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ASN Wikibase Occurrence # 194241
Last updated: 23 October 2017
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Date:17-MAR-2017
Time:11:49 LT
Type:Silhouette image of generic SF34 model; specific model in this crash may look slightly different
Saab 340B
Owner/operator:Regional Express Airlines
Registration: VH-NRX
C/n / msn: 340B-291
Fatalities:Fatalities: 0 / Occupants: 19
Other fatalities:0
Airplane damage: Minor
Category:Serious incident
Location:19km from Sydney, NSW -   Australia
Phase: En route
Nature:Domestic Scheduled Passenger
Departure airport:YMAY
Destination airport:YSSY
Investigating agency: ATSB
Narrative:
A Saab 340B aircraft, registered VH-NRX was being operated as RXA768 on a routine passenger flight from Albury, New South Wales (NSW) to Sydney, NSW. On board the aircraft were 16 passengers and 3 crew.
About 55 nautical miles south-west of Sydney airport, the crew noticed uncommanded engine indications and began the necessary checklists. While undertaking the checklist items, the crew experienced minor vibrations from the right engine. These vibrations worsened as the checklist progressed and became visually evident to the First Officer. As a result the crew commenced the engine shutdown procedure. During the engine shutdown procedure, the propeller separated from the aircraft. The crew made a Pan-Pan call to air traffic control, and completed the engine shutdown procedure. The aircraft landed without incident at Sydney airport.

An inspection of the aircraft by the ATSB at Sydney airport identified that the propeller shaft had fractured, leading to the separation of the propeller.

On 21 March 2017, the NSW Police Aviation Support Branch (PolAir) undertook a search operation for the separated propeller. The propeller was located in an area under dense forest about 8NM south-west of Sydney airport.
The propeller was found with the flange section of propeller shaft secured to the propeller assembly and a fracture through the propeller shaft.

The engine manufacturer’s preliminary metallurgical analysis of the fractured shaft has identified that fatigue cracking in the propeller main shaft originated within a dowel pin bore that was located on the forward face of the propeller flange from the propeller reduction gearbox (PGB). Their analysis indicates that the initiation of fatigue cracking within the hub flange may be associated with a combination of factors that include:

the accumulation of significant operational hours for each propeller reduction gearbox
the development of pitting corrosion damage within the dowel pin bore and at the front face of the propeller flange
progressive wear and subsequent surface damage of the hub flange at stress-critical regions surrounding the dowel pin.
GE Aviation have released two service bulletins (SBs) to help understand the potential fleet risk for fatigue cracking in other CT7 PGB main propeller shafts.

Sources:

http://www.dailyadvertiser.com.au/story/4537889/propeller-takes-flight-forcing-emergency-landing/?cs=147
https://flightaware.com/live/flight/VHNRX
https://www.flightglobal.com/news/articles/picture-rex-saab-340-lands-safely-after-losing-prop-435277/
https://www.atsb.gov.au/publications/investigation_reports/2017/aair/ao-2017-032/

Safety recommendations:

Safety recommendation AO-2017-032-SI-01 issued 13 April 2017 by ATSB to


Images:




Photo: NSW Police

Revision history:

Date/timeContributorUpdates
17-Mar-2017 06:46 bidgee Added
17-Mar-2017 08:48 harro Updated [Embed code]
17-Mar-2017 09:05 Aerossurance Updated [Source, Embed code]
17-Mar-2017 09:05 Aerossurance Updated [Location]
17-Mar-2017 09:09 Aerossurance Updated [Time, Location, Source, Narrative]
17-Mar-2017 09:09 Aerossurance Updated [Narrative]
17-Mar-2017 09:58 harro Updated [Time]
17-Mar-2017 20:06 Iceman 29 Updated [Photo, ]
17-Mar-2017 20:08 Iceman 29 Updated [Photo, ]
21-Mar-2017 07:29 harro Updated [Narrative, Photo, ]
13-Apr-2017 19:20 harro Updated [Narrative]
14-Apr-2017 09:16 harro Updated [Embed code]
27-Jun-2017 18:30 harro Updated [Narrative]

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