an emergency landing.
- New Superior Air Parts through-bolts for a Continental IO-520 C engine have repeatedly snapped shortly after final torque application.
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