Many plane listings will include scanned logbooks. If the listing doesn’t, you should request copies. Before diving in, make sure the logbooks are complete and cover everything from the plane’s first year to the present day. Gaps or missing logbooks are a deal-breaker. Without a logbook review, you have no way of knowing whether the plane is airworthy. To be legal, you would need to do all the inspections and comply with all outstanding ADs. You also won’t be able to evaluate the plane’s health well. Are there parts that tend to fail? Damage that needed to be repaired? Without complete logbooks, you can’t tell. It will also be harder to sell your airplane since almost all buyers will be leery of planes with problematic logbooks.
To do an initial logbook evaluation, do the following three steps:
Your first pass should be just like the start of a private pilot oral exam: determining airworthiness. At least the annual, transponder, and ELT inspections should be in order. Don’t fret if 100hr inspections are missing; they’re not required unless the plane operates for hire. It also tends to be a moot point for private owners, since most owners fly less than 100 hours a year and the 100hr inspection is the same as an annual. Also, check for current IFR inspections. A VFR-only seller might have skipped them, but if you plan to fly IFR you’ll need to get them. This could be a useful point when negotiating.
Next, delve further back into the past. Has the plane had oil changes every 50 or 25 hours? Do required inspections happen regularly? Is the owner diligent about recurring ADs? Are annuals generally clean, or do they tend to find discrepancies? You want to verify that the plane has been well maintained and that there are no recurring maintenance problems.
Then, zoom in on any major events in the plane’s life. If there was damage, was it repaired correctly? Are upgrades done properly? Your network is very useful here; don’t be shy about polling your network if you’re not sure how to interpret a log entry, plane-specific things to look out for, or a neutral opinion about whether damage is a deal-breaker.
337s
Whenever a plane has a major alteration or repair, the mechanic doing the work must file a 337 form with the FAA. The escrow company will probably give you copies of the 337s. You can also order forms on CD for $10 from the FAA at http://aircraft.faa.gov/e.gov/ND/. It’s worth going through the 337s and cross-referencing with the logs. They should match up nicely. If they don’t, it means that someone did major work on the airframe without logging it properly. At best that means a sloppy mechanic worked on the plane; at worst the plane is unairworthy or someone could have tried to hide damage history. Obviously, such discrepancies are a huge red flag.