VNA 320 NEO Dual Flameout Danang
 

Does anyone have insight into this incident?
it happened a couple of days ago descending into Danang with PW engines.

Didn't VietJet have a similar issue in Danang?

If the event aircraft is flying again the next day in revenue service, I seriously doubt it was a dual engine power loss event, particularly if they didn't find a cause...

Ask Sully!

Covered in Aviation Herald here Incident: Vietnam A21N near Haiphong on Jul 2nd 2019, both engines briefly did not respond to thrust commands
"both engines briefly did not respond to thrust commands ... the fault cleared by itself"

fault cleared by itself? Excellent! no problem here.

A similar situation occurred to a Jetstar 787 into Osaka a couple of months ago. Both engines indicated eng fail on EICAS but then auto recovered. I get the feeling that the engine manufacturers are walking a similar path to Boeing and the 737 Max. The line pilots are becoming test pilots because the corporations don't want to spend a lot of money on flight testing. Bring ETOPS approvals back to 180 minutes and see how quickly things get fixed.

To be fair, I don't believe that aircraft was back in service the next day...

True, but what if it had occurred into Cairns? I think that its extended stay on the ground had more to do with the national authority than the manufacturer's insistence.

Sounds like you have a pretty low opinion of your national authority. Not sure that it's justified.
From time to time we'd get a query from an operator that had experienced something really unusual, and wanted to know if they could continue operating or if they needed to take the aircraft out of service to investigate. More often than not when we looked at the data, the aircraft was operating as designed - but occasionally they were told to ground the aircraft to investigate.
Then again, there was a case back around 2005 when a 767 experienced a dual engine flameout on descent due to Ice Crystal Icing (US Operator into someplace in Mexico), - but the crew didn't even notice. They'd squawked a main bus power anomoly (both generators had dropped when the engines went below 50% N2) that self corrected (the engines relit without crew action or knowledge). We got a data recorder download to investigate the power problem and quickly realized the problem wasn't main bus power, it was that the engines weren't running...

Thanks for the chuckle. Reminds me of doing a walk-around and one tire pressure is low. Contact maintenance and they check - "we found out why the tire is low - two bolts are missing." Sometimes the answer is simple.

I have the same opinion of our national regulator.

There was a rumour the same aircraft recently had the same or similar event - then ferried back to either Melbourne or Sydney same or next day.

Did we ever hear the reason this same aircraft after the Osaka event went to Hong Kong?

There is a big difference between a non-revenue ferry flight back to a maintenance base so it can be properly investigated, and returning to revenue service the next day.
As for the cause, I've not seen anything but I've been out of the loop since I retired.

The question is who sign's off on a "double engine failure" flight permit and what conditions, inspections/test are required before such flight?

No risk in double failure or even roll back around either Melbourne or Sydney to anyone other than crew.

I can see the Flight Permit now - both crew must watch "Miracle on the Hudson" immediately prior to flight.

Well, by your own admission, it's a rumor, not fact. I've found that rumors - even when based on fact - usually leave out or alter significant details of the actual fact (particularly when someone has an agenda).
So, even it it did happen, you have zero information on what inspections and checks they might have made prior to the decision to ferry the aircraft to a maintenance base and what communication may have taken place between the operator and the manufacturers prior to the ferry flight.

I did check the flight tracker of that day and the aircraft did not go to it's planned destination but did go to either Melbourne or Sydney instead, but correct I have nothing but the rumour of why.

In Australia God is CAsA and Major Defects must be reported, I do not recall the exact wording but this type of incident certainly would need reporting to CAsA.

The decision to then fly the aircraft is not up to the operator or the manufacturer but CAsA or a person they delegate (this could be a Qantas employee). A delegate would need to be able to satisfy the reasons for issuing a Special Flight Permit to CAsA that would be very hard to do given the previous history in Osaka.

That said CAsA seem to allow a certain amount of "self regulation" by a certain operator. The FAA recently have some credibility issues by some around the globe, CAsA have long had that issue within Australia for years. Most would agree if a certain Australian airline had a fleet of MAX aircraft the Australian Regulator would only have grounded them after the FAA.

quote
" when both engines (PW1130G) became unresponsive to thrust commands and thrust levers for some time, the fault cleared by itself "
unquote

Sounds like the engines were still running but didn't respond to TL command.

Agreed, but a simultaneous dual engine Loss Of Thrust Control (LOTC) is still quite worrisome - had it happened close to the ground it could easily have had an unhappy ending. Remember, a dual engine LOTC was the cause of the BA 38 777 crash at Heathrow - and had it not resulted in a crash, as soon as the fuel warmed up a bit the ice and faults would have cleared and left zero evidence.