THE INTERIM REPORT into the crash of a Rockwell/Daimler Benz Aerospace X-31 has identified a malfunction in the pitot-static system as the major contributory factor to the loss of the high angle-of-attack research aircraft (Flight International, 1-7 February).

Project accident-investigations are now believed to be centred on this system. Some project sources believe that the accident was caused by pitot icing.

The aircraft was returning to NASA Dryden Flight Research Center, in straight-and-level flight, when pilot Karl Lang detected false airspeed readings, followed by pitch oscillations. These increased and were followed by a violent roll before Lang ejected.

Source: Flight International