IvanK |
11-09-2011 11:52 PM |
Quote:
Originally Posted by Herbs107
(Post 360171)
Back in the 80's a RAAF Mirage 3's seat went off when it was in for maintenance in a hangar. At the time a engineer was standing on it and all 3 safety pins were in place. The poor guy didnt stand a chance! The seat was a Martin Baker, they never found out what caused it to go off, but during the investigation they also found that the pressure required to deploy the seat in a ejection using either of the igniter handles was so much that a normal person couldnt set it off. During their career with the RAAF a few Mirages were lost where the pilot never ejected, this may or may not have been the cause.
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Well I was there when the engineering Stuff up with Bottom handle pull off forces on the Mirage IIIO was found.
The original OM4 cartridge seat was up for replacement. Martin Baker suggested a drop in replacement MK10 with MDC (like the Belgians had already done) however the RAAF in its infinite wisdom (Saving $) decided no lets modify the OM4 to an OM6. This entailed adding the Rocket Motor pack. An additional component called a Remote Rocket initiator was added to the seat. All worked well on the test rig, but incredulously no over all system check was performed once the modded seat was fitted to the aircraft. In the Mirage III the first part of the sequence was to jettison the canopy 1 second !!!!! later the seat sequence began.
I was at 2OCU at the time as a Mirage FCI. OCU was the last squadron to have the moded seat fitted, furthermore the Simulator (Sim) was the very last cockpit fitted.
As part of the Students preparation for his first solo he was forced into an ejection decision. Students trying to pull the bottom handle on the modified Sim seat found they couldn't get full handle travel ... as a consequence the seat (as far as the Sim was concerned didn't fire) so the students all had unsuccessful ejections. So we instructors jumped in and voila there was the issue handle jammed after about 3cm travel. The Sim seat was written up as unserviceable. The Sim techs found the cause. When the handle was pulled The canopy jettison didn't occur as part of the mechanical components of the canopy jettison (A sear ) was impacting on the new Rocket Motor Initiation pack housing this in effect causing the seat pan handle to jam thus preventing ejection.
So it was then decided to do some pull off checks on real aircraft (with initiator cartridges removed) ... golly gosh same thing seat pan handle was jamming. .... We had been flying the aeroplanes post seat mod for 6 months like this ... not knowing Ejection was not possible !!. Eventually it was sorted and we got back to flying. It was however one of the most appalling stuff ups I ever witnessed, Fortunately prior to the discovery no one had the need to eject ... if they had it would have been very sad indeed.
I will never forget the morning brief when the Senior engineering officer briefed the assembled pilots on what had been found ... to say the mood was icy would have been an understatement ! Why no overall function check was carried out post mod still haunts me to this day.
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