Quill Shaft failure

[A 109 C]

I have seen two similar cases of quill shaft failure, on different engines, of the same helicopter, with an Allison engine. In both cases, the quill shaft sheared instantly on pressing the starter button, even before N1 could register. The previous flight did not have any warning of gene failure. Any one ?

[paco]

Was that on the AS 355? or something else?

Phil

[A 109 C]

No, it was A 109 C

[VeeAny]

I know of an aircraft that a similar thing happened to, it turned out to be an unnoticed vibration somewhere between engines and gearbox, broke an oil line and shortly afterwards (like 1 or 2 hours) broke the shaft on the Starter Generator.

[vfr440]

You absolutely have to have 2 people to fit the start/gen. One to hold it in engagement with the splines and the other to get than damned silly clamp around the flange and adaptor plate. If there is only 1 x person the start/gen hngs on teh shaft and it WILL shear. MM warns about this.

Simples!!:) -VFR

[PEASACAKE]

This is such a common problem that I recommend that all AS355 and A109 operators keep a (NEW) spare quill shaft in the boot with the oil and blanks, keep the tools to change it there as well.

They will always shear away from base and with passengers on board.

I must have changed 20 in the last 10 years.

VFR440 you are spot on.

[ironchefflay]

tthe quill shaft sheared instantly on pressing the starter button, even before N1 could register. The previous flight did not have any warning of gene failure. Any one ?

there will be no warning of a shaft shearing. they will shear immediately on start due to the torque required to overcome the inertia. happens on CT-7's also. frequently.