As result of increased financial pressure on airlines over the last 10-15 years, there have been changes in the way maintenance organizations conduct their work. The number of maintenance employees per aircraft has been reduced significantly, even taking into consideration that the present fleet demands less maintenance due to increased quality and more efficient maintenance programs. Only in specific maintenance tasks, such as primary flight control work, is this ratio still more-or-less normal. For almost all other tasks, there are now just spot checks of 10-15% of the work actually performed by someone else. Multiple accidents have identified this as a contributing factor, including an incident in 2015 wherein an Airbus A319 lost both engine cowlings and caught fire during takeoff.
Contract maintenance personnel have economic incentives to seek out overtime to maximize their income. A large number of countries still have not set maximum duration working times for maintenance staff like there are for pilots. Due to tight daytime flight schedules, there is increasing pressure for nightshift operations (there is a known safety risk when working under pressure in night hours on complicated work) on the involved maintenance organization.
Long shifts and midnight hours have become a cultural norm in maintenance. Many mechanics will work 56 straight days before a 28-day rest period, without any intermediate rest days. Without changes in working conditions for maintenance, attempts to correct that fatigue will only have short-term benefits. In 2013, the FAA tested a fatigue countermeasures training program on maintenance personnel; while the program raised awareness of the dangers of fatigue, actual fatigue management declined within six weeks of training.
- Reduction in staff, economic incentives available to maintenance technicians plus shifts toward night schedules for critical maintenance increase the likelihood of fatigue and maintenance errors. Due to tight daytime flight schedules, there is increasing pressure for nightshift operations on the involved maintenance organization.
- Many countries still have not set maximum duration working times for maintenance staff like there are for pilots.
- Number of maintenance employees per aircraft has been reduced significantly. Only in specific maintenance tasks such as primary flight control work is this ratio is still more or less normal.
- Based on aircraft sales forecasts in non-Western markets, there will be a worldwide shortage of qualified maintenance personnel.
- The loss of experience, safety culture, and tribal knowledge may be a bigger issue than overwork and fatigue.
Corroborating sources and comments
Airbus Maintenance Briefing Notes – Human Performance and Limitations; http://www.airbus.com/fileadmin/media_gallery/files/safety_library_items/AirbusSafetyLib_-MAINT-HUM_PER-SEQ01.pdf
NTSB MOST WANTED TRANSPORTATION SAFETY IMPROVEMENTS
EVALUATION OF AVIATION MAINTENANCE WORKING ENVIRONMENTS, FATIGUE, AND HUMAN PERFORMANCE
William B. Johnson Felisha Mason Galaxy Scientific Corporation
Steven Hall Embry-Riddle Aeronautical University
Jean Watson Federal Aviation Administration
20 January 2001
http://www.aviationpros.com/article/11303716/maintenance-and-fatigue-a-way-of-life (Draws the line between physical, mental, and emotional fatigue, and how they affect maintenance differently. Note in particular that the average rest time is 5-6 hours, and maintenance personnel as a whole aren’t aware that they’re not getting enough rest. Long shifts and midnight hours were cited as reasons for a maintenance mistake that caused the crash of Air Midwest Flight 5481, killing 21 people. Secondary inspections are recommended as a means of combating these mistakes.)
https://www.faa.gov/data_research/research/med_humanfacs/oamtechreports/2010s/media/201309.pdf (In 2013, the FAA and a private airline tested a fatigue countermeasures training program on maintenance personnel. While it showed short-term benefits in raising awareness and reducing fatigue, awareness significantly declined within six weeks. Demonstrates the prevalence of fatigue.)
http://aerossurance.com/safety-management/maintenance-personnel-fatigue/ (Advisory circular on fatigue. A UAE GCAA report found that personnel worked shifts of 56 days on, 28 days off, with no rest days in-between. Also calls to attention several accidents stemming from this issue in maintenance. Dated 2016.)