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ASN Wikibase Occurrence # 176407
Last updated: 20 September 2021
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Type:Silhouette image of generic A333 model; specific model in this crash may look slightly different
Airbus A330-343
Owner/operator:Singapore Airlines
Registration: 9V-SSF
MSN: 1609
Fatalities:Fatalities: 0 / Occupants: 192
Other fatalities:0
Aircraft damage: None
Location:130 NM southeast of Hong Kong -   Hong Kong
Phase: En route
Nature:Passenger - Scheduled
Departure airport:Singapore-Changi Airport (SIN)
Destination airport:Shanghai Pudong International Airport (PVG)
Investigating agency: TSIB Singapore
Singapore Airlines flight SQ836 suffered a temporary loss of power on both Rolls Royce Trent 772B-60 engines while en route between Singapore and Shanghai, China.

The Airbus A330-300 aircraft was flying from Singapore to Shanghai, China as Singapore Airlines flight SQ836. The aircraft was cruising at 39,000 feet over international waters about 130 NM
southeast of Hong Kong, with a heading of 028 degrees. The flight crew observed weather cells along their flight route. They planned to deviate to the right to avoid the weather cells and requested Air Traffic Control (ATC) for clearance to turn right to a heading of about 080 degrees. ATC granted the request.
Sometime after the aircraft had turned to 080 degrees, the flight crew, taking into consideration the weather radar information, decided on a route that would bring the aircraft through the weather but that would avoid areas of higher weather cell intensity. They requested ATC for clearance to turn left to a heading of 020 degrees, which was granted. The flight crew turned to 020 degrees at 12:56:34 hours. They prepared the aircraft for possible turbulence by turning on the seat belt sign in the cabin and making an announcement through the public address (PA) system. They also set a target aircraft speed of 0.78 Mach, which was the turbulence penetration speed recommended by the aircraft manufacturer. As a further precautionary measure, they turned on the wing anti-ice and selected continuous ignition for both engines.
Subsequently, the aircraft entered a weather cell. The aircraft engines experienced surges while in the weather cell. The flight crew first became aware of a surge when they saw the aircraft’s Electronic Centralised Aircraft Monitoring (ECAM) displaying a message indicating that Engine No. 2 (the right engine) had surged and the message was accompanied by a list of response actions to be executed by the flight crew. The first response action was to reduce the Thrust Lever from Climb Thrust detent to Idle detent to reduce engine thrust. However, before the flight crew could complete the first response action, the ECAM message was displaced by a second ECAM message indicating that Engine No. 1 (the left engine) had surged, together with a list of response actions by the flight crew
The ECAM message pertaining to Engine No. 1’s surge was displayed above that pertaining to Engine No. 2’s surge. As such, the flight crew carried out the list of response actions pertaining to Engine No. 1’s surge.
This led to a point where the flight crew had to decide whether to shut down Engine No. 1. As the ECAM message pertaining to Engine No. 1’s surge was still displayed, the flight crew believed that Engine No. 1 was still in a surge condition and therefore decided that they would need to shut down the engine. FDR data showed that Engine No. 1 had actually self-recovered in the meantime but this was not known to the flight crew.
The flight crew declared Mayday to ATC and then shut down Engine No. 1.
With only one engine functioning normally, it would not be possible to maintain a cruise at 39,000 feet. So the flight crew, with ATC’s clearance, descended the aircraft to a cruise level of 26,000 feet.
The flight crew considered the options of diverting to Hong Kong or Guangzhou and continuing to proceed towards Shanghai. They noted that diverting to Hong Kong or Guangzhou would involve flying through weather cells again. They also noted that proceeding to Shanghai would pass by Xiamen and Hangzhou, which could be used as a diversion airport if needed, and that the route toward the northeast appeared clear of weather.
Thus, the flight crew decided to continue to proceed to Shanghai.
While cruising at 26,000 feet on their way towards Shanghai, the flight crew managed to restart Engine No. 1. Engine parameters appeared normal and the flight crew cancelled the Mayday.
When the aircraft was approaching Xiamen airport to the northeast, an assessment on the status of the aircraft was carried out and the flight crew consulted with the operators’ control centre via satellite communications.
The flight crew noted that the engine parameters all appeared normal, and maintained their decision to fly to Shanghai. The aircraft landed in Shanghai without further incident.
Data from the aircraft’s Flight Data Recorder (FDR) showed that both engines surged and recovered in quick succession. All in all within a span of 12 seconds, Engine No. 2 surged three times and Engine No. 1 two times, and Engines No.1 and No. 2’s first surges occurred at about the same time at 12:56:56 hours, which was about 22 seconds after the aircraft’s left turn to a heading of 020 degrees.
- The two engines encountered engine surges, one after another, while the aircraft was passing through an area of adverse weather.
- The engines, as per design, recognised the engine surges and selfrecovered immediately.
- Engine No.1 was disassembled and the examination of the engine suggest that the engine surge in Engine No. 1 was most likely a result of the release of IPC rotor path abradable lining material. Although Engine No. 2 was not disassembled and examined, it is most likely that Engine No. 2, being as new as Engine No. 1, experienced the engine surge for a similar reason.
- The release of the abradable lining material into the combustion section of the engine resulted in a disruption of airflow through the compressor section.
- The “Eng Stall” ECAM message was timed to display for 60 seconds whether or not the engine had self-recovered.


Accident investigation:
Investigating agency: TSIB Singapore
Status: Investigation completed
Duration: 3 years and 2 months
Download report: Final report


Singapore Airlines Airbus A330-300 flight #SQ836 on May 23 lost power on both engines south-east of Hong Kong and...

Posted by on Tuesday, 26 May 2015


Photo of 9V-SSF courtesy

Singapore - Changi International (WSSS / SIN)
30 January 2019; (c) Anton Homma

Revision history:

26-May-2015 17:40 harro Added
26-May-2015 18:39 harro Updated [Embed code]
01-Aug-2018 19:49 harro Updated [Time, Total occupants, Location, Narrative]
04-Aug-2018 07:42 harro Updated [Source]

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