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Report: contaminated fuel causes A330 engine control problems and emergency landing at Hong Kong
17 September 2013
Cathay Pacific 780 following evacuation on runway 07L (photo: HK CAD)

Cathay Pacific 780 following evacuation on runway 07L (photo: HK CAD)

Contaminated fuel caused serious control problems on both engines  of an Airbus A330, forcing the crew to carry out an emergency landing at Hong Kong.

On April 13, 2010, Cathay Pacific Airways flight CPA780, an Airbus A330, was scheduled to operate from Surabaya, Indonesia to Hong Kong.  The accident aircraft uplifted 24,400 kilogram (kg) of fuel at Surabaya-Juanda Airport and took off at 08:24 local time. On board were 309 passengers and 13 crew members.

During the climb, the flight crew noticed some abnormal Engine Pressure Ratio (EPR) fluctuations on both engines with an associated ECAM message. After consulting with a maintenance engineer, it was decided to continue since all engine parameters were considered normal other than the EPR fluctuations. Almost two hours into the flight, the same ECAM message reappeared. Again the crew contacted a maintenance engineer and it was decided to continue the flight.
The flight was 110 nm from Hong Kong when amongst others an “ENG 2 STALL” annunciation was displayed on the ECAM. The nr.2 engine was set to idle and the nr.1 engine set to Maximum Continuous Thrust (MCT). However No. 1 engine N1 only temporary increased to about 57% N1 and then dropped back to about 37% N1. The flight crew declared “PAN PAN” and requested to shorten the track for a priority landing.
When approximately 45 nm southeast from Hong Kong at 8,000 ft AMSL, an ECAM message “ENG 1 STALL” was annunciated. The crew moved the thrust levers of both engines to check the engine control but there was no direct response from the engines. The No. 1 engine speed eventually increased to about 74% N1. The No. 2 engine speed remained at sub-idle about 17% N1.
During the approach to runway 07L the captain was unable to decrease the speed by retarding the No. 1 thrust lever.  Overspeed and ground proximity warnings were triggered during the approach.

CPA780 touched down on runway 07L at 13:43 hrs at a position between abeam Taxiways A4 and A5 and with a distance of around 680 metres from the beginning of the runway threshold at a ground speed of 231 kt. The landing wind was 143 degrees at 14 kt. Immediately after both main gears touched down on the runway, the right main gear bounced and the aircraft became airborne again briefly. The aircraft then rolled left seven degrees and pitched down to -2.5 degrees at the second touchdown during which, the lower cowling of No. 1 engine contacted the runway surface. Spoilers deployed automatically. Both engine thrust reversers were selected by the Commander. Only No. 1 engine thrust reverser was deployed successfully. Maximum manual braking was applied.
The aircraft came to a complete stop on the runway with its nose wheel at about 309m from the end of runway 07L. The total distance for stopping the aircraft from the initial touchdown was approximately 2,630m.
The crew shut down the engines and requested the tower controller to check for a possible wheel fire. There was no sign of fire. An emergency evacuation was then ordered just after 13:45.
One passenger sustained serious injuries in the evacuation while 56 passengers and six crew members sustained minor injuries.

The Hong Kong Civil Aviation Department’s Accident Investigation Division concluded that the accident was caused by fuel contamination. The contaminated fuel, which contained SAP (Super Absorbent Polymers) spheres, uplifted at Surabaya subsequently caused the loss of thrust control on both engines of the aircraft during approach to Hong Kong. These SAP sphere were used in the filter monitors installed in a fuelling dispenser at Juanda Airport.

The following chain of events and circumstances had led to the uplift of contaminated fuel to CPA780:
i. The re-commissioning of the hydrant refuelling system after the hydrant extension work in WARR had not completely removed all contaminants in the affected hydrant refuelling circuit. Salt water remained in the affected hydrant refuelling circuit.
ii. The re-commissioning of the hydrant refuelling system after the hydrant extension work in WARR was not properly coordinated which led to the premature resumption of the hydrant refuelling operations while the hydrant system still contained contaminant.
iii. The refuelling operation in WARR, in particular low flow-rate refuelling, DP recording and monitoring, did not fully comply with the international fuel industry latest guidance.
iv. A number of unscheduled filter monitors replacements after the premature resumption of hydrant refuelling operation were not investigated by the fuel supplier and hydrant operator at WARR.
v. The unusual vibration observed during the refuelling of CPA780 was not stopped immediately and properly investigated by the fuel supplier personnel.

The investigation also identified the following deficiencies and contributing factors that may cause possible fuel contamination:
i. There were no established international civil aviation requirements for oversight and quality control on aviation fuel supply at airports.
ii. There were no established international civil aviation requirements for refuel operational procedures and associated training for aviation fuel supply personnel.
iii. The manual monitoring of DP changes in a fuelling dispenser during refuelling was not effective.

 

More informtion:

Final flight profile of CPA-780 (HK CAD)

Final flight profile of CPA-780 (HK CAD)