Shelf life: What Does it
By H. Dean Chamberlain
Reprinted with permission from
FAA Aviation News
A lesson about shelf life'or how I
learned to buy two new turn coordinators. As a relatively new aircraft
owner, I have learned many expensive lessons. Most of those lessons
were discussed in my previous hopefully humorous attempts at
explaining the joys of being a new owner of an old aircraft. I would
like to add a postscript to my last article on the subject.
The week before Thanksgiving, I had
the 'pleasure' of buying a second new turn coordinator (TC) from
Mid-Continent Instruments in Wichita Kansas. The first unit was dead
on installation (DOI), which should not be confused with dead on
arrival or DOA. As I explained in my other articles on the upgrading
of my old Piper
Tripacer, the project took much longer, years
longer, then expected. The project included the replacement of all of
the flight, navigation, and engine instrumentation.
Buying a new instrument is not the
same as having a new instrument. When I ordered all of the new
instruments from various suppliers, the last thing I thought about was
the term 'shelf life.' However, shelf life can be critical when
working with aircraft. Basically, shelf life is how long an item can
be shelved or stored while remaining usable. In the case of my DOI TC,
I dutifully boxed it up a few weeks ago and sent it back to the
factory after having exchanged emails with a company representative.
When I never received any word about the TC, I called the company and
talked with a customer service representative. A day later, I was
contacted with the post mortem report. The TC was dead. The apparent
cause was the expiration of its shelf life. According to the woman who
called me, the bushings had died and some other items were not
Although never used, the unit failed
to operate on its first flight. The woman I spoke with said it had
been manufactured years earlier and was out of warranty. The unit had
'died' in its shipping box.
She offered to repair the unit with
the exception of correcting a small, visual defect, for about $190.
The blemish would cost more she said. The repaired unit would come
with a 90-day warranty. In discussing my options with her, I chose to
buy a new unit for almost $500. The reason I chose to buy another new
unit was its one-year warranty. If this unit failed, I wanted some
When I purchased my TC and all of the
other items, I really didn't think about warranties and limited shelf
life. But then, I didn't think my upgrade project would stretch out
over three and a half years. So, when I was buying items for the
aircraft, I had no idea that all of the warranties would expire before
the items were installed.
The result, in the case of my DOI TC,
was the cost of buying another new unit. It was an expensive lesson.
Now, I pay attention to manufacturing, shelf life, and warranty dates.
A lesson I have learned. Three days
before I bought my second new TC, I bought new tires for my sport
utility vehicle. Having remembered a recent network news story about
recommended tire life dates, one of the first questions I asked the
dealer installing the tires was when were the tires manufactured. I
wanted 'new' tires, not unused tires made several years ago.
The folks at Mid-Continent were
pleasant and very helpful to work with. It was not the company's fault
my first TC was not installed upon receipt. It was my fault for not
thinking about why some items come with a shelf-life date. The date is
there for a reason. Just like bread has a sell by date to ensure its
freshness, so do some aircraft products. My problem was the
uncertainty and delay that comes with a part-time major upgrade
If your aircraft goes into the shop
for work, warranty dates should be no problem. But if your aircraft is
a 'basket case' or is a kit project or undergoing a major upgrade,
then your completion date may be unknown.
In such a case, my recommendation is
to avoid buying date limited items until the absolute last minute. In
my case, I would not have bought my limited warranty instruments that
were out of warranty before installation or my now two-generation old
IFR GPS until the day before the plane was ready to fly. If I had
waited until last June when the aircraft finally flew, my instruments
would still be in warranty, and I would have a different GPS in the
All of my efforts to save on buying my
instruments and GPS when I had the money and for what I thought were
good sale prices turned out to be very costly mistakes. In hindsight,
it would have been cheaper to have saved the money and bought the
instruments just before needed for installation.
As I have written before, please learn
from my mistakes and save yourself some money. So read and understand
all warranties before you buy and buy just before flight. The time,
money, and warranties you save will add to your project's enjoyment.