JAL B738 at Sapporo on Feb 23rd 2016, smoke from right hand engine prompts evacuation on taxiway

Last Update: January 31, 2018 / 17:23:21 GMT/Zulu time

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Photo of JAL Japan Airlines JA322J, Boeing 737-800 — JAL Japan Airlines JA322J, Boeing 737-800 (Photo credit: Kentaro IEMOTO@Tokyo / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Feb 23, 2016

Classification
Accident

Airline
JAL Japan Airlines

Flight number
JL-3512

Departure
Sapporo, Japan

Destination
Fukuoka, Japan

Aircraft Registration
JA322J

Aircraft Type
Boeing 737-800

ICAO Type Designator
B738

A JAL Japan Airlines Boeing 737-800, registration JA322J performing flight JL-3512 from Sapporo to Fukuoka (Japan) with 159 passengers and 6 crew, was taxiing for departure from Sapporo in heavy snowfall when smoke emanated from the right hand engine (CFM56) which soon also invaded the aircraft cabin. The crew stopped the aircraft on the taxiway and initiated an emergency evacuation via slides including right hand slides. One passenger received serious, two passengers minor injuries in the evacuation.

The airline reported that during taxi for departure the right hand engine failed causing smoke to appear in the cabin and prompting the emergency evacuation.

Japan's Transportation Safety Board (JTSB) have dispatched investigators on site.

Passengers reported there was a smell of burning rubber at first followed by observation of smoke from the right hand engine and then smoke in the cabin. It appears the right hand engine may have contacted a snow pile while taxiing off the apron onto the taxiway.

Video footage presented by Japanese media does not show any evidence of an engine fire.

On Feb 24th 2015 the captain of the flight contradicted a police report, which had stated the aircraft had collided with snow causing the right hand engine to stop followed by a loud bang and smoke emanating from the engine when the engine was restarted. The captain stated that no restart of the engine had occurred.

The airline added, there was a bang from the right hand engine followed by smoke intruding the cabin prompting the emergency evacuation, although it was not clear whether the engine problem and smoke was linked.

On Feb 25th 2016 the JTSB reported that three passengers received injuries in the evacuation, one of them was serious (thoracic spine compression fracture). The JTSB is conducting an investigation into the accident.

On Jan 31st 2018 the JTSB released their final report concluding the probable causes of the accident were:

In this accident, it is probable that while holding on the taxiway to taxi following the heavy snowfall, odd smells and smoke were generated within the cabin, following these events, because the flame from rear of No.2 engine was continued, the flight crew conducted the Emergency Evacuation from the Aircraft. At the time, a passenger descended the slide, fell down to the ground from the hip of the passenger and suffered serious injury.

Regarding the occurrences of odd smells and smoke in the cabin and the continuation of the flame at the rear of No.2 engine, it is probable that the Heavy Snow became intense due to the rapid weather deterioration, and because the icing was set at fan blades and low pressure compressor, the engine oil was leaked into inside of the engine and the oil vaporized into the cabin and the leaked oil was accumulated within in the tailpipe to catch the fire.

The JTSB reported the aircraft was taxiing for departure when heavy snow fall started prompting the captain to taxi to an apron for de-icing. When the aircraft stopped on taxiway T2 when the visibility deteriorated to a point where the captain felt they could no longer safely identify the taxiway center line, odd smells and smoke appeared in the cabin, flames were observed from the #2 engine prompting the crew to initiate an emergency evacuation via slides through the left hand doors.

The JTSB analysed that the weather conditions with outside temperature as well as the dew point being -1 degrees C icing conditions were likely to exist when heavy snow fall began.

The JTSB analysed:

At the Aircraft investigation after the accident, as described in 2.8.2(1), it was confirmed that the icing were generated on fan blades and LPC of No.1 engine and No.2 engine of the Aircraft. Moreover, as described in 2.1.1, amounts of engine oil from both engines started to decrease at 14:56. It is probable that this decreases of engine oil amounts were caused by the leakage of the oil from inside of bearing sump to LPC, because the airpressure at outside of bearing sump seal could not be kept high due to the decreases of air inflow amount into engine by the icing on fan blades and LPC.

Furthermore, as described in 2.8.2 (2), traces of high temperature air flowing through inside of CVT from the rear to forward and soot and engine oil inside of air duct were confirmed. It is probable that these events were caused by the mixing with engine oil leaked from the bearing sump when the heated air from inside at rear of engine were sucked in and reversed from rear to front through the air duct and CVT described in 2.5.4, because the air inflow amount decreased from outside at front.

It is probable that because it is considered that the engine oil was leaked into LPC and as described in 2.8.2 (3), it is confirmed that the engine oil was attached to inside of the PACK duct, the engine oil leaked into LPC was mixing with the compressed air bled from HPC described in 2.5.2 and as via PRSOV and PACK it flew into the cabin in fog like condition, it generated the odd smells and it looked like smoke. Due to this, it is probable that when the flight crew shut off the PACK and recirculation fan as a temporary measure, due to the halt of the inflow of the mixed air with engine oil to the cabin, the odd smells and smoke were mitigated.

The JTSB analysed further that due to increasing icing caused a decrease of air being taken in by the engine until the fuel/air ratio in the combustion chamber became inappropriate causing the #2 engine to run down and stop.

After the #2 engine stopped a flight attendant observed a flame from the tail pipe of the #2 engine. The JTSB wrote: "Also, as described in 2.8.2 (2), as the accumulated oil was confirmed at the tailpipe, and the engine oil component was confirmed within the soot attached at the tailpipe. Based on these, it is probable that regarding the flame from the rear of the engine, as the part of leaked oil described in 3.4.1 was discharged via CVT into the tailpipe, because of the stop of the engine, the engine oil remained at inside of the tailpipe was ignited by its exposure to the heat of tailpipe."

The JTSB analysed that following the observation of the flame by the flight attendant the crew did not have a fire indication for the right hand engine and therefore did not discharge the fire extinguisher although the crew was working the engine severe damage or fire checklists and pulled the fire handle to shut the engine down. As the fire was fed by engine oil that had migrated to the tailpipe, the fire handle could not stop the fire. The flight attendant reported the flame was still visible which prompted the captain's decision to evacuate the aircraft.