UPDATED: Missing Saab prop found in bushland.
Steve Creedy - editor
21 Mar 2017
Australian carrier takes precautionary action after rare event.
A police helicopter has found a propeller that flew off a Regional Express Saab passenger aircraft as it approached Sydney on Friday.
The propeller was found in an area of bushland near housing at Revesby, south-west of Sydney, and air safety investigators are working with police to retrieve it.
The Australian Transport Safety Bureau said the propeller was found broadly in an area matching a trajectory calculated using information from the plane's flight data recorder.
The find came after Regional Express (Rex) on Monday said it would remove immediately remove from service propeller gearboxes and shafts in five other aircraft. It later issued a clarification saying it did not ground the aircraft but was carrying out the work over two or three days.
The propeller separated from the Saab 340B, which had 16 passengers and three crew on board, as the aircraft was on approach to Sydney airport and about 20kms south-west of the city.
The crew calmly followed standard operating procedures after declaring a PAN and landed the plane safely.
The airline said that it was still waiting for the Australian Transport Safety Bureau to determine a root cause of the accident but had decided “through an abundance of caution’’ to remove from service and quarantine all propeller gearboxes and shafts of the same series as the one involved in the incident.
The move affected five aircraft, two of them freighters, in addition to the one involved in the incident.
Rex also lashed out at what it called gross inaccuracies in media reports that claimed the aircraft should have diverted to Canberra and that its maintenance procedures should have detected flaws in the propeller shaft..
“As stated in our previous media release and as confirmed by the location of the propeller, the aircraft was some 20 km away from Sydney airport when the engine was shut down and the propeller separated from the aircraft,’’ it said. “It would be ludicrous for the pilot to divert the aircraft 250 km to Canberra airport when Sydney airport was just 20 km away.’’
The company said it stood by the decision made by the crew to continue to Sydney Airport, which was in full compliance with both regulatory and company requirements.
“Further, Sydney airport has a precision landing system, longer runway and more suitable runway orientation to cope with the prevailing strong winds.’’
The carrier also said it was premature to second guess the investigation with claims maintenance checks should have been able to detect the fault in the propeller shaft.
It said it had been fully compliant with engineering inspections prescribed by engine manufacturer General Electric.
Rex chief operating officer Neville Howell noted on Monday that the event was extremely rare and that the only other recorded similar event in 1991 involved US carrier Comcair.
In that case, the aircraft also landed safely after experiencing similar problems to the Australian crew. The failure was eventually traced to a sub-surface flaw introduced when an ingot was melted to make the part.
Howell said the airline placed great emphasis on emergency procedures during bi-annual training and the crew was well rehearsed to respond appropriately with a safe outcome.
The Saab 340 was also designed to climb, cruise and land on one engine.
“The crew demonstrated enormous composure and discipline under extraordinary circumstances, and I commend their professionalism,’’ he said. “The Captain displayed exceptional skills in landing the aircraft so smoothly in bad weather and strong winds, so much so that the passengers did not notice anything different.
“We would also like to thank the flight attendant and our staff at Sydney Airport for their assistance and support to our passengers.
“An audio clip of the exchange between the FO and ATC has been obtained by the media, and the entire aviation world is full of praise for the calm, collected and professional manner in which the young FO (first officer) interfaced with ATC (air traffic control). ‘’
The airline also released further details of the incident, confirming the engine had been performing abnormally when the crew shut it down.
The crew had feathered the propeller to reduce drag and it was at this point that the first officer saw it separate from its shaft.
“The propeller assembly was seen to rotate upwards and to the right,’’ it said. “The propeller was seen rotating in a horizontal position and then moving away without making contact with the aircraft.
“Both passengers and crew reported that the flight thereafter was smooth and the landing was normal in spite of bad weather at Sydney with winds exceeding 35 knots.’’
The airline said the propeller was found to have sheared off at the shaft and all the fittings of the main assembly were intact.
It had been in constant contact with Saab and engine manufacturer General Electric about the incident. The US National Transportation Safety Board had also been informed.