Anyone considering the purchase of a used
airplane should have a pre-purchase inspection completed. As airplanes trade owners and their age
increases, the need for a pre-purchase inspection is of far greater
importance. If you are purchasing a
virtually new airplane the process is of no less importance but should in
effect be shorter. However, most people
are purchasing older used airplanes. Many
40 year old planes are for sale and are still good buys.
Who should do it?
You should retain the services of a
professional, either an AME or a Maintenance shop, to do the inspection. Some shops prefer not to do these inspections
for fear of being blamed for missing something, but are willing to help you
after you have purchased the airplane.
If you can't trust each other before you buy how, will you trust each
other after?
What:
The pre-purchase inspection is to verify
the airworthiness and general condition of the airplane, its engine, propeller
and all installed systems and equipment for the prospective owner. The person you retain, whether an AME or
Maintenance shop, is working for YOU!
Some owners or prospective
owners choose to become involved, while others do not. In either case the work required is the same,
it's just a matter of who is doing it. Many savvy owners can be a wealth of
information on a particular airplane.
Ask your shop if you can be involved. An educated consumer is the best consumer.
Why:
In the past this inspection was a mere
formality, after all the fleet was young and airplanes were generally in good
condition. The AME would open the engine
cowlings, check the cylinder compression and possibly remove and examine the
oil filter for signs of engine troubles.
Following this was a basic walking inspection of the airplane, and a
brief review of the log books. This was
usually followed by a nod of approval.
Sometimes only a few hours were spent on
the entire process. Even today some people
believe that the process should only take a few hours, when in reality the
process could involve days of work depending on the complexity of the airplane. Times have changed. Airplanes are now
expensive investments, in some cases with values equal to or greater than one's
home. Over the years the inspection
process has become much more involved.
When:
Once you have narrowed down your search and
selected an airplane, you should obtain pictures of the interior, exterior and
instrument panel, followed by your personal inspection of the plane. There is no sense bringing your AME to the
airplane or airplane to him if you are not satisfied with the cosmetics of the
plane.
Where:
Although not always practical, the
inspection should take place in your AME's hangar. When working in his own shop the inspection quality
should be better: his own tools, manual, equipment, telephone and internet are
available as required. In many cases it
is more cost effective for you to pay the fuel expense of relocating the
airplane, than it is to relocate the AME.
In those cases where the distances are too great, you and your AME will
be traveling. Be prepared for airfare,
hotel, food and rental car expenses on top of the daily rate for the AME, as
well as possibly renting shop space and tools while away.
How:
Accident History:
Once satisfied with the cosmetics of the
airplane, the inspection process may begin.
First off is damage history. Lots of airplane advertisements list NDH (No
Damage History) or now the updated version NKDH (No Known Damage History). This is a handy catch phrase to let people off
the hook for damage that may be revealed during the inspection.
Several resources are available to help
with confirmation of this claim. If you
are purchasing an airplane from the USA you
can search the NTSB web site http://www.ntsb.gov/NTSB/Query.asp
using the registration marks to find any reported
accidents. This however is not a 100% guarantee.
The FAA knows a lot about most airplanes, but not everything about every
airplane is reported to them. The same holds true for Transport Canada. In Canada
you can search the CADORS web site http://www.tc.gc.ca/Aviation/applications/cadors/English/main.asp
to see if there are any reported
accidents or incidents involving the airplane. An accident history or damage history is not
always a reason to abandon the particular airplane; it is one of many factors
to consider. As the fleet ages, finding
that cream puff airplane is more challenging.
Sometimes just entering the airplane
registration marks into an internet search engine reveals interesting things
about an airplane.
Log Books and Technical History:
The vendor should be able provide the
serial number for the airframe, as well as make, model and serial numbers for
the engine and propeller as well as a list of all installed equipment, radios
etc. This information should now be
compared to the Type Certificate Data Sheets for this particular model
available at: http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/MainFrame?OpenFrameSet
Records of Airworthiness directive
compliance, service bulletins and letters, modifications completed by STC
(Supplemental Type Certificate) available at http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/MainFrame?OpenFrameSet
or "One time" approvals should be available. Note that "One time" foreign approvals are not
acceptable in Canada. Note that not all
maintenance shops have Service bulletins for all airframes. Some manufacturers have some of their
bulletins on line, Mooney for example has all of theirs on line available to
everyone.
Airworthiness directives are mandatory and
should be checked for compliance, both in the log books and by physical
inspection of the aircraft. In some
cases airworthiness directives are signed off as being complied with, when they
may not be. Some airworthiness
directives are very complex and can contain many parts.
When all these items check out, you can
move on to the log books or technical history for the airplane. Many owners now scan their logs to a computer
and can send them electronically. At
this point an interested purchaser, as well as the AME, should review the records. Hopefully the records begin when the plane
was new at the factory and continue through to present. Unfortunately this is not always the case. Many have missing records, early logs are not passed
on to new owners, maintenance shops lose them, and hangar fires have claimed
some. Some are "Lost" for other reasons
in attempts to hide un-favourable history.
