The Australian Transport Safety Bureau (ATSB) has been unable to determine why the fuel flow reduced in a Cherokee Six, causing the aircraft to lose power and crash near Moorabbin in June last year.
VH-CWK was on its fourth circuit when the engine lost power passing 500 feet on climb out. The pilot conducted a forced landing, but struck a tree on approach to a cleared area. The aircraft was destroyed and the pilot seriously injured.
The final investigation report released today showed that the fuel flow in the aircraft reduced to 22 lph from a peak of 113 lph, but the ATSB was not able to find out why. Fuel flow never decreased to zero, so fuel starvation was ruled out.
All tanks in the aircraft carried sufficient fuel with the right main selected and investigators could find no fault with the function of the fuel system.
After the engine lost power, the pilot targeted a glide speed of 90 KIAS and searched for a landing site within a 30° either side of the nose. They then identified one of few clear areas within gliding range, but as the aircraft approached the area, the pilot recognised contact with trees was unavoidable.
“This accident highlights the challenges pilots face when confronted with a loss of engine power at low level and with few suitable forced landing areas within the glide capability of the aircraft,” said ATSB Director Transport Safety Stuart Macleod.
“It reaffirms to pilots that they can best mitigate the effects of a loss of power through forward planning, which reduces mental workload under stress, and always maintaining control of the aircraft.”
ATSB investigators also discovered that an incorrect variant engine had been fitted to CWK, but believe it didn't contribute to the power loss.
The full report is on the ATSB website.