Abstract
CAS alert message ‘PSW FAIL’ shows up frequently during civil aircraft test flights. This thesis provides an in-depth study of the problem by describing the fault phenomena and analyzing the fault based on historical data, system principles, and fault tree analysis. For the AT version after IASC 2nd stage software upgrade, pressure release response is triggered on the wing anti-ice valve when unilateral throttle lever is pushed over 40 degrees with both PACKs off and both WAIVs closed. Test flight data will be analyzed and verified. With respect to the flaws of pressure release response, this study optimizes the logic of ECS IASC software by analyzing trigger mechanism, adding pressure release response pre-requisites such as both PRSOV shut and signals off, with no APR mode initiated, and not under single engine startup. The study of the thesis helps to essentially improve the software, avoiding frequent occurrence of the pressure release response, enabling an accelerated production test flight and delivery test flight of Civil aircrafts.
Highlights
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Summary
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