It could take weeks – even months – until safety officials pinpoint what caused a Singapore Airlines' Boeing 777 to catch fire after returning to Singapore on Monday.
Dramatic video has since emerged via social media, showing flames engulf the wing of the Boeing 777-300ER as passengers waited inside. It took fire crews “a few minutes” to extinguish the flames, allowing the 222 passengers and 19 crewmembers to leave the plane.
The incident occurred on Singapore Airlines Flight 368, which had been en route to Milan when the pilots chose to return to Singapore about 3 hours into the flight after they received an engine oil warning, according to the airline.
Shortly after landing back in Singapore, the right engine of the Boeing 777 caught fire. A passengers recorded the incident on video, which was shared via social media and appeared to show damage to the wing and engine.
Passengers waited on board several minutes – up to 10, according to eyewitness accounts – as firefighters arrived and extinguished the flames.
"The blaze was quite fierce and we waited for around two to three minutes before the fire engines arrived," Flight 368 passenger Lee Bee Yee said to The Straits Times of Singapore. "Surprisingly, all the passengers were quite calm. The SQ (Singapore Airlines) crew was very professional in calming everyone down."
No one was harmed in the incident, according to local reports.
Now the focus will turn to just what could have caused such an incident in the first place.
One analyst told Reuters it appeared the cockpit crew of the 777 “followed the right procedures” by returning to Singapore after receiving the safety warning. The plane dumped fuel and landed in Singapore after about 4 hours in the air.
“When the plane slows down as you land, fuel can cling to the wing and surfaces,” Greg Waldron, Asia Managing Editor at industry publication Flightglobal, said to Reuters. “Sparks from the hot brakes after they landed could have the triggered the fire and it does appear quite dramatic. But they appear to have gotten that under control very quickly,”
“There don’t appear to be any procedural issues here,” Waldron added.
Engines on 777 aircraft, a workhorse of many carriers' international fleets, have occasionally failed and caught fire in recent years. But the engines have been from different manufacturers and could be for different reasons, which is why investigators strive to determine precisely what happened in each incident.
On May 27, a Korean Air Lines Boeing 777-300ER had an engine fire while preparing to take off from Tokyo to Seoul. The pilots rejected a takeoff because of an engine fire that spread debris on the runway, and the Japan Transport Safety Board is investigating, according to a roundup by the Aviation Safety Network.
News videos showed a portion of engine cowling missing from one of the Pratt and Whitney engines. But the fire was extinguished within 30 minutes and the 319 people aboard evacuated without serious injuries.
A slightly different version of the plane, Boeing 777-200ER, flying as British Airways Flight 2276, suffered an engine fire at the Las Vegas airport on Sept. 8, 2015. The 170 people aboard evacuated without serious injuries.
The National Transportation Safety Board is still studying the incident in conjunction with British investigators, but they initially found a problem with one of the GE90-85B engines. A portion of the high-pressure compressor in the engine failed, which sent fragments through the engine casing and cowling, investigators said Oct. 6.
GE is performing high-priority, focused inspections of the compressor from other engines, to determine what else needs to be done, investigators said.