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Our Aging Aircraft – Part I:
Staying ahead of the curve by Jeff Simon

The recent tragedies in New York, Washington and Pennsylvania touched many of us very closely. The experience is a harsh reminder of how fleeting life can be and how important it is that we cherish it, and take care to protect it.

As pilots and aircraft owners, we make many decisions about how we approach our own flight safety. Many articles have been written about piloting safely, but few address the way that we approach the safety of the aircraft. Anyone who has been to one of my presentations knows that my favorite part of the FARs is: "The pilot-in-command of a civil aircraft is responsible for determining whether that aircraft is in a condition for safe flight". This means that it is our responsibility, not our mechanic's, to keep our aircraft in airworthy condition at all times.

Improper maintenance can occur at either end of the cost spectrum. The classic example is of the owner who knowingly cuts corners on maintenance and proper inspection procedures to save money. But another example is of the owner who knows little about the aircraft, uses the most expensive and reputable shop available, and assumes no responsibility for the aircraft's maintenance. Either case is a recipe for trouble.

The best safeguard against mechanical failure is knowledge, inspection and preventative maintenance. Many owners view maintenance as an annual ritual, assuming that nothing goes seriously wrong between annual inspections. Nothing could be further from the truth. Throughout the year, it is our job to ensure that the aircraft remains airworthy. This includes things such as routine inspection, lubrication, AD compliance, transponder and IFR certification and ELT battery expiration. But, it is also our job to proactively maintain the aircraft over the long haul.

The majority of our aircraft are getting quite old, and while only the wings, spar and engine are 'life limited', there are many components that should be replaced or refurbished proactively, due to their age. When I review reports of mechanical failure, some common areas stand out:

  1. Hoses – If your hoses are more than 5 years old, replace them. Hoses are probably the most commonly neglected maintenance item.
  2. Oil Analysis/Filter Inspection If you are not currently performing oil analysis at each oil change, I recommend that you start. It is an excellent way to learn more about the health of your engine.
  3. Valve Guides Our engines are particularly susceptible to early exhaust valve failure due to problems with the Valve/Valve Guide clearance. You may have heard of the "wobble check" to inspect for this problem. All Lycoming 0-320 and 0-360 engines should be inspected every 500hrs. More frequently doesn't hurt either! Talk to your mechanic to learn more.
  4. Brake Lines – There are many reports of brake failure due to corrosion wear and fatigue of the rigid brake lines on our aircraft. Inspect them carefully. If they are original, have them replaced.
  5. Alternator Belt – Most cars have specified intervals for belt replacement, regardless of condition. Taking the same approach with your plane will help reduce the risk of an electrical failure.
  6. Control Cables At our most recent convention, we learned first hand that control cables can fail if not carefully maintained and inspected on a regular basis. I recently had a discussion with the president of a major aircraft cable manufacturer on the topic of corrosion and fatigue. He had serious concerns about aircraft flying around with 25 year old cables.
  7. Throttle/Mixture/Carb Heat Cables These should all be carefully inspected. If any of your engine controls are stiff, they should be repaired or replaced.
  8. Vacuum Pump If you fly IFR, I strongly recommend that you replace your vacuum pump well before it's scheduled overhaul time. Vacuum pumps are not the most reliable component in the aircraft, and often fail without prior symptoms. The best protection, of course, is a backup system.

These are only a few of the many things that we can do to increase the safety of our aircraft. The key to excellent maintenance is education. I strongly recommend that all owners get their own copy of the parts and maintenance manual for their aircraft. Reviewing these publications can be an excellent starting point to learn how our planes are put together. I also recommend that anyone unfamiliar with the mechanical details of the aircraft schedule some time with their mechanic for a 'maintenance checkout'. A typical flying checkout teaches pilots about the proper operation of a new aircraft. A 'maintenance checkout' can teach you all about the systems, proper maintenance and routine inspection of the aircraft.

The FARs provide us with a baseline for keeping our aircraft airworthy by inspecting them on an annual basis. It's our responsibility, as owners and pilots, to take our maintenance to the next level so that our flying experience as safe and enjoyable as possible!


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