Aircraft Maintenance: Risk management for mechanics

A 2016 Bureau of Labor and Statistics study found that aviation mechanics were nearly five times more likely to be injured on the job than pilots. The fact is that mechanics work in a dangerous environment filled with running engines, spinning propellers, and airplanes on jacks; as well as noise and chemical exposure risks that can cause long-term health issues if not properly managed.

An aircraft came into the maintenance shop after the pilot experienced a momentary loss of power while airborne. In spite of repeated ground runs, the shop was unable to reproduce the power loss on the ground. Some work was done on the aircraft to check and repair a number of potential causes of the issue, but no “smoking gun” was identified that was positively linked to the failure. Following the work, the mechanic conducted a successful ground run. He then decided to perform a post-maintenance check flight. On climb out, the engine lost all power and the aircraft crashed, severely injuring the mechanic.

In another case, a pilot reported having issues getting the prop to reach the desired rpm. No vibration was noticed by the pilot. The maintenance shop performed a ground run to duplicate the problem, thinking that the issue was most likely with the prop cable or governor. Upon closer inspection and removal of the spinner, it was discovered that the propeller hub had severe cracking. I shudder at the thought of the injuries that might have occurred had the prop come apart during ground testing, before the propeller hub cracking was discovered.

These examples highlight the inherent risks involved with aircraft maintenance. I recently discussed the subject with Ric Peri, vice president of government and industry affairs for the Aircraft Electronics Association. As an aircraft mechanic for more than 35 years, he has broad experience in both the regulations and processes for safe maintenance practices. According to Peri, the solution lies in taking the time to follow the manufacturer’s maintenance manuals. Mechanics typically do an excellent job of following maintenance manuals for repairs. Diagnostic procedures are a different story.

Aircraft owners don’t like paying for diagnostic time. This leads them to look for mechanics that will just “know what’s wrong” based on the symptoms. This approach ignores the fact that nearly every manufacturer has carefully designed diagnostic procedures to identify problems systematically and safely. The pressure to rely solely on experience during troubleshooting can be a safety trap. By skipping steps and trying to guess at the solution, mechanics run the risk of attempting ground runs or operational check flights without having ensured that the problem has been resolved and the aircraft is safe to operate.

As mechanics, aircraft owners bring us symptoms and squawks. It is our job to listen to the owner, investigate the issue, and chart a path to return the aircraft to airworthy condition. In a busy shop with both time and money pressures, it can be tempting to rush ahead in an effort to get the airplane out of the hangar and keep the customer happy. However, it’s important to remember that a mechanic’s own safety matters as much as the family that will be flying in the airplane once it leaves the shop.

With that in mind, we need to change the paradigm. Rather than searching for “expert” mechanics (the “airplane whisperers”), we should be rewarding mechanics who follow systematic maintenance procedures with our business. Not only will this increase safety, but it will often result in the most cost-effective repairs that avoid throwing parts at a problem until something works.

Whether you’re a pilot or a mechanic, safety matters. It’s what ensures that we all come home safe and sound at the end of the day to the people who matter most. Until next time, I hope you and your families remain safe and healthy, and I wish you blue skies.