True AN26 near Coxs Bazar on Mar 9th 2016, engine failure on takeoff, lost height on go-around and impacted waters

Last Update: April 20, 2017 / 15:17:47 GMT/Zulu time

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Incident Facts

Date of incident
Mar 9, 2016

Classification
Crash

Cause
Engine failure

Airline
True Aviation

Departure
Coxs Bazar, Bangladesh

Destination
Jessore, Bangladesh

Aircraft Registration
S2-AGZ

Aircraft Type
Antonov An-26

ICAO Type Designator
AN26

A True Aviation Antonov AN-26, registration S2-AGZ performing a cargo flight from Coxs Bazar to Jessore (Bangladesh) with 4 crew and a load of shrimps, was climbing out of Coxs Bazar's runway 35 when the left hand engine failed prompting the crew to stop the climb and join a right hand downwind for a return to Coxs Bazar's runway 35. The crew needed to go around however and were about to again join a left hand pattern for runway 35 when the aircraft lost height and impacted the waters of the Bay of Bengal about 2nm from the aerodrome. Two crew were rescued alive, one died after delivery to hospital, the other is in hospital care in critical condition. The bodies of the other two crew members were recovered from the wreckage.

True Aviation operates two AN-26s registrations S2-AGA and S2-AGZ, it is unclear which one was involved although local aviation sources assume it was S2-AGZ.

On Mar 10th 2016 Antonov reported that the aircraft involved was S2-AGZ. The aircraft had last been inspected in September 2015, it's operating life was until Jun 15th 2017. The aircraft was owned by Air URGA and was operated by True Aviation.

On Mar 10th 2016 Ukraine's Civil Aviation Authority reported that the cargo AN-26 crashed at Coxs Bazar belonged to Air URGA and had 4 Ukrainian crew on board, 3 of the occupants died in the accident. Ukraine's accident investigation bureau have accredited a representative and joined the investigation.

A pilot on the ground watching the events unfold told The Aviation Herald, that it was foggy at the time of the departure and accident of S2-AGZ, visbility was reported by tower at 800 meters however appeared more like 400 meters to the observing pilot. There are no METARs for Coxs Harbour, pilots only have the weather information available via tower. The left hand engine failed shortly after the aircraft became airborne prompting the crew to join a low level right hand downwind (to the east of the aerodrome over the town) for runway 35 at about 300 feet AGL. Turning base and final the aircraft descended to about 200 feet AGL and became visible from the ground while on final to runway 35, however maintaining 200 feet AGL as the crew could not establish visual contact with the runway, the left hand propeller was in feather position and not turning, the right hand propeller and engine were working normally, the power on the right hand engine increased, the landing gear was retracted at which point the observing pilot realized they were going around. The aircraft disappeared out of view having been airborne for more than 20 minutes at that point. A few moments later the engine sounds faded away. The aircraft impacted waters at high speed in a westerly direction at a sandy shoal about 1 to 1.5 nm west of the aerodrome, right hand wing first which separated from the aircraft. The rest of the aircraft flipped over and came to rest on its side nearly inverted, the left hand engine separated from the aircraft too and came to rest about 50 meters from the aircraft. The slat/flaps mechanism of the aircraft was found in full landing configuration suggesting the flaps/slats were either not retracted during the go-around or were re-extended for a ditching attempt. The pilot added that there is information going around, that the aircraft was overloaded, significantly impairing the aircraft's performance on single engine, True Aviation's management however is likely to deny the aircraft was overloaded. The cargo owners issued a bounty for every box of shrimps, not surprisingly all boxes were recovered by local fishermen.

On Apr 18th 2016 Ukraine's NBAAI reported the left hand engine failed shortly after departure from Coxs Bazar. The crew attempted to return to Coxs Bazar, however, the final approach failed for unknown reasons, the crew decided to go around. During the go-around the aircraft collided with the water surface about 3nm from the runway. The navigator received serious injuries, the other members of the crew were killed in the impact. The NBAAI is assisting the investigation by Bangladesh's authorities.

