Originally Posted by
turboshafts
Yes but the extended TBO several times induces a
higher risk of failure, and leads to a probable connection to the failure incident
Fatigue cracks in a new MRA and MGB is less probable due to the breakdown
statistics of the helicopter type. The breakdown incidents in the past support this.
Also the part of the MRA where the suspension bar fitting is broken,
it coincides with the part of the Outer planetary gear on the epicyclic module
that has a crack that cannot be explained by an other probably cause than a gear failure. If the suspension bar came loose and that ultimately leads to a gearbox failure,
it could be anywhere on the outer planetary gear of the epicyclic module, but it is not.
...Abolutely, as an engineer it is impossible to argue against what you say. If it were 2009 I think this would be an entirely sensible approach.
The problem is that it is 2016 the only way we could continue as normal is to persuade the passengers that reducing the TBO would be enough to ensure their safety.
5 gear related accidents, 3 total loss fatalities worldwide in E&P since 2009, 4 of them on the same range of A/C.
Plus we have this from the AIBN...
"The nature of the catastrophic failure of the LN-OJF main rotor system indicates that the current means to detect a failure in advance are not effective."
a. Clearly we couldn't give them an absolute guarantee of no failures nor should we.
b. They won't be listening this time.
What will come out of this will be some form of industry wide initiative so that future aircraft have more reliable gearboxes.