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Aircraft Maintenance: Pre-maintenance inspections

A friend of mine recently had some avionics work done on his Cessna Cardinal. The work was straightforward, removing the vacuum system and installing two new electronic flight instruments in place of the old attitude indicator and directional gyro. While enjoying his shiny new gadgets on the flight home from the avionics shop, air traffic control informed him that his transponder wasn’t working. So, he did a 180-degree turn and headed back to the shop.

Photo courtesy of Jeff Simon.

That’s when things got sticky. The shop surmised that the transponder had failed, possibly before the owner brought the aircraft to their shop, unrelated to the work they had done on the panel. John (not his real name) was sure that the transponder was working perfectly when the aircraft was handed over for the panel work. John was quoted a $1,000-plus flat fee for the manufacturer to repair the transponder and agreed to have it sent out. Time passed and the transponder finally came back from the manufacturer “NFF” (No Fault Found). Next, the avionics shop traced the problem to what they believed was a failed encoder. John’s frustration was growing, fingers were pointing, and John just wanted to get his airplane back with everything working and be on his way. Eventually, the shop decided to take full responsibility, fixed whatever the underlying issue was, and returned the aircraft to John without a bill for the additional “repair” work.

John’s story isn’t unique. Every time an aircraft is left in the care of a maintenance company, there is an assumption that the facility will take responsibility for issues that arise related to its work on the aircraft. However, identifying what issues are related to this work (and reasonably the facility’s fault) can be a significant challenge. Most general aviation aircraft are decades old and filled with potential gremlins just waiting to be unleashed as soon as mechanics begin to pull things apart. This is especially true for avionics work that can involve working with 40-year-old wiring. Even the simplest panel work is like pulling a loose thread on a sweater; soon, you might have more thread in your hand than sweater on your back.

The key to avoiding conflict is gaining mutual agreement about the condition of the aircraft at the time it’s handed over to the shop. This should be done formally, with a checklist that includes a walkaround outside (and inside) the aircraft to note preexisting scratches and dents, followed by an operational check of all the systems. If appropriate to the work being done, it should include a brief flight that tests all the systems and avionics. For example: If you are having any work done that could interface to your autopilot, it pays to conduct a “pre-work” test flight with the technician to prove that the autopilot is working perfectly before work begins. If there are post-maintenance autopilot issues, you’ll know that your autopilot isn’t to blame.

The same is true for mechanical repairs and especially for annual inspections. A pre-maintenance checkout flight can help identify squawks and clarify what is working fine before work begins. The process works and makes for a happier aircraft ownership experience. In a “proof point” of success, one owner noted a pronounced nose shimmy when picking up her aircraft from an annual inspection. The resolution was brief and simple: “You flew with me when I dropped the plane off. The nose wheel was smooth as silk.” The shop agreed, found the error in its work, and fixed it at no charge.

We can all take a lesson from car rental companies on this one. They learned long ago that the best way to avoid conflict is to do a walkaround condition inspection with their customers before handing over custody of the vehicle. It’s always amazed me how many people take that for granted with a $30/day rental car, but routinely drop off their $150,000-plus aircraft for maintenance with nothing more than handing the keys over to the line person.

Taking the time to do a pre-maintenance inspection and test flight can be frustrating to a busy shop. However, it is the only way to get everyone on the same page about the condition of the aircraft before work begins. So, make it a part of your routine every time that you hand over custody of your pride and joy. Spending some extra time with the technicians who care for your aircraft can be very valuable…you never know what you’ll learn! Until next time, I hope you and your families remain safe and healthy and wish you blue skies.

Jeff Simon

Jeff Simon

Jeff Simon is an A&P, IA, pilot, and aircraft owner. He has spent the last 17 years promoting owner-assisted aircraft maintenance and recently certified the FlexAlert Multifunction Cockpit Annunciator. Jeff is also the creator of SocialFlight, the free mobile app and website that maps over 20,000 aviation events, $100 Hamburgers, and educational aviation videos
Topics: Ownership, Maintenance, Airworthiness
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