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ASN Wikibase Occurrence # 195133
Last updated: 7 October 2019
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Date:29-APR-2017
Time:12:40 LT
Type:Silhouette image of generic A139 model; specific model in this crash may look slightly different
AgustaWestland AW139
Owner/operator:Abu Dhabi Aviation
Registration: A6-AWN
C/n / msn: 41213
Fatalities:Fatalities: 0 / Occupants: 3
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:Arabian Gulf, 8nm off Mubarraz Island, off Abu Dhabi -   United Arab Emirates
Phase: En route
Nature:Non Scheduled Passenger
Departure airport:Dhabi II Offshore Installation
Destination airport:BUNDUQ Offshore Installation
Narrative:
An AgustaWestland AW139 helicopter, registration A6-AWN, departed Abu Dhabi International Airport, with two flight crewmembers and five passengers, for Dhabi II oil rig, located 33 nautical miles (nm) off the coast of Abu Dhabi in the Arabian Gulf. Four passengers disembarked after arrival at Dhabi II at 1231 LT, and the aircraft continued towards oil rig BUNDUQ, approximately 78 nm further north-west.
One minute into the climb after departing from Dhabi II, the flight crew received a high oil temperature warning for the main rotor gearbox (MGB) at approximately 490 feet (ft). The observed oil temperature was 109°C, when the commander discontinued the climb and selected to descend to 500 ft. This action was taken to reduce power and the load on the MGB and was advised in the quick reference handbook (QRH). The flight crew decided to divert to the closest heliport, on Mubarras Island, 18 nm from Dhabi II.
Because the oil temperature continued to increase, the commander decided to descend to 200 ft in preparation for a possible ditching. While descending through 210 ft, and with an oil temperature of 119°C, the flight crew heard a loud grinding noise emanating from the gearbox area. The commander followed the instruction in the QRH and decided to ditch the aircraft.
The crew activated the aircraft flotation system prior to touchdown, and the inflated bags kept the aircraft afloat during the evacuation of all occupants into the life raft, from where they were rescued by the coast guard. As the left aft float slowly deflated, the Aircraft started to tilt and capsize.
The investigation identified that the causes of the deflation were a tear of the bag fabric and seam delamination. It was identified that the in-flight activation of the flotation bags was not compliant with the certification of the aircraft’s flotation system, which caused the deployed float cover to fragment. The remains of the float cover probably caused a tear to the aft left flotation bag. The investigation also identified that many flotation bags did not pass inflation tests during regular shop visits because of seam problems.

The Investigation further identified that the MGB oil temperature increased because the MGB oil cooling fan failed due to bearing damage, which resulted in the loss of airflow through the oil cooler. As a result of the accident, the aircraft manufacturer issued initial instructions and additional maintenance tasks for the early detection of MGB oil cooling fan failures.

Sources:

https://www.pprune.org/rotorheads/594100-ada-aw139-ditched.html
http://www.thenational.ae/uae/investigation-into-helicopter-ditching-off-abu-dhabis-mubarraz-island
http://aerossurance.com/helicopters/ada-aw139-a6awn-ditching-2017/
https://gcaa.gov.ae/en/ePublication/admin/iradmin/Lists/Incidents%20Investigation%20Reports/Attachments/106/2017-2017-%20Preliminary%20Report,%20AAIS%20Case%20AIFN-0004-2017,%20A6-AWN.pdf
http://aerossurance.com/helicopters/aw139-a6awn-ditching-uae/
https://www.gcaa.gov.ae/en/ePublication/admin/iradmin/Lists/Incidents%20Investigation%20Reports/Attachments/118/2017-2017%20-%20Final%20Report,%20AIFN-0004-2017,%20A6-AWN%20Accident.pdf

Safety recommendations:

Safety recommendation SR01/2019 issued 14 January 2019 by GCAA to Leonardo Helicopter Division
Safety recommendation SR02/2019 issued 14 January 2019 by GCAA to GCAA
Safety recommendation SR03/2019 issued 14 January 2019 by GCAA to EASA
Safety recommendation SR04/2019 issued 14 January 2019 by GCAA to EASA
Safety recommendation SR05/2019 issued 14 January 2019 by GCAA to EASA
Safety recommendation SR06/2019 issued 14 January 2019 by GCAA to EASA


Revision history:

Date/timeContributorUpdates
01-May-2017 13:44 Aerossurance Added
17-May-2017 09:14 Aerossurance Updated [Location, Departure airport, Destination airport, Source, Narrative]
12-Jun-2017 19:06 Aerossurance Updated [Time, Location, Departure airport, Destination airport, Source]
12-Jun-2017 20:10 Aerossurance Updated [Destination airport, Narrative]
06-Feb-2019 11:07 harro Updated [Narrative, Accident report, ]
09-Feb-2019 15:49 Aerossurance Updated [Source]
14-Feb-2019 14:46 Aerossurance Updated [Embed code]

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