Three years ago on this day, VH-FVN an ATR72-212 600 series (ATR72) was operating Virgin Australia Airlines flight VA660 from Sydney to Canberra in Australia. Onboard, 42 passengers, 2 cabin crew and 2 flight crew.
During flight preparation, the crew were aware of significant weather on route, whit a line of thunderstorms expected over Canberra at the time of their arrival.

VH-FVN climbing out of Sydney (14-01-2017 © Peter Reading)
After take-off (At approximately 17.41lt) the crew monitored the weather and made plans to avoid the storms. They had taken off with sufficient fuel for the flight to Canberra, a possible return to Sydney and 2 hours of holding.
10 minutes after departure the crew requested a diversion left of track of 5 miles was requested and granted. several more heading requests and altitude changes were requested and granted About 15 minutes after take-off ATC requested the crew to provide them with a heading to avoid the weather, which was provided and granted. The aircraft continued on its flight to Canberra with the crew continuously monitoring the weather. When getting closer to Canberra to the crew was cleared for a BUNGO 3A STAR. En route to the STAR the aircraft entered visual moisture with the TAT below 7º C, in accordance with the FCOM (Flight Crew Operating Manual) the crew turned on the anti-icing systems, as these conditions were considered as icing conditions.
After spending 7 minutes in holding the crew requested and was given a southerly heading to avoid weather, followed by a turn towards the North to head back toward Canberra. The arrival was changed to a POLLI 7 STAR, The crew entered a hold over POLLI and at 1853lt they were cleared to descend to 9000 ft and commence the STAR.

The radar image fro 18.54lt with the flight path overlay and the flameouts indicated (Source and © https://www.atsb.gov.au/).
While descending for 9000 feet shortly after passing FL110, with both throttles close to idle, at approximately 1854lt the Master Warning lights came on and the ENG 2 OUT was annunciated. The engine #2 torque was indicating zero. In the time it took the crew to confirm an Engine #2 Out condition and acknowledge the warning the engine recovered and returned to normal indication and operation. All warnings were extinguished.
Just over a minute later, with the power levers now at idle, the ENG 1 OUT annunciators came on together with the Master Warning lights, with the engine #1 torque indicating zero. Identical to Engine #2 self-recovery, also Engine #1 self recovered before the crew could initiate any checklist. Ignition was selected to Manual by the crew in order to keep ignition on continuously to (hopefully) prevent further flameouts. There was no procedure or checklist requiring the crew to do this, they did it out of an abundance of caution.
With both engines operating normal, the crew discussed the situation but were unable to determine the cause of the flameouts. They confirmed the De-icing and Anti-icing systems were set correctly for flight in icing conditions. When they observed the TAT at 12 degrees they elected not to switch the De-icing and Anti-icing systems off and continue to fly the aircraft at icing speeds.
{Icing speeds are minimum manoeuvre speeds in icing conditions that must be flown in order to provide sufficient margin against aerodynamic stall}
The approach was continued and at 1901lt the crew confirmed they were no longer in icing conditions and selected the (airframe) De-icing to off while keeping the (engine) Anti-icing systems on.
The engines operated without remarks for the remainder of the flight and the craft landed at Canberra at 19.06lt

FDR Data from the flame-outs (© https://www.atsb.gov.au/)
Subsequent maintenance investigations found no indication of system failures.
The incident was also investigated by the ATSB (Australian Transport Safety Bureau). They concluded that the most probable cause for the flameouts were environmental conditions and that the automatic relight function had worked as designed on both engines.
The full report ATSB report can be found by clicking here
The aircraft resumed normal operations afterwards without further engine problems.
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