§ Mr. Michael McNair-Wilson
asked the Secretary of State for Defence, pursuant to the speech of the Under-Secretary of State for the Armed Forces on 22 July during the debate on the Royal Air Force, if he will give further details of the incident in 1971 involving a door on one of the Andovers of the Queen's Flight; what modifications were introduced then to prevent a similar occurrence; and what modifications are currently being carried out.
§ Mr. Wiggin
The minor accident in 1971 to which my hon. Friend refers happened to an Andover of 32 Squadron, not of the Queen's Flight. The mechanism of an Andover door includes three locking mechanisms; the primary lock consists of four claws which secure the door, the secondary mechanism anchors the primary as a precaution, and the barostat interlock independently prevents the doors from opening during flight. In the 1971 accident either the primary or the secondary locks had not been operated properly. No modifications were introduced as a result of this accident since none were judged necessary.
Following an accident in 1981 to a Dan Air HS 748, the civil version of the Andover, the air crew and engineering practices were examined and slightly amended to include a double check on electrical checks and a double check on the barostat mechanism. I should say, however, that training procedures have always emphasised exhaustive checking. As a consequence of the same accident, we are introducing minor modifications to the door structure, replacing an aluminium strike plate with one of stainless steel, and replacing round headed with countersunk rivets to reduce slightly the wear on the locking mechanism.