LATAM 787-9 sudden drop in cruise

[violator]

https://www.nzherald.co.nz/nz/latam-flight-from-sydney-to-auckland-nose-dives-passengers-and-crew-thrown-into-ceiling/MBE4BNFIFJD73DDZJ3USYZYL5M/

Seems like a significant event, not linked to turbulence. Jokat said the pilot came to the back of the plane once the plane landed.

“I asked him ‘what happened?’ and he said to me ‘I lost my instrumentation briefly and then it just came back all of a sudden’.

[RickNRoll]

A passenger two seats away from him was not wearing his seatbelt, and flew up and hit the ceiling, Jokat said.

“I thought I was dreaming. I opened my eyes and he was on the roof of the plane on his back, looking down on me. It was like The Exorcist.”


They also say it went into a "nosedive".

[Obba]

I'm not sure if i have the right flight!

Is 4000ft descent a lot..?

https://i.imgur.com/gPW3SXb.jpg

Mods please delete if I am incorrect.

[Sunnyjohn]

I have a feeling I've read of similar situations over this part of Australia and there was a suggestion that high magnetic fields produced by the iron mines were affecting the controls. Anyone remember?

[Rick01]

Over the Tasman Sea? Is that even 'part of Australia'??

[Lookleft]

Yes i do remember and it had nothing to do with high magnetic fields produced by iron mines. The two incidents you are referring to were both investigated by the ATSB and there was no evidence of external influences on the aircraft. The LATAM incident was over the Tasman Sea close to NZ where there are no iron ore deposits or US military facilities so what exactly is your point?

[helispotter]

I have a feeling I've read of similar situations over this part of Australia... Anyone remember?

You may be thinking of the incident involving the
In-flight upset of QANTAS Airbus A330-303, VH-QPA, 154 km west of Learmonth, WA, 7 October 2008? ATSB report at:

https://www.atsb.gov.au/publications/investigation_reports/2008/aair/ao-2008-070

Location very different and report indicates cause was equipment generating spurious output.

Description of this 787 incident so far seems quite different.

[Cloudee]

From the ABC (Australian Media)

https://www.abc.net.au/news/2024-03-12/latam-airlines-working-with-authorities-to-investigate-fault-/103575616
In an interview with the ABC, Mr Jokat said he spoke to the pilot once they were on the ground in Auckland.

"When we landed, the medics were on board instantly and people were clapping and joyous … and people were still wincing in pain and there was a lot of groaning going on," he said.

"The pilot actually showed up at the back of plane kind of wanting to see with his own eyes what had transpired and I approached him and said, 'What was that?'

"He said, 'I lost control of the plane. The gauges went blank for a second.' And then he said they came back on miraculously and the plane just righted itself on its own."

[megan]

Over the Tasman Sea? Is that even 'part of Australia'?Well, NZ was once part of Australia, New South Wales to be exact, so I guess yes is the answer. :p

https://www.nma.gov.au/defining-moments/resources/new-zealand-becomes-a-separate-colony

One comforting thought is when pilotless cockpits come about. (Facetious comment)

[artee]

One comforting thought is when pilotless cockpits come about. (Facetious comment)

At that point, in case of emergency, small keyboards will descend, like oxygen masks, with Ctrl-Alt-Del keys...

[ivorget]

Somone on reddit posted about this old Dreamliner issue which sounds at least vaguely similar to what the the pilot reported in Cloudee's comment above.
They also said there's been no notice from Boeing that the issue was ever fixed. Maybe some 787 pilots can confirm?

From 2016:
www.seattletimes.com/business/boeing-aerospace/faa-orders-787-safety-fix-reboot-power-once-in-a-while/

[krismiler]

Sudden loss of power and everything goes slack, power comes back on and the aircraft suddenly decides to right itself leading to a violent manoeuvre.

[MechEngr]

Industry wide problem. https://www.reddit.com/r/technology/comments/chomds/airbus_a350_software_bug_forces_airlines_to_turn/ 190 hours instead of 22 days.

[Matt48]

Industry wide problem. https://www.reddit.com/r/technology/comments/chomds/airbus_a350_software_bug_forces_airlines_to_turn/ 190 hours instead of 22 days.

