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Troubleshooting Your Pilot

Posted 11 years 171 days ago ago by Admin

Troubleshooting your pilot…
By Scott Skola

Nothing brings a productive day to a screeching halt quicker than a broken aircraft. At the very core of getting the anomaly identified and corrected is that initial interaction between the mechanic and pilot.

By following a few simple suggestions you can fine tune these early communications, improve troubleshooting efficiency, and get the aircraft back online sooner.

Interaction 101

It’s hard to find specific information on how a mechanic and pilot should discuss aircraft discrepancies.  It’s not part of any posted curriculum, nor is it included in any FAA documentation.

There have been several articles on a similar topic - aircraft discrepancy management.  One article published in the ICAO Journal (Jan/Feb 2000 issue) summarized the results of a Purdue University survey that found the interaction between mechanics and pilots to be of high importance when reporting aircraft discrepancies.  However, it fell short in discussing how a mechanic and pilot should interact.

Another ongoing attempt at improving operational communication is through Crew Resource Management (CRM) training.  The FAA has recently finalized a rule that requires Part 135 operators to provide CRM training to all departments involved in support of aircraft operations.  However, even this program currently does not offer specifics.

Bottom-line, even though the above examples recognize the importance of mechanic / pilot communications, they do not specifically address the initial interaction between these two groups.

So where do we begin?

The Discrepancy

In a perfect world the pilot will encounter a fault, discuss the issue with a mechanic, and the problem will be solved quickly.  However, as often found in the real world, the pilot is limited in his duty time, or has already left for the day. Or worse, the pilot is stuck on an offshore platform or at some remote call scene.

How the pilot conveys the discrepancy to the mechanic becomes the foundation for this initial interaction.  Whether written in the logbook, discussed face to face, or described over the phone, how the pilot conveys the discrepency is the critical starting point in troubleshooting the issue.

In general, these interactions can be communicated two ways, either verbally or by logbook entry.

Verbal Discussion

Ideally, all initial interactions over aircraft discrepancies will involve some form of verbal discussion between the mechanic and pilot.

By far, face-to-face interaction is the easiest and most efficient method to begin troubleshooting an aircraft discrepancy.  Where words fail, the mechanic and / or pilot can revert to point and touch, run-up, or fly the aircraft, etc., in order to define the problem.  By the end of the interaction the pilot should be able to enter the appropriate logbook entry, and the mechanic should have a solid foundation to troubleshoot or repair the problem.

While having a live discussion is better for the mechanic than troubleshooting from a logbook entry, verbal interactions by phone or radio can present their own issues.

For instance, all initial exchanges should be limited to the actual discrepancy.  Now is not the time for secondary or other non-related information.  Each bit of relevant information the pilot can accurately supply to the mechanic will quickly narrow down the probable causes of the discrepancy.

After a successful interaction of this type, the mechanic will be able to assemble an appropriate flyaway kit to take with him, or better yet, possibly assist the pilot in determining if the discrepancy is an operational MEL candidate.

Unfortunately, sometimes verbal discussions can start off on the wrong foot.  Although personality issues account for most of these problems, occasionally it is merely a simple perception issue. For example, from a maintenance perspective, there are three popular notions that often lead to a conflict during an initial interaction with a pilot:

  • Using a comparison of one aircraft to another as the sole reason for a discrepancy - no two aircraft or engines are identical.
  • Non-acceptance of manufacturer operational limits - the limits are what they are…if it’s within limits the aircraft is airworthy.
  • Pilot proclaimed maintenance background creating a “show us, don’t tell us” mentality --- a mechanic will quickly pick up on a pilot’s maintenance experience by how he / she deals with and discusses the discrepancy.

The main goal in discussing this initial interaction is to improve the two-way communication between mechanics and pilots.  However, this cannot take place without some simple common sense and a little tolerance exhibited by both sides.

Logbook Entry

The most challenging interaction is a discrepancy logbook entry without any discussion with the pilot.  While thankfully not a common occurrence, trying to troubleshoot a fault based on written words alone can be a unique experience.

One of the biggest hurdles faced by the mechanic is interpreting the form and content of the actual write up.  This doesn’t mean the pilot should write a complete chapter in the logbook.  However, the entry must include enough detail to determine which specific system the fault has affected.

Developing a concise logbook entry can be as simple as a three-step process:

1)  Spend a moment reviewing the sequence of events leading up to the discrepancy, plus any relevant events after the fault was noted.

2)  Take those mental notes, condense them, and make a quick written statement of the problem on a piece of paper.

3)  Read it back and adjust as necessary.

Sometimes when making a discrepancy entry too quickly, like during an engine cool down period, important supporting information is inadvertently omitted.

The importance of proper terminology and content in a logbook entry can be clearly illustrated using the discrepancy example shown in the title picture:

  • Poor: “Radio inop”
  • Good: “VHF inop”
  • Better: “#1 VHF fails to receive”
  • Excellent: “#1 VHF COMM fails to receive on 118.50”

As each entry example increased in detail, the troubleshooting time dramatically decreased thanks to the addition of only six words.  If the aircraft was equipped with two VHF COMM, two VHF NAV, and one FM radio, these extra descriptive words would reduce a potentially hours-long troubleshooting bonanza into a possible ten-minute #1 VHF COMM radio replacement.

Not only does a short, concise logbook entry reduce troubleshooting time, it also provides the basis for streamlining the required maintenance sign off once the discrepancy is corrected or deferred.

In the above example, the original write up would require a sign off for the function check of all radios, in addition to the actual one repaired.  Whereas by the final entry revision, all that is required is a simple #1 VHF COMM replacement sign off, or if applicable an MEL deferment sign off.  Either way, the aircraft is approved for return to service quickly.

Without a doubt, it takes both a mechanic and a pilot to make this system work.  The interaction between mechanics and pilots should be everybody’s priority as this is what keeps the aircraft flying, the customer happy, and just as important, the money rolling in.


The importance of using proper terminology cannot be overstated when discussing aircraft discrepancies.  Manufacturers’ terms, local slang, or any other descriptive terms are acceptable provided EVERYONE involved in the aircraft operation fully understands their specific meaning.

If during a discussion with the pilot, the mechanic mentions removing the Chinese hat from the flower pot and the pilot is left wondering if a new Charlie Chan gardening movie is coming out…well, that just doesn’t move the discussion in a positive direction.

Sometimes actual manufactures’ terms can also give rise to doubtful exchanges of information.  Recently a young aviator mentioned he might have had a CAM JAM.  As he had just transitioned into the Bell 407, we looked at each other with a raised eyebrow.  He must have sensed something was up because he blurted out that CAM JAM was in the flight manual.  Sure enough there it was…and we learned a new term for the day.

Another point of contention is the haphazard use of non-aviation terms when describing an aircraft problem.  A “puddle” is a pool of water that kids play in – it is not the correct term to use when describing “a puddle of hydraulic fluid under the nose strut” that can be measured in milliliters.  Dramatic license does not apply to aircraft discrepancies.

The main point here, if there is any doubt in what terminology to use, always follow the manufacturer industry standard or aviation authority’s descriptions, as these can be researched and specifically defined.

Foot notes:
(1) Article, http://legacy.icao.int/anb/humanfactors/Survey_results_suggest_2000.pdf

About the author: Scott has worked in various maintenance positions at a major helicopter operator for over 30 years.    When not at his 7&7 day job, he provides technical writing and research services through his business TEK Aviation LLC, and can be contacted at [email protected]