Our Aging Aircraft
Staying ahead of the curve by Jeff
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:
- Hoses If your hoses are more than 5 years
old, replace them. Hoses are probably the most commonly
neglected maintenance item.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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
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!