| Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation. |
What happened
On 13 February 2018, the pilot of a de Havilland DHC-1 departed Luskintyre, New South Wales (NSW) after conducting ground power tests. The pilot was the only occupant on board.
During initial climb, at about 100 ft above ground level (AGL), the engine lost partial power. The pilot lowered the nose of the aircraft while manipulating the throttle in an attempt to correct the power loss. Due to the proximity of fencing, trees, housing and roads immediately past the landing strip, the pilot elected to attempt a forced landing on an adjacent paddock 90 degrees to the right. The aircraft entered a stall, impacting the ground in a nose-down, right wing low attitude.
The pilot subsequently reported that an inspection of the carburettor identified a loose part had caused the priming float to jam in the open position, resulting in an excessively rich fuel-air mixture.
Figure 1: de Havilland DHC-1 post accident
Source: Pilot in Command
Safety message
Data illustrates that partial power loss in single-engine aircraft occurs three times more frequently than total engine failure. Due to unreliability of engine power in these circumstances, it can be advantageous to treat partial power loss as total engine failure and act accordingly. The ATSB website publication 'Managing partial power loss after take-off in single-engine aircraft' provides guidance on managing these situations. Pre-flight self-briefing is an important tool in reinforcing planned emergency actions, including in circumstances of unfavourable terrain immediately past the aerodrome.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.