Just like a dodgy old printer.

[RickNRoll]

Industry wide problem. https://www.reddit.com/r/technology/comments/chomds/airbus_a350_software_bug_forces_airlines_to_turn/ 190 hours instead of 22 days.
That's four years ago. Wouldn't there be a patch for that on the A350 by now.

[mahogany bob]

What on earth happened in this amazing/worrying incident !
Should ALL B787s be grounded until answers ( and solutions ) are provided by Boeing ??

BEFORE SPECULATION runs rife!

Eg 2016

The FAA is mandating that operators of Boeing’s 787 Dreamliner periodically reset the power on the airplane to avoid a glitch that could cause all three computer modules that manage the jet’s flight control surfaces to briefly stop working while in flight.

???

PS presumably if this had happened at low level the ac would have crashed?

[MechEngr]

Were airlines appropriately cautious they would park them for a few days while the initial readback of the FDR and CVRs was done. They should not wait for a government order to do so.

I see there was also another time problem / counter rollover identified on 787 that fits the symptoms very well:

"More trouble for Dreamliner as Federal Aviation Administration warns glitch in control unit causes generators to shut down if left powered on for 248 days"

"The US air safety authority has issued a warning and maintenance order over a software bug that causes a complete electric shutdown of Boeing’s 787 and potentially “loss of control” of the aircraft.

In the latest of a long line of problems plaguing Boeing’s 787 Dreamliner, which saw the company’s fleet grounded over battery issues and concerns raised over possible hacking vulnerabilities, the new software bug was found in plane’s generator-control units.

The plane’s electrical generators fall into a failsafe mode if kept continuously powered on for 248 days. The 787 has four such main generator-control units that, if powered on at the same time, could fail simultaneously and cause a complete electrical shutdown.

We are issuing this AD [airworthiness directive] to prevent loss of all AC electrical power, which could result in loss of control of the aeroplane,” said the Federal Aviation Administration directive. “If the four main generator control units (associated with the engine-mounted generators) were powered up at the same time, after 248 days of continuous power, all four GCUs will go into failsafe mode at the same time, resulting in a loss of all AC electrical power regardless of flight phase.”

https://www.theguardian.com/business/2015/may/01/us-aviation-authority-boeing-787-dreamliner-bug-could-cause-loss-of-control

Per the AD:

​​​​​​​We have been advised by Boeing of an issue identified during laboratory testing.
The software counter internal to the generator control units (GCUs) will overflow after
248 days of continuous power, causing that GCU to go into failsafe mode. If the four
main GCUs (associated with the engine mounted generators) were powered up at the
same time, after 248 days of continuous power, all four GCUs will go into failsafe mode
at the same time, resulting in a loss of all AC electrical power regardless of flight phase.

https://s3.amazonaws.com/public-inspection.federalregister.gov/2015-10066.pdf

This is superseded by AD 2018-20-15 to install new software. See https://ad.easa.europa.eu/ad/US-2018-20-15 et al.

​​​​​​​SUMMARY: We are superseding Airworthiness Directive (AD) 2015-09-07, which applied to all
The Boeing Company Model 787 airplanes. AD 2015-09-07 required a repetitive maintenance task
for electrical power deactivation. This AD requires installing new software for the generator control
unit (GCU). This AD also removes certain airplanes from the applicability. This AD was prompted
by the determination that a Model 787 airplane that has been powered continuously for 248 days can
lose all alternating current (AC) electrical power due to the GCUs simultaneously going into failsafe
mode. We are issuing this AD to address the unsafe condition on these products.

The 22 day version refers to a similar counter bug in the computers for flight controls.

[msbbarratt]

If it is a reoccurence of the old value overflow bug, it then becomes interesting to know the service history of this aircraft!

If that problem is still being addressed by "switch it off and then on again", that sounds exactly like the kind of problem that shouldn't be allowed to exist. It'd be in the same category as the MAX anti-ice issue - a note to pilots is not enough. I'm not certain of the current status of that issue, but I really hope it has been fully addressed.

