On 31 October 2012, the crew of an ATR42 on a handover airworthiness function flight out of Prague briefly lost control in a full stall with significant wing drop after continuing a prescribed Stall Protection System (SPS) test below the appropriate speed and then failing to follow the correct stall recovery procedure. Failure of the attempted SPS test was subsequently attributed to both AOA vanes having become contaminated with water during earlier aircraft repainting at a specialist contractor and consequently being constrained in a constant position whilst the SPS test was being conducted at well above the prevailing freezing level.