A Boeing 747-357 was operating a charter flight between Medinah-Mohammed Bin Abdulaziz AIrpott (Saudi Arabia) to Dhaka-Zia International Airport (Bangladesh) on this day in aviation history in 2008 Onboard, a crew of 18 and 307 passengers.
The burned engine #3 and the fire damage around the engine (Source and © IAAIB)
After an uneventful flight, the aircraft landed at Dhaka and rolled out to taxi speed. About 50 seconds after touchdown, ATC contacted the crew querying the crew if the aircraft was under control. The crew stated, in response to ATC's question, that the aircraft was under complete control. They also asked ATC what the problem seemed to be. ATC then informed the crew a fire was visible in the area of the right-wing and that the airport fire service had alerted. At the time At the same time, a #3 engine fire warning was presented to the crew. The crew carried out the necessary memory items and the first fire extinguisher was discharged into the engine. The other engines were also shut down and 20 seconds after the discharge of the first fire extinguisher the second fire extinguisher bottle was discharged into the #3 engine. The captain called the purser to the flight deck via the passenger address system, after which he instructed the other cabin crew to remain seated. When the purser got to the flight deck, the captain briefed him on the situation and asked him to go and evaluate the situation and to initiate an evacuation if necessary. When the purser returned to the main deck he saw fire and smoke outside the aircraft and, using a megaphone as the aircraft was depowered by now, order an evacuation of the aircraft. All passengers evacuated the aircraft without serious injury, 15 passengers and 2 crew members sustained minor injuries. The airport fire service arrived at the aircraft 2 1/2 minutes after being alerted and extinguished the fire using 1050 litres of foam and 38.000 litres of water from three attending crash tenders.
Fire fighting takes place while the aircraft is being evacuated (Source and © IAAIB)
The damage to the area around and including the #3 engine (right-hand inboard) was extensive. The aircraft was evaluated and declared beyond economical repair. An investigation was launched by the Icelandic Aircraft Accident Investigation Board (IAAIB), (state of registry of the aircraft) after an initial investigation by the Civil Aviation Authorities of Bangladesh (CAAB). The CAAB delegated the investigation to the Icelandic safety investigators. Their report is available on their website and can be accessed by clicking here. During the investigation, a fuel leak was discovered where the main fuel line for the #3 engine is coupled to the front spar. Upon disassembly the following findings were made;
One of two required retaining rings missing
The O-ring was not installed correctly, possibly nor providing adequate sealing of the connection
Left: coupling as found on the incident aircraft. Right: coupling as per Maintenance Manual. (Source and © IAAIB)
The following findings as to the cause and contributing factors were listed in the report;
Incorrect assembly of the flexible half coupling at the front spar of engine No. 3.
Retaining ring missing in flexible half coupling at the front spar engine No. 3.
Lock wire fastened in such a way that the coupling nut might rotate slightly.