Why this Rex plane’s propeller dropped off mid-flight

An aeroplane’s propeller which fell off during a flight above Sydney last year was “an extremely rare event”, the ATSB says.

The plane lost its propeller 19km from Sydney airport. The propeller missed houses and cars and landed in forest. The plane landed safely in Sydney. Picture: Supplied

The final report on the mid-flight loss of a propeller by a Regional Express (Rex) aircraft over Sydney last year has found fatigue cracking in the propeller shaft went unnoticed because maintenance engineers were not told to look for it.

The March 17 flight from Albury to Sydney had 19 people on board, when it experienced vibrations from the right engine.

As the pilots went through the checklist the vibrations worsened, so the decision was made to shut down the engine.

A short time later the propeller came off about 19km southwest of Sydney Airport, landing in dense forest and luckily missing any houses or vehicles.

The Rex crew alerted Air Traffic Control and the Saab 340 landed safely in Sydney without injury to any passengers or crew.

Inspections subsequently found the propeller shaft had fractured due to a crack in a crucial mounting bracket.

The Australian Transport Safety Bureau report delivered today, found the engine manufacturer’s maintenance documents did not include specific inspection procedures to detect fatigue cracking of the propeller shaft.

In addition, the ATSB investigation found Rex’s inspection worksheets did not provide for the recording of inspection findings.

“Consequently, this may not have provided for the best opportunity to ensure potential defects were identified, recorded and monitored,” the report said.

Since the incident, engine maker General Electric has changed maintenance manuals to include more ongoing detailed inspections of the propeller shaft.

The United States’ Federal Aviation Administration also issued an airworthiness directive, requiring repetitive visual inspection of the main propeller shaft for affected engines.

Rex also undertook a variety of measures in response to the incident including a review of maintenance practices for propeller removal and installation, which identified several areas of improvement.

The report noted that the Civil Aviation Safety Authority had audited Rex twice since the incident, looking specifically at the airlines’ propeller maintenance practices.

ATSB chief commissioner Greg Hood described the propeller loss as an “extremely rare event” and commended the Rex crew for their response to the emergency.

“The captain and the first officer demonstrated a high level of professionalism in their airmanship, communication, co-ordination and application of the safety checklist procedures in their response,” Mr Hood said.

He said the safety actions undertaken by General Electric and Rex, would reduce the risk of such a thing ever happening again.