An ATSB report published this week concluded that the pilot of an A32 Vixxen contributed to a forced landing by delaying a diversion after experiencing a drop in oil pressure.
Aeroprakt A32 VH-VIK was on a private flight from Moruya to Griffith, NSW, in April last year when the pilot noticed low oil pressure on the Rotax 11.4 nm north-east of Canberra. Instead of landing at Canberra, the pilot continued the flight and monitored the oil pressure.
After 10 minutes, the oil pressure continued to decrease, forcing the pilot to divert to Tumut. However, the engine failed during the powered descent, which resulted in the pilot having to land in a field short of Tumut Airport. The pilot sustained minor injuries and the aircraft minor damage.
ATSB investigators attended the scene because the Vixxen was VH-registered, but were unable to determine why the oil pressure was lost. Instead, the ATSB investigation focused more on the pilot's actions, in particular the decision to continue rather than land at Canberra when the problem was first detected.
“For any issue that could lead to a loss of engine power, pilots should consider a precautionary landing at the nearest suitable location,” said ATSB Director Transport Safety Kerri Hughes.
“Flight over inhospitable terrain should be avoided, and pilots should maintain altitude whenever practical to improve their chances of finding a suitable landing place should their engine fail.”
Investigators also queried the decision to make a powered descent to Tumut rather than using the remaining engine power to keep altitude during the diversion.
"This meant that, when the engine failed, there was insufficient altitude remaining to glide to the runway,” Hughes said.
During an interview with the ATSB, the pilot said they had been reluctant to land at Canberra because they were concerned with flying over a populated area, the presence of passenger aircraft and a lack of familiarity with controlled airspace.
The pilot initially attributed the oil pressure loss to slower than usual airspeed during a scenic leg and lower outside air temperature.
The full investigation report is on the ATSB website.