Human Factors Training for Engineers (Mechanics)

[SASless]

Sundance Helicopters, a Tour Operator in the Las Vegas NV area, lost an aircraft and all aboard when a bolt fell from the Fore/Aft Cyclic Flight Control Linkage with the cause being attributed to the Re-Use of a Self Locking Nut and the absence of a Cotter Pin.

How well is your Helicopter preflighted.....and does your maintenance providers re-use Self Locking Nuts?



Aircraft Accident Report: AAR-13-01 (http://www.ntsb.gov/investigations/summary/AAR1301.html)


http://www.ntsb.gov/doclib/reports/2013/AAR1301.pdf

[spinwing]

Mmmmm ...

Probably one of the first things an 'new chum' AME gets to learn is 'how to assess the (re) usability of self locking fasteners' ...

In this case the bolt should have been 'failsafe' by the use of a 'self locking nut' AND a 'split cotter pin' .... on top of that (certainly outside of the US) most maintenance organisations and responsible authorities require that a "Duplicate Inspection' be carried out (and certified for) on 'any flight control or any control that may affect the safety of flight' before the aircraft is released to service.

Somewhere here the system broke down ..... badly !!! :=

[Chopper Doc]

No split pin? Gulp! That is unforgiveable.

[ericferret]

Sadly nothing new in the report.
Not that many years since a UK jetranger crashed where the cause was stated to be the reuse of worn nuts on the tail rotor drive. The subsequent loss of a nut and bolt lead to a loss of the tail drive. No split pins here so you wonder about the integrity of a critical system with only a single locking device. Are 206's still like that? I haven't seen one for years.

[FSXPilot]

If you're talking about the Thomas Coupling then yes still no split pins!