Computer-Related Incidents with Commercial Aircraft

The Aeroperu B757 Accident

2 October 1996

Synopsis AeroPeru Flight 603 took off from Lima, and almost immediately noticed problems with the air data. Without reliable air data readings from the usual sources, the aircraft eventually CFIT'd into the ocean. Evidence from the CVR transcript (in Spanish) and altimeters after the accident suggested the pilots were supposing they were much higher. The altimeters were recovered stuck at over 9000ft. Masking tape was found to be covering the left-side static ports, as shown in this JPEG picture, left there after a cleaning operation. There was initial speculation from various Peruvian authorities that there was a computer-related failure, which turned into acknowledgement that this was a non-computer-related failure mode when the tape was discovered. Another incident (thankfully not an accident) which involved a maintenance-induced common failure mode was that of an Eastern Airlines L-1011 out of Miami on May 5 1983, for which both the full NTSB Report and Synopsis are available below.

The information here is a resumé of known information, a high-level analysis of the failure modes of a B757 which would lead to an accident, details of the B757 pitot-static system, and a brief history of the news reports and statements made about this accident, for those whose interests stretch to the sociological. I would still recommend against attributing any cause prematurely (as had occurred and might still be occurring).

The CVR transcript (in Spanish) is also available.

A shorter note on this accident appeared in RISKS-18.51, the new findings were announced by Peter Neumann in a short note in RISKS-18.57, and my note detailing the latest findings appeared in RISKS-18.59