>>Preliminary examination of the aircraft by German investigation agency BFU has revealed that the aircraft was undergoing a test of its hydraulic system following indications of a leak.
As part of the test a locking pin was inserted into the nose-gear strut to prevent retraction while the landing-gear retraction mechanism was activated from the cockpit.
But a spokesman for BFU says that the movement of the nose-gear doors led to the pin’s becoming “disconnected” from its position. While the pin remained intact, he says, it was no longer able to prevent the nose wheels from retracting.
BFU is studying the design of the pin which, says the spokesman, had not been supplied by Boeing but which had been specially-made...
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Wow, sounds like a repeat performance of the SIN NWA incident I described above, down to the "specially-made" part:
http://aviation-safety.net/photos/di...0&vnr=2&kind=I