Maintenance and Certification

by DeborahAnn Cavalcante, Aircraft Maintenance Technology (AMT) contributor. This article was originally published in the March 2013 issue of AMT magazine and is reprinted with permission.

Fatigue for aviation maintenance technicians (AMTs)Footnote 1 comes in many different forms: physical, mental and emotional.

AMTs often work long hours under pressure, including working through the night. This often results in not just extreme fatigue but errors, some of which may potentially be life-threatening to pilots and passengers as well as to the AMTs themselves.

It is no secret that fatigue can come in different forms: physical, mental and emotional. Physical fatigue brings about muscle soreness, oxygen debt or extreme tiredness caused by sleep deprivation, illness or poor nutrition.

Many AMTs may experience the weariness of emotional fatigue resulting from performing undesirable tasks which may additionally be performed under trying conditions. High levels of focus and concentration associated with complex tasks create mental fatigue, which combined with the physical or emotional, leads to increased errors and risks in safety sensitive arenas.

There are a countless number of documented errors and accidents attributed to tiredness and fatigue in the maintenance workplace. Studies have shown that fatigue can have consequential effects on a person’s cognitive ability. Cognition refers to mental processes such as awareness, perception, reasoning and judgment.

Fatigue has drawn parallels to the effects of alcohol. In 2000, Williamson, Feyer, Friswell and Finlay-Brown conducted a study on driver fatigue and found that after 17 to 19 hr without sleep, performance on some tests was equivalent or worse than that at 0.05 percent blood alcohol content. Response speeds were up to 50 percent slower for some tests and accuracy measures were significantly poorer at this level of alcohol. After longer periods without sleep, performance reached levels equivalent to the maximum alcohol dose given to participants (0.1 percent blood alcohol content).

The findings reinforced empirically that sleep deprivation is likely to compromise decision-making ability and accuracy needed for safety on the road and in other industrial settings.

Further FAA studies and self-reporting by aviation maintenance mechanics indicate the average sleep for aviation maintenance mechanics routinely to be five to six hours per night, two to three hours short of the required eight hours per night. Additional studies reveal data that sleep deprivation is a cultural norm in the aviation maintenance workplace, although mechanics as a group are not generally cognizant of the fact that they do not get enough rest.

Fatigue-related accidents

One of the most notable aviation maintenance fatigue-related accidents occurred in 1990 when British Airways Flight 5390 experienced a windscreen blowout shortly after departure from Birmingham International Airport in the United Kingdom. The left windscreen, which had been replaced prior to the flight, was blown out under the effects of the cabin pressure when it overcame the retention of the securing bolts. Eighty-four of the 90 total bolts were of smaller than specified diameter.

The captain was sucked halfway out of the window at 18 000 ft and was miraculously restrained by the cabin crew while the co-pilot flew the aircraft to a safe landing at Southampton Airport (Air Accidents Investigation Branch report, 1992).

While the official accident report cited numerous contributing factors that led up to this incident, one of the most insidious was the effect of fatigue on the aircraft mechanic who conducted the task. The work was conducted very early in the morning at a time when the human body experiences a natural low, also known as circadian effect. This, combined with lack of sleep before his shift, may have contributed significantly to the aircraft mechanic’s perceptual judgmental error in selecting the wrong size bolts for the job and then justifying that decision by believing that the countersink was too big rather than the bolt was too small.

Air Midwest Flight 5481 crashed on takeoff killing 21 people. The NTSB concluded that the aircraft was tail heavy and the pilot was unable to keep the nose down because elevator travel was restricted due to improperly rigged flight control cables. The NTSB reported the maintenance work to the aircraft’s elevator system was performed on the midnight shift in the early morning hours.

Compounding the fatigue issues was the lengthy commute the employees made getting to the repair facility and long shifts that were routinely worked. Work had been performed on the elevator system and interviews with the mechanics indicated a number of shortcomings with maintenance procedures including lack of proper training, insufficient resources and the possibility that fatigue affected the quality of the work performed.

Education and training alone are most likely not enough to deter mechanics from working while fatigued when many organizations push their mechanics to work 14- to 16-hour days. A combination of pressures, including customer satisfaction, management pressure, time pressures along with interruption of revenue associated with the loss of use of an aircraft, seem to win out and override good common sense as well as documented safety policy and procedures.

Effective countermeasures

This begs the question and you may well be asking, what are effective countermeasures to not only cope with the problem, but reduce maintenance errors and enhance safety? Amazingly, they are simple but require commitment to a healthy lifestyle. Eating a balanced diet stabilizes energy levels and eliminates sugar “highs and crashes.” Don’t go to bed too hungry or too full, as this is definitely a sleep interruption and prevents deep solid rest. Use caffeine to increase alertness when you need it, but avoid it before bed, as its wakening effects can be long-lasting.

Exercise regularly, but not before bedtime as it increases energy levels. The “at-home” environment is a factor in allocating adequate undisturbed hours for sleep. This may take some coordination with family members and their respective schedules. Enhance your sleep environment with dark curtains, a quiet room; turn off the phone and set the room temperature to 65 to 68 F.

Although a healthy lifestyle goes a long way toward personal fatigue management, it alone may not be enough. As maintenance tasks are self-paced rather than externally paced, fatigue management becomes a partnership between the employer and the employee. As an industry, a re-evaluation and recognition of the cultural norm in the aviation maintenance world that no workday is too long, and a lack of required rest periods is detrimental to safety is well in order. Workplace factors include working hours, staffing levels and the availability of break periods.

Risk management

Effective fatigue risk management requires a partnership between the employer and the employee, as each can contribute uniquely to solutions (Dawson, 2000; Fletcher, 2007; Transport Canada, 2007b, 2007c). It is unrealistic to aim for “zero fatigue” in all cases. An appropriate objective for fatigue risk management is to ensure that risks are as low as reasonably practical (Stewart & Holmes, 2008).

The maintenance environment presents opportunities to modify methods of task performance—having secondary inspections or operational and functional checks, and rescheduling the most safety-critical tasks, or those most susceptible to fatigue, at times when fatigue will have the least impact.

We would be foolish to think we can avoid the reduced mental functioning brought about by fatigue. For this reason, bringing awareness and focus to the problem becomes critical in mitigating it. Commitment from all levels in the organization is essential.

Ultimately, the quality of work rests with the individual maintenance technician, who, by understanding the consequences of fatigue, is in the ultimate position to assure they are both well rested and have access to strategies to deal with maintenance fatigue.

DeborahAnn Cavalcante earned her Master of Aeronautical Science, with a specialization in Safety Management from Embry-Riddle Aeronautical University in Daytona, Fla., and her Bachelor of Science from Virginia Tech in Business and Risk Management.

FEELING TIRED? Time to revisit Transport Canada’s
Fatigue Risk Management System for Canadian Aviation - FRMS Toolbox

Transport Canada commissioned a set of tools and guidelines to help the Canadian aviation industry set up fatigue risk management systems. Fatigue risk management systems are based on the premise that it's everyone's responsibility to manage fatigue. Employers should make sure that work schedules give employees adequate opportunities for rest between shifts. In turn, employees are responsible for making sure they use those opportunities to get the sleep they need to be fit for work. Use the FRMS Toolbox today!



Footnote 1

AMTs = Aeronautical Maintenance Engineers (AMEs) in Canada.

Return to footnote 1 referrer

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