Schweizer 269C-1 Post Flight Engine Checks
All owners and operators of Schweizer 269C-1 helicopters.
This Continuing Airworthiness Notice (CAN) is issued to highlight the importance of performing the idle speed and idle mixture checks in section 4.14 of the Schweizer 269C-1 helicopter AFM after the last flight of every day.
This CAN is prompted by UK CAA Safety Notice No. SN-2011/01 which was issued after an investigation of a fatal overseas Schweizer 269C-1 training flight accident. The investigation revealed the main rotor speed had decayed before impact due to a loss of engine power which was most likely caused by incorrect idle speed and/or mixture settings.
The aircraft manufacturer states that it is important to carry out the idle speed and mixture checks at the last flight of every day because if either the idle or mixture settings are incorrect, a loss of engine power could result if engine idle were selected in flight. Furthermore, the manufacturer also stated that it is important to perform the idle speed check at the end of the flight rather than only prior to flight, because the engine response is different when the engine is at normal operating temperature.
The CAA recommends that owners and operators of Schweizer 269C-1 helicopters review the post flight requirements in section 4.14 of the helicopter AFM and ensure they operate their aircraft in accordance with all the requirements in the AFM.
For further background information on the subject of this CAN a copy of UK CAA Safety Notice Number: SN-2011/01 can be obtained from: http://publicapps.caa.co.uk/modalapplication.aspx?catid=1&pagetype=65&appid=11&mode=detail&id=4428&filter=1(external link)
