United 777 "dives" after takeoff from OGG [Archive]

Clandestino

13th Feb 2023, 07:26

Dang! It was a Boeing flown by US major with pilots having 25 Khrs combined so we cannot went our very strong feel... I mean: opin... I wanted to say: facts about how Airbus, everyone except the whi... I mean: first world aviators and youn... actually: inexperienced are just a menace to aviation. We can't rant about the weather either, lest we be mistaken as deluded non-thinking fools believing that global warming is real and not just what global conspiracy of lizard-people wants us to believe.

Provided FR24 data are reliable (which they have proven to be more often than not), that must've been a heckuwa rollercoaster ride. Were there any reports of "Scared passenger: we all thought we're gonna die!" in any of the local rags?

Chiefttp

13th Feb 2023, 12:32

From another website,,

A message from a friend:
Gusty takeoff, heavy rain, heavy plane, short runway, and at night. Used flaps 20.
At accel height, CA (PF) called for flaps 5. FO went through the gate and selected flaps 1. When climb rate dissipated, CA looked over to see the lever and unknowingly banked over as well. CA became disoriented and neither pilot noticed the dive until the GPWS warning. 2.7Gs at 775’ AGL to recover.

atakacs

13th Feb 2023, 12:44

2.7Gs at 775’ AGL to recover.
avorite expletive

At least is was apparently reported to the company :ok:

tubby linton

13th Feb 2023, 15:56

According to Flight Radar the incident occurred at 1449 local time so daylight and there were no gusts reported in the metar.

ethicalconundrum

13th Feb 2023, 17:49

Pilots 'received additional training'.

Ya think? >8000 FPM dive, waited to hear the GPW to recover, within 800' from the water. Finally, advanced technology saves one.

DaveReidUK

13th Feb 2023, 19:02

CA looked over to see the lever and unknowingly banked over as well.

There's no appreciable variation in the track during the event, suggesting that there can't have been much in the way of a bank for any length of time.

at 775’ AGL to recover.

The height quoted by FR24 is uncorrected for QNH - the actual minimum height would appear to have been around 150' lower than that.

Ollie Onion

13th Feb 2023, 19:44

2.75g, Jesus Christ, outside of the G Limits for any Passenger Jet and it continued to SFO?

B-757

13th Feb 2023, 19:47

.. 8000+fpm descend from 2200ft and recover by 800ft..?? Impossible in a B777. . Any pilot could tell that something doesn’t add up here..

Fly safe,
B-757

DaveReidUK

13th Feb 2023, 21:32

.. 8000+fpm descend from 2200ft and recover by 800ft..?? Impossible in a B777. . Any pilot could tell that something doesn’t add up here.

Vertical rate (RoD/RoC) is a second-order ADS-B parameter and should be treated with caution in any regime other than a uniform climb/descent.

That said, the elapsed time for the upset from 2200 feet, down to 775 feet and back to 2200 was approximately 28 seconds, so unless doubt is being cast on the instantaneous height values or timestamps, that does indeed appear to be what happened.

WillFlyForCheese

13th Feb 2023, 21:58

Haven’t seen much about this. United flight 1722 from OGG to SFO experienced a significant drop in altitude after taking off from Maui on December 18. Heavy rain at that time - pilots recovered about 800 feet over the water - then proceeded to SFO. Must have been quite a ride.

More here:

https://theaircurrent.com/aviation-safety/united-maui-dive-ua1722-close-call/

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/2000x1111/ab9c7209_6e97_41f7_939f_00fb3ac16636_439668497f26f94f7a2613a 1a9a6d9e2513eb535.jpeg

Skyray

13th Feb 2023, 22:05

I was reading the article and was surprised at how reasonable and informed the writing was. Then I saw it was Jon Ostrower; he knows his stuff and doesn't sensationalize.
2.7Gs in a 777 had to be exciting. Weather was bad -- windshear?

GlobalNav

13th Feb 2023, 23:53

Why wasn't this reported on Dec 18 and why did the crew continue to SFO? What does the NTSB say?

Seat4A

14th Feb 2023, 03:21

For those interested, Juan's comments

https://www.youtube.com/watch?v=1B9mQQnZg_8

This comment was posted below the video.

