AAIB investigation to ATR 72-212 A, 500 Version, G-COBO
Loss of control, 5 nm north of reporting point ORTAC, 21 December 2016.
Summary:
皇冠体育app aircraft was on a scheduled flight from Guernsey to Manchester. While climbing to a cruising level of FL170 the aircraft began to accrue airframe icing. 皇冠体育app crew were presented with a DEGRADED PERF and an INCREASE SPEED caution. 皇冠体育app appropriate checklists were not fully actioned and the correct climb speed was not maintained because the crew focused on climbing the aircraft clear of the cloud and icing conditions. 皇冠体育app aircraft experienced an in-flight upset whilst levelling at FL130 (as requested by the pilots) and commencing a turn instructed by ATC. 皇冠体育app aircraft was subsequently recovered to controlled flight, after which the crew elected to return to Guernsey. 皇冠体育appre were no injuries.
皇冠体育app loss of control resulted from airframe icing accrued during the climb and incomplete use of the appropriate checklists, leading to selection of an unsuitable speed followed by the use of the LNAV mode of the flight director to initiate a turn.
皇冠体育app operator and manufacturer took several safety actions, including an amendment to the aircraft鈥檚 checklist and operating manuals.
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