3 ms·
TL;DR: This incident was, as usual, the result of multiple failures happening together. 1. An airspeed sensor starts outputting intermittent data spikes. This
by extension 15y ago
TL;DR: This incident was, as usual, the result of multiple failures happening together.
1. An airspeed sensor starts outputting intermittent data spikes. This is a software failure, but they still don't know what caused it. There is some theory about high energy particles hitting the CPU. It seems very strange to me that a critical system like this can output garbage data and nobody knows why.
2. The flight control computer usually detects these spikes and filters them out by using the last good data for the next 1.2 seconds. However, at the end of the 1.2s, it assumes that the input from the sensor is good. If another spike is occurring at the moment it switches back, it isn't detected. That seems like a rookie mistake to me. I've definitely run into the same sort of issue in other contexts -- handling a second event while reacting to the first one.
- ypcx 15y agoHappened in November 2010 in the timespan of 4 days. (I think there were even more but this is what I remembered I can quickly grab from http://goo.gl/FgcAv http://goo.gl/FgcAv) 11/4: Quantas Airlines Grounds All Airbus A380s After Engine Fire Over Indonesia http://www.huffingtonpost.com/2010/11/04/qantas-airbus-problem-ai_n_778719.html http://www.huffingtonpost.com/2010/11/04/qantas-airbus-probl... 11/5: Engine Problems Hit Second Quantas Aircraft -- This Time a Boeing 747-400 http://www.reuters.com/article/idUSTRE6A435P20101105 http://www.reuters.com/article/idUSTRE6A435P20101105 11/8: Quantas Uncovers More Engine Problems http://www.abc.net.au/news/stories/2010/11/08/3059568.htm http://www.abc.net.au/news/stories/2010/11/08/3059568.htm