In any case all available logs should be
read from cover to cover. Notes should
be made as to dates and times of repairs, modifications, Airworthiness
directive compliance, service bulletin and service letter compliance. Hour meter replacements should be noted to
help in calculating the real total time on the airplane.
While carrying out the review, look for
patterns of continuity. Did several
years go by with no recorded activity at all?
If so why? Was the engine
preserved during this time?
Note the dates and times for engine and
propeller overhaul, record these for calculating actual times on the components. This is useful information. I once carried out a pre-purchase on a Cessna
150 with very low total time, only to discover that the propeller had been
exchanged for one with almost 10,000 hours!
This propeller had not been to an overhaul shop for many years. The
likelihood of it failing at overhaul was quite high. In Canada, a
fixed pitch propeller requires a corrosion inspection every 5 years, while most
constant speed propellers require a 10 year overhaul.
When was the last pitot static, transponder
and altimeter system check completed? In
Canada and the USA it is required each 24 months.
What type of ELT is installed? Is
it approved in Canada? Is it 406 MHz? This item alone is quit costly and is
required in Canada with change of ownership.
Was the tachometer accuracy check completed? Tolerance is +/- 4%. Was the compass swung in the last year? Flight test:
With the review of the technical history
complete, you can move on to the flight test of the airplane and its systems. With the owner flying, have him or her
demonstrate all systems for correct function, making notes on faults as the
flight progresses. Do the radios work
correctly, both communication and navigation?
Ask to hand fly the plane yourself, does it fly wings level and ball
centred? Do the controls feel correct
and smooth? Engage the autopilot, does
it function in all modes? Is the engine
smooth or does it vibrate? Many have a
"Sweet spot" while others have restricted power ranges. Slow the airplane down and raise and lower
the landing gear, does the motor make unusual sounds? All systems should be functional other than
those revealed in the sales agreement.
Note any unusual odours in the cabin: fuel,
exhaust, dead mouse odour, etc. both on the ground and in the air. My hangar cat enjoys doing his own "Cat scan"
and has found mice and birds both dead and alive in more than one airplane!
Physical Inspection:
With the flight test completed and
satisfactory, the physical inspection can begin. Here, there is great debate as to the depth
of inspection required. Some prefer an
"Annual Inspection" check list. I use
the airframe manufacturer's inspection check list as well as one we have
developed in the shop. No matter what
method is used, thorough, very thorough
should be the requirement. Airplane
ownership has its share of surprises, the goal is to minimize them as much as
possible.
There is no correct starting point. I start with an examination of the data plates
and the serial numbers, these items should match those in the log books. There is no sense in continuing the
inspection if there is a discrepancy or a missing data plate.
I then move on to a walk around inspection
of the airplane making notes on the exterior of the airplane. A keen eye can spot many defects just on a
simple walk around. Next I move on to the
engine as it is one of the single most expensive systems in the airplane. Remove the cowls and carry out a cylinder
compression test while the engine is still hot, drain the oil and cut open the
oil filter or screen for examination. Using the check list as a guide, inspect
the engine and propeller and all of the sub-systems noting all defects as you
go.
With the engine inspected it is now time to
inspect the airframe. At this point I
turn on all of the systems to check for correct function, lights, stall vane,
pitot heat etc. Make notes on items which don't work.
Remove all
of the inspection covers and fairings for a thorough inspection. Look for signs of internal damage or
repair. Unusual rivet patterns or a
change in the type of rivet are signs of a repair, as are drill shavings left
in a wing. If these are found, do they
match the log books? Look for signs of
corrosion in the airframe as well. Make
notes as you proceed.
Inspect all of the flight control surfaces
for damage and correct travel. The Type
Certificate specifies the correct travel limits as does the maintenance
manual. Inspect the control systems for
worn or corroded cables, worn rod end bearings, etc.
Examine the windows for signs of cracks or
damage. Compare these to the manufacturer's maintenance manual. Chemical burns
from paint stripper are common, as are chips in pressurized windows.
Has the airplane been repainted? If so were the flight controls re-balanced
before installation? Was the aircraft
re-weighed with the painting? It is not
required but it is a good idea. Has the
interior fabric been replaced? Were the
materials approved? Is there
flammability certification for the material?
If it is a retractable landing gear
airplane, raise it up on jacks for a landing gear inspection. Is the gear worn and sloppy, cracked, rusting,
etc? Do the warning lights and position
lights function? How about the warning
horn and anti retraction system? Inspect
the tires, brake discs and brake lining for wear below manufacturer's limits.
Finalizing the deal:
With the inspection completed and a defect
list in hand, now is the time to finalize the deal. Depending on the purchase agreement, the
vendor usually pays for the correction of airworthiness defects. This can be in the form of adjusting the
purchase price accordingly or paying for the repairs. Non-airworthiness defects are at the
discretion of the purchaser.
In many cases, after the inspection and the
repairs have been completed, an annual inspection can be signed off for the
airplane.
