The value of positive information

19/08/2012 — 1 Comment

This post is part of the Airbus aircraft family and system safety thread.

I’m currently reading Richard de Crespigny’s book on flight QF 32. In he writes that he felt at one point that he was being over whelmed by the number and complexity of ECAM messages. At that moment he recalled remembering a quote from Gene Kranz, NASA’s flight director, of Apollo 13 fame, “Hold it Gentlemen, Hold it! I don’t care about what went wrong. I need to know what is still working on that space craft.”.

The crew of QF32 are not alone in experiencing the overwhelming flood of data that a modern control system can produce in a crisis situation. Their experience is similar to that of the operators of the Three Mile island nuclear plant who faced a daunting 100+ near simultaneous alarms, or more recently the experiences of QF 72.

The take home point for designers is that, if you’ve carefully constructed a fault monitoring and management system you also need to consider the situation where the damage to the system is so severe that the needs of the operator invert and they need to know ‘what they’ve still got’, rather that what they don’t have.

The term ‘never give up design strategy’ is bandied around in the fault tolerance community, the above lesson should form at least a part of any such strategy.

Trackbacks and Pingbacks:

  1. Technical Lessons from QF32 | QF32 - September 24, 2015

    […] Install a “LAND ASAP” push button on the ECAM control panel, that inverts the logic (QF32 p198) and gives the pilots the minimum essential instructions to land/ditch immediately.   (R&D) (See another discussion on this topic) […]

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