Sir - You wrote in the Airline Safety Review for 1996 (Flight International, 15-21 January, P31) that "-the year provided its ironies" - none more so, I feel, than the contribution of secondary radar to the Lima Boeing 757 fatal accident. I understand that, following a request for position and height, air-traffic control informed the flightcrew that it was at 19,000ft (5,800m) as the 757 hit the sea.
There should be a requirement for being able to test static and dynamic air-pressure sensors before take-off. The aircraft's instrumentation and systems are compromised if there is a fault, as is secondary radar - with all that implies.
JACK KARRAN
London, UK
Source: Flight International
