Logbook Research: It's not just an AD search any more

Logbook Research It's not just an AD search any more By Joe Hertzler The maintenance records of an aircraft are the single most important factor considered when evaluating an aircraft for purchase. The value of an aircraft can be affected...

Logbook Research

By Joe Hertzler

The maintenance records of an aircraft are the single most important factor considered when evaluating an aircraft for purchase. The value of an aircraft can be affected significantly when maintenance records are incomplete, missing, or just plain sloppy.

This is the first of a two-part series that will outline and discuss the logbook research process in an effort to help you identify inadequacies in maintenance records that can impact an aircraft's value. In this issue, we will look at organizing the records in preparation of the research and some of the things to consider.

Are the records complete?
Once you get your hands on the logbooks, you first need to know if all the records are there. A complete set of maintenance records from the standpoint of the FAA is defined by 14 CFR Part 91.417. However, that outline should be considered a minimum requirement. You will find with the records, among other things, bound logbooks, maintenance release documents (yellow tags and 8130-3's), FAA form 337's, Airworthiness Directive Compliance records, and many times some sort of compliance status report created by someone else who researched the records previously.

Note: If you find a status report that someone else created, we recommend that you use it solely as a guide to direct you to legal signoff statements contained in the official logbooks, and even then, not until you have completed a second pass through all the logbooks.

First write down the aircraft make, model, and serial number and list below it each of the Class I Products (i.e. each engine and propeller) (Ref CFR 21.321, (b)), by make, model, and serial number, currently installed on the aircraft. It is a good idea to visually verify the part numbers and serial numbers of the aircraft, each engine and each propeller to make sure they match what the records say.

Next, separate the maintenance records for the aircraft, each engine, and each propeller into individual areas on the table. Place the logbooks for each in order by date and on a sheet of paper record the start and end date for each logbook.

Warning: Many of the old bound logbooks have separate areas for maintenance and inspection. In those cases, the work sometimes does not flow through the logbook from beginning to end. Some technicians use the logbook as designed and enter inspections in the inspection section and maintenance in the maintenance section, which places the entries out of chronological order.

After recording the timeline for the aircraft, engines, and propellers logbooks, look closely to identify any significant gaps. Records should flow from one logbook to the next with no significant gap. When a significant gap is found, check the gap in aircraft time as well. Sometimes an aircraft will sit for a while and not get used. However, if there is a six-month gap along with 200 or 300 hours of utilization or more, for example, without any maintenance, make a note of the inconsistency so that questions can be brought up later.

Try to place the maintenance release documents with each applicable logbook, i.e. aircraft, engine, or propeller, so that they are well organized for your research. If you find any FAA form 337 documents, place them in a separate group and order them by date. Many times, the owner of an aircraft will keep the FAA form 337 documents in the aircraft flight manual or operation handbook in the weight and balance section. If the 337's are in the flight manual, we recommend that a copy of each be made and a binder created and kept with the logbooks just for 337 forms. These days, many 337 forms include instructions for continued airworthiness and such instructions should be with the logbooks.

Accurate times and cycles
The next step is to establish the current times and cycles for the aircraft, engines, and propellers. We have many times found an engine to have 500 to 1,000 more or less cycles than the owner thinks, and likewise with hours. Although the aircraft time can usually be derived using the hour meter in conjunction with the maintenance records, the owner should provide the current landing count for the aircraft.

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