EH101 Merlin accident

[RotorPilot]

I was wondering if somebody "inside" could add something to that unfortunate "crack" in the tail rotor of a EH101 Merlin.

 

Any news about why it happened ?

 

RP

[Lu Zuckerman]

To: RotorPilot

 

Any news about why it happened ?

 

Because it was never considered as a possibility and the design was never changed to prevent it from occurring.

 

:unclesam:  :confused: This is Pierre.  He is still waiting to be recovered from the offshore platform.

[Heli-Ops]

Lu,

 

Can you enlighten us a little on what you are referring to.

 

Heli Ops

[Lu Zuckerman]

To: Heli-Ops

 

Any military or civil aircraft design program requires that a Product integrity program be initiated.  This consists of performing a Reliability analysis, A Failure Mode Effects and Criticality Analyses, and a Safety Hazards Analysis.  The Reliability analysis determines the predicted failure rates for the various components that go into the design.  Once the failure rates are determined the FMECA is initiated whereby for every predicted failure rate the modes of failure are determined and how the failure is both manifested and the method of detection.  On a properly run program the modes of failure are discussed with design engineering and they determine from the FMECA what redesign is necessary to minimize the effects of the failures or the failure mode is also eliminated.  Once the FMECA is complete and engineering has made the necessary changes the systems safety engineer will perform the hazards analysis to determine the frequency of catastrophic occurrence.

 

On the EH-101 program the Product Integrity Lead man felt that I had embarrassed him in a meeting with Westland and as a result he told the men in the group not to talk with me and eventually he had them remove all catastrophic failures from the FMECAs.  Since there were no catastrophic failures noted the Safety Hazards Analyses did not contain catastrophic failures and the helicopter was certified but without catastrophic failures even being considered in the design.

 

It should be noted that all of the catastrophic failures that lead to the EH-101 crashes were all noted in the original FMECAs

 

 

:unclesam:  :cheers: This is Pierre.  He is having a beer with the pilot that rescued him from the oil rig.