[MechEngr]

If it is a reoccurence of the old value overflow bug, it then becomes interesting to know the service history of this aircraft!

If that problem is still being addressed by "switch it off and then on again", that sounds exactly like the kind of problem that shouldn't be allowed to exist. It'd be in the same category as the MAX anti-ice issue - a note to pilots is not enough. I'm not certain of the current status of that issue, but I really hope it has been fully addressed.

The bug has been addressed by the new software, but it requires the operator to install the new software. This is a Chilean aircraft, so it's up to them to keep up, and they have had 5-6 years to do so. This time interval wasn't something for the pilots to manage but for the maintainers.

[dixi188]

How is it "FAILSAFE" if all the generators shut down together?

[krismiler]

https://www.aviationtoday.com/2015/05/05/boeing-787-power-issue-to-receive-software-fix/


Avionics Today 05-05-2015] Boeing will provide a software update later this year to address an issue that causes the 787 Dreamliner’s Generator Control Units (GCUs) to simultaneously go into failsafe mode after being powered continuously for 248 days. The FAA has issued an Airworthiness Directive (AD) calling for 787 operators to address the glitch, which is caused by a software counter internal to the GCUs that will overflow after 248 days of continuous power, the AD states.

https://www.aviationtoday.com/wp-content/uploads/2015/05/Boeing20787209.jpg

Boeing 787-9 Dreamliner. Photo: Boeing

According to the FAA’s directive, when a 787 has been powered continuously for 248 days, it can lose all Alternating Current (AC) electrical power due to the GCU software anomaly. The directive requires a repetitive maintenance task for electrical power deactivation on 787s.

“This condition is caused by a software counter internal to the GCUs that will overflow after 248 days of continuous power. We are issuing this AD to prevent loss of all AC electrical power, which could result in loss of control of the airplane,” the FAA’s directive states.

Boeing plans on issuing a software update for the 787 by the fourth quarter of 2015 to address the issue.

Originally, Boeing observed this GCU software issue during lab testing after eight months of continuous power. After discovering the issue, Boeing recommended the AD’s mandated actions to operators on April 19, 2015.

“It is important to note this issue was observed in the lab only after eight months of continuous power, which would be highly unusual. All operators have already completed the cycle off-cycle on fix, and they know how often they need to do it in the future until the software update arrives later this year,” a spokesman for Boeing told Avionics Magazine.

Most importantly, the AD addresses an anomaly that would only occur under extremely rare conditions within normal airline fleet schedules. By performing a power-off/power-on cycle, operators eliminate the risk that all six generators aboard the aircraft would lose power at the same time.

In the directive, the FAA indicates that in the occurrence that the four main GCUs associated with the engine mounted generators were powered up at the same time, the four GCUs would all fail at the same time. This would result in a “loss of all AC electrical power regardless of flight phase,” the AD states.

Boeing 787 fleet maintenance records indicate that all in-service airplanes have already performed a power-off/power-on cycle within their ongoing maintenance schedules. Operators that have a definitive record of a power cycle within the last 120 days do not need to take any immediate action, Boeing has confirmed. A total of 28 aircraft in the U.S. registry are affected by the AD, which has also determined that the cost of the electrical power deactivation is one work hour at $85 per deactivation cycle.
Since it first entered service in 2011, Boeing has delivered 258 total 787s, and has a backlog of 847 undelivered Dreamliners.

[OldnGrounded]

How is it "FAILSAFE" if all the generators shut down together?

It isn't, obviously, but (a) the risk event probability of all four GCUs shutting down generators simultaneously will certainly have been calculated as vanishingly low and (b) no one anticipated that any GCU would shut down because the firmware had a glitch like this baked in.

Edit: Also, if this is what occurred on the subject LATAM flight, surely it will have been the first time ever to have occurred in the wild (the sky). And it seems to me that would be vanishingly unlikely. The maintainers would have had to fail to perform the firmware/software update and the aircraft would have to have been powered up for 248 days. I don't gamble but I'd bet against that.

[Sunnyjohn]

"…so what exactly is your point?"
Sorry - I don't understand. I thought my post was perfectly clear.

