On 11 November 2016, a Cessna 208B aircraft was on a re-familiarisation training flight with an instructor and trainee pilot on-board.
After take-off, at an altitude of about 500 ft, the instructor noted the climb speed reducing while the trainee continued to maintain the nose attitude for best angle of climb. At the same time, the instructor heard the engine lose power and a thin film of fuel partially obscured the windscreen.
As the airspeed reduced to 60 kt, the instructor took control and identified a suitable area for a forced landing and began a left turn at the target glide speed of 85 kt. At the completion of the turn, they selected 30 degrees of flaps to provide a short climb, which allowed the aircraft to clear two hangars and an area of trees.
After clearing the hangars and trees, the aircraft landed without further incident.
A post-accident examination of the engine found the number eight fuel nozzle locking plate missing—probably not reinstalled when fuel transfer tubes and nozzles were installed after replacement.
The missing locking plate allowed the fuel transfer tube to slowly migrate out of the nozzle adaptor over the 86 hours since the maintenance occurred. Fuel escaped, leading to engine power loss in flight.
Australian Transport Safety Bureau Chief Commissioner Greg Hood says the incident serves to underline the importance of ensuring all maintenance is completed entirely and correctly.
“The locking plate was not installed during scheduled maintenance, and yet the fuel leak did not develop for a further 86 flight hours,” he said. “This demonstrates how the effects of incomplete maintenance can take a long period of time to manifest.”
Read the report: Engine failure and forced landing involving Cessna 208, VH-TYV, Darwin Airport, Northern Territory, on 11 November 2016