Human Factors Challenges

General aviation and airline maintenance solutions

GA maintenance organizations work on hundreds of aircraft types and models. Each aircraft often has a 30+ year collection of modifications and supplemental type certificates that may need checking. A sign-off for an annual inspection essentially certifies the aircraft and its component documentation for all work since the aircraft was new. One saving grace for GA paperwork is companies like ATP. Such technical publishers assemble the documents from government and manufacturers to streamline the search for proper requirements and procedures. However such companies can only provide the documents. Companies and AMTs must make the commitment to follow the procedures.

Airlines, MROs, and GA maintenance service suppliers must ensure logistical access to readable/usable documents. Availability of documents must be matched with a culture that values following procedures. Individual managers and AMTs can make a difference by always identifying procedures that are difficult or incorrect. Organizations and manufacturers must amend procedures as soon as possible. That action can help ensure that technical documentation is not only high value but also perceived as high value by the maintenance workers that use them.

2. Fatigued workers

The workshop delegates ranked fatigue as the second largest risk to safe work. The fatigue challenge may be larger at MROs and airlines but GA is not immune. An FAA study in 1999-2000 collected more than 50,000 hours of data from airline maintenance and MRO workers and found that the average sleep was just over five hours/day. A 2006 study of the general American population showed that men get about six hours. Both numbers are well below the recommended eight hours of sleep per day.

The airline maintenance occupation, especially airlines, conducts a lot of night and early morning work. The combination of insufficient rest, long working hours, and middle of the night maintenance activity has a significant impact on worker performance. Since airliners must be maintained during the night the solution can be found in increased sleep duration and science-based scheduling. Other interventions, like napping, strategic use of caffeine, adjusting lighting, and matching rested workers to critical tasks are all partial solutions.

Both airlines and general aviation mechanics have been using the FAA’s computer-based fatigue countermeasure training. The two-hour course, available at, has been used by more than 25,000 mechanics. There are a number of U.S. and international MROs and airlines that have made the fatigue training mandatory for all workers. The FAA also provides additional support for fatigue awareness at

3. Safety culture

The two words, safety culture, are easy to say but represent attitudes and programs that require significant corporate and individual worker commitment. It is characterized by a shared value in the importance of safety and the ability of every worker to articulate, understand, and perform their individual actions to ensure safety. A five-person GA shop or a 5,000-employee MRO can have a safety culture.

Whether you are maintaining airliners or small aircraft, the safety culture must be communicated from the senior executive level. A safety culture has ways for all personnel to report safety threats, errors, or even violations that may impact safety. The industrywide push for the application of safety management systems (SMS) will eventually have a positive impact on GA.

4. Event reporting data

It is difficult to discuss safety culture and SMS without talking about event reporting.

Safety management is a formalization of the safety process. It relies on the process of keeping excellent records, observing, and recording company performance. SMS uses appropriate key indicators to understand why something may have gone wrong, or to predict trends of impending issues. SMS can help companies to look at emerging threats using current data. This helps ensure continuing safety.

Airlines and MROs rely on key performance indicators (KPIs) to impact safety and financial decisions. Flight deck technology makes it possible to record every action of the pilot or aircraft. Airlines know the quality of nearly every take-off, approach, and landing. This can help with decision making about procedures, training, crew pairing, and more. Of course, the airlines can also watch engine and aircraft system performance to know temperatures, vibration, fuel flow, and hundreds of other data points. MROs and airline maintenance organizations can count maintenance-caused delays or returns, rework, warranty issues, and more. Even with all of this data, it is difficult to fully identify and understand the contributing factors of a maintenance discrepancy. For maintenance performance, human generated event reports are better than automated data collection.

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