[FairlieFlyer]

Fat ass sitting on controls sounds possible too

[Ikijibiki]

There's a much more informative thread on this subject in Australia, New Zealand & the Pacific (https://www.pprune.org/australia-new-zealand-pacific-90/).

[Thirsty]

I have a feeling I've read of similar situations over this part of Australia and there was a suggestion that high magnetic fields produced by the iron mines were affecting the controls. Anyone remember?

SunnyJohn: At first I though it might be April 1st, and you were taking the mickey out of us, but I see you are from Spain so will pity and have a laugh with you, and maybe have a shout for you at the local pub. You've been roundly pranked, a common habit of those downunder who wax long about dropbears, and kangaroos strolling down the main thoroughfare of George St, Sydney with foreigners.

Check your atlas: Flights to New Zealand usually head EAST over water from Australia, and not lumps of magnetic ore that make the compass spin wildly like in the Bermuda Triangle.

You will also note the aircraft was significantly closer to New Zealand than SunnyOz, and the New Zealanders also have a somewhat warped sense of humor and a streak of larrikanism as well.,

Here's a deviant suggestion: We are nearing the peak of the 10 year sunspot cycle. Unless you can pinpoint sunspot activity as directly affecting the aircraft at that particular time and date, I strongly suspect whatever the problem was, it was NOT external and NOT location based,and was confined to that one aircraft. Conspirators in this thread are welcome to prove me wrong.

[601]

Don't be too hasty in saying that it is a long way from WA and ore deposits.
Ironsand occurs extensively on the west coast of New Zealand's North Island. The sand makes up a large portion of the black-sand beaches on the North Island, as well as the surrounding sea floor. The magnetite in the sand contains fairly large quantities of titanium, and is sometimes referred to as titanomagnetite.
powered up for 248 days
Doesn't anyone shut down the aircraft, lock it up and take the keys home anymore?

[msbbarratt]

The bug has been addressed by the new software, but it requires the operator to install the new software. This is a Chilean aircraft, so it's up to them to keep up, and they have had 5-6 years to do so. This time interval wasn't something for the pilots to manage but for the maintainers.

Thanks MechEngr. I was thinking that the initial problem was some considerable years ago, plenty of time for a fix to have been developed.

I suspect that the report into this event is going to be uncomfortable reading for someone or other.

One thing does occur though. If the fix has been available for 5, 6 years and hadn't been installed, there's been enough time for this behaviour to have occured 7 or 8 times by now if the aircraft hadn't been routinely de-powered in all that time.

[aisleplease]

It isn't, obviously, but (a) the risk event probability of all four GCUs shutting down generators simultaneously will certainly have been calculated as vanishingly low and (b) no one anticipated that any GCU would shut down because the firmware had a glitch like this baked in.

Edit: Also, if this is what occurred on the subject LATAM flight, surely it will have been the first time ever to have occurred in the wild (the sky). And it seems to me that would be vanishingly unlikely. The maintainers would have had to fail to perform the firmware/software update and the aircraft would have to have been powered up for 248 days. I don't gamble but I'd bet against that.

Exactly! It almost didn't happen at all.

[jimjim1]

248 days. This reminded me of something I came across in the late 1990s. A particular piece of networking equipment that we had deployed on various customer sites died periodically. From memory it was not 248 days, but memory plays tricks.

The problem occurred at 2^31 hundredths of a second after power up. Well guess what?

2^31 hundredths of a second is indeed 248 days. The time was stored in a 32 bit signed integer, one bit used for the sign and the other 31 bits for the value. After about 248 days there is a risk of an arithmetic overflow and unpredictable software behaviour.

Looks like pretty poor testing for an aviation product.

[shinz0]

New Zealanders also have a somewhat warped sense of humor and a streak of larrikinism as well.,

Hoi, we resemble that remark though its what we tend to see as an Australian trait rather than ours quite so much. ;):)

[Senior Pilot]

Discussion here (https://www.pprune.org/australia-new-zealand-pacific/658090-latam-upset-syd-akl-mon-11-mar.html) with many duplicate posts, so this thread is now closed 👍