Bristol Dash 8 Engine Flameout Incident (G-JEDD)

Incident Overview and Aircraft Details On 20 March 2001 at 1545 UTC, a DHC-8-311 with registration G-JEDD experienced engine flameouts at Bristol International Airport, Avon. The incident was investigated by the AAIB Field Investigation team, with the findings published in AAIB Bulletin No 1/2002. ## Operator Procedures and Checklist Issues The operator's normal checklist at the time indicated that Ice Protection/Ignition should be selected 'as required' during Line Up checks. An operational notice from 13 October 2000 advised that during icing conditions, open by-pass doors and select ignition to MANUAL immediately after engine start for series 100, 200, and 300 aircraft not incorporating the Auto Relight System. After this incident, the operator revised the aircraft checklist to include an additional check of ice protection prior to taxi. The investigation noted that had the ignition been selected manually to ON at this stage, it is unlikely that the engine flameouts would have occurred. ## Manufacturer Service Bulletin and Auto Relight System The Aircraft Flight Manual required engine ignition to be selected to Manual when operating in icing conditions, but this was not complied with in this incident. The commander had briefed to use Manual Ignition for take-off, however, the Line Up checks had not been completed prior to the engine flameouts. The aircraft manufacturer produced Service Bulletin No. 8-74-02 for the Installation of an Auto Relight System, which linked igniter operation to engine HP spool speed (Nh). With this modification, when condition levers are selected above FUEL OFF, the igniters automatically operate if Nh falls below a threshold value. The SB was incorporated at build from Aircraft Serial Number 541 and above; G-JEDD (serial number 533) did not have this modification at the time of the incident. ## Regulatory Response and Industry Actions The AAIB proposed that the incorporation of Service Bulletin No. 8-74-02 be mandated on all aircraft by Transport Canada. However, Transport Canada responded negatively, citing that current maintenance and operational procedures afforded an equivalent level of protection. They considered the choice between the two alternative ways of achieving the intent of the recommendation to be a business decision best left to operators. Within the United Kingdom, all operators of the Dash 8 elected to modify their aircraft in accordance with the SB to afford maximum protection from this type of event. The manufacturer also indicated it would revise and reissue DHC-8 Service Letters to highlight the importance of ensuring that engine intakes are clear of frozen contaminant prior to departure.