On Apr 20th 2017 the Air Accident Investigation Group Bangladesh (AAIGBD) released their final report concluding the probable causes of the crash were:

- Failure to initiate a rejected take off during take off roll following the indication of engine failure;
- Failure to adhere to the company SOP following the detection of the engine failure during take off;
- Considering the poor visibility at Cox’s Bazar Airport, diverting to the alternate airfield Chittagong Airport located only 50 nm away that has the provision for full ILS approach facility. This could have helped the crew in carrying out a proper one engine out precision approach landing;
- The aircraft flew at a speed much lower than the clean configuration speed. The aircraft flew at 225 km/h in clean configuration whereas the minimum clean configuration speed is 290 km/hr.
- As per the FDR data the aircraft stalled while making a turn towards the side of the failed engine at a very low altitude;

The AAIGBD reported the left hand engine's power spontaneously reduced from takeoff to cruise power as the aircraft accelerated through 80kph (43 KIAS) evidenced by the according decrease of oil pressure in the torque meter system. Despite the engine problem the crew continued takeoff. During the initial climb the engine power gradually reduced further, at about 300 feet the left hand propeller feathered due to the complete failure of the left hand engine within 60 seconds of the onset of engine problems. The crew attempted to return to runway 17 but were unable to align the aircraft with the runway, aborted the approach and joined a right hand downwind at 1000 feet MSL cleaning the aircraft up and accelerating to 300 kph (162 KIAS). The crew subsequently configured the aircraft for landing about 3.5nm from the runway, joined the final approach for runway 35, the captain however decided to go around about 1.2nm before the runway threshold, the surviving navigator stated in later testimonies that he could not explain the reasons for the go around as the aircraft was completely stable on final approach at about 300 feet and 1.2nm from the runway threshold. Flaps and gear were retracted according to both the flight data recorder and video footage available showing the aircraft in the go-around. The flight data recorder as well as the navigator confirmed the aircraft was maintaining about 300 feet MSL at a speed of 225 kph/121 KIAS (minimum clean speed 290 kph/157 KIAS). Tower cleared the aircraft for a left downwind, however, did not receive any reply. During the turn (into the failed engine) the aircraft entered stall - the navigator reported his last instrument reading was at 60 feet and 215 kph (116 KIAS) - and impacted waters about 10:43 minutes after departure and about 1:25 minutes after the go-around from final runway 35, the navigator stated the crew found it difficult to control the aircraft during the final stages of flight. ATC kept calling the aircraft until receiving information of the crash through other sources about 37 minutes after departure of the aircraft.

The captain (57, ATPL, 13,315 hours total, 6,896 hours on type) was assisted by a first officer (27, CPL, 1,438 hours total, 1,195 hours on type), a flight engineer (36, FEL, 3,924 hours total, 2,946 hours on type) and a navigator (48, FNL, 3,924 hours total, 2,946 hours on type).

Flight Data and Cockpit Voice Recorder were sent to the NBAAI for read out, due to internal damage the CVR could not be read out. The FDR was read out without problems.

The AAIGBD reported the design bureau of the engine manufacturer performed a borescopic inspection of the failed engine and determined that the combustion chamber and turbine showed damage. The 10th stage of the engine compressor showed damage to the guide blades. The cause of the engine failure, also based on testimony by the navigator, possibly was lack of lubrication by engine oil, a more detailed analysis might have been possible with the FDR and CVR available.

The AAIGBD reported the aircraft carried the maximum payload of 4800kg and stated: "There was no load sheet available to verify aircraft’s load, fuel or Take Off weight. The operator on enquiry informed that the load sheet was on board the aircraft and perished with the aircraft when it crashed. As per regulations three copies must be prepared before departure. One copy is to be left at the departing station, second copy is to be retained with the flight document and one copy is to be kept at the arriving station."