Hersman notes the attention given to the flight crew and the major effort recently undertaken to update flight and duty time regulations for Part 121. But she says this attention also needs to be given to other safety-sensitive areas.
NTSB had previously made recommendations covering duty time limitations in maintenance, and the issue was debated in the late 1990s. At the time, the consensus was that more studies were necessary. But board member Mark Rosekind notes those studies have been accomplished. “What’s frustrating to us is we are going at this piecemeal,” he says of duty and rest regulations. “We knew this was an issue a decade ago and haven’t seen any action.”
In addition to improper installation of the bolt, the safety board cites as the probable cause the improper use of the bolts and nuts. Manufacturers provide detailed instructions on proper torque and reuse of nuts and bolts. But some of the nuts found at the crash site were worn beyond manufacturer guidelines for reuse. A subsequent investigation of 13 Sundance helicopters found that half of the nuts did not meet requirements.
This led to FAA releasing a general aviation maintenance alert in November about proper use of hardware such as nuts and bolts, and the agency is preparing a second, broader aviation alert on the same subject to be released earlier this year.
Sundance has since changed its policy to prohibit the reuse of the nuts.
Board member Robert Sumwalt further questions FAA’s role in providing adequate oversight. “Where were they? They weren’t there,” he says, adding, “Things that [are] getting attention are those things that get done properly.”
NTSB issued three recommendations to FAA: establish duty time regulations for maintenance personnel in Parts 121, 135, 91 (K) and 145 that cover start time, workload, shift changes, circadian rhythms, adequate rest time and other factors; encourage operators to implement best practices for conducting maintenance under Parts 121, 135 and 91 (K) that include use of work cards to detail maintenance tasks and other recording and verification of each task; and mandate maintenance personnel to receive initial and recurrent human factors training that cover human error causes such as fatigue.