QUOTE:
jdorenbecher

Former pilot and I was on that flight on that day. Shortly after TO the pilot slightly retarded the engines. I noticed it but it was subtle. Then we started sinking. The aircraft did not nose over into a dive. It felt like we were hit with a downdraft. Many screamed and the crew increased thrust and recovered and climbed up to FL39 and smooth air. I normally don't get too bothered by turbulence but I knew we were very close to the water having only been in the air for slightly more than a minute.

Propellerhead

14th Feb 2023, 07:39

Does Maui have non standard AA? Should be clean well before 2200ft. And selecting flap 1 instead of 5 might not even be noticeable - you’re accelerating anyway. In that weather why not use the autopilot?? Also, not unreasonable to continue the flight to destination. What advantage is there of doing a diversion back to bad weather and maybe even having to dump fuel?

AerocatS2A

14th Feb 2023, 08:22

anxiao

14th Feb 2023, 08:25

I note that the Jon Ostrower account states that the aircraft arrived in SFO, did a two and a half hour turnaround and then departed to ORD. I have not read the MM for a triple but I would have thought that a 2.7g positive would have required more than a 2.5 hour inspection.

Reminds me of the cartoon of a ground engineer climbing over a farm fence into a field in which two pilots sit amongst a yard sale of smoking aircraft parts and shouts to them, "Don't put it in the book, it's due out in an hour"

DaveReidUK

14th Feb 2023, 08:35

I note that the Jon Ostrower account states that the aircraft arrived in SFO, did a two and a half hour turnaround and then departed to ORD. I have not read the MM for a triple but I would have thought that a 2.7g positive would have required more than a 2.5 hour inspection.

I'd be interested to see the back of the envelope with the "2.7g" calculation, given that we know it didn't come from the FDR.

I'm not saying it's wrong, I'd just like to see the maths.

spornrad

14th Feb 2023, 09:12

Well, the math for the vertical acceleration is simple: -8600 to +8600 fpm (diff = 94 m/s) in (13 s) squared needs appr. 0.6 g, + earth pull makes 1.6 g vertical ballpark. This is of course only a very rough avg. estimate because vert. speeds are secondary data derived from diff between individual ADSB altitude transmissions, therefore peak acceleration could be significantly more.

DaveReidUK

14th Feb 2023, 13:56

After a bit of pencil-sharpening, and subject to the aforementioned caveats about instantaneous vertical rates, a bit of smoothing produces an average vertical acceleration of 2.77g over the 7.2 seconds between 1050' on the way down and 1025' on the way up, so pretty close to the estimate from the unidentified analysts mentioned in the original link.

Ppaul3

14th Feb 2023, 16:16

The AViation Herald take on the incident….”From my editorial point of view it is clear however, that the occurrence did not happen along the lines of the report that surfaced on Sunday.”

Chgoquad

14th Feb 2023, 16:16

Just saw this in the NY Post. Scariest part about it might be that the pilots were both so experienced...

BFSGrad

14th Feb 2023, 16:22

I'd be interested to see the back of the envelope with the "2.7g" calculation, given that we know it didn't come from the FDR.
How do we know that the g figure didn't come from the FDR? I'm including FOQA/FDM/QAR data as equivalent to FDR.

pattern_is_full

14th Feb 2023, 17:23

Classic microburst - fortunately with enough altitude to recover.

DaveReidUK

14th Feb 2023, 18:16

How do we know that the g figure didn't come from the FDR? I'm including FOQA/FDM/QAR data as equivalent to FDR.

Well I inferred that from the comment in the link from post #12.

But you're right, I could be wrong and those "people familiar with the incident" might be basing their comment on FDR data.

In that case, I'm going to have to try extra hard not to feel smug about the figure I calculated. :O

tubby linton

14th Feb 2023, 18:35

The Rate of Descent achieved is very close to that of AF447 when it was stalled. The published fact that both pilots have been retrained suggest that a stall occurred rather than Mother Nature interfering.

BoeingDriver99

14th Feb 2023, 19:20

Why would you keep quiet about a microburst? :8

WillFlyForCheese

14th Feb 2023, 19:52

Here is one passenger's account of what happened - it is certainly described as a "nose down" event. Stall recovery?

"Rod Williams II said he was sitting near the back of United Flight 1722 with his wife and kids on December 18 when it suddenly came down. The plane, which had been headed to San Francisco from Hawaii when it found itself in an intense storm, proceeded to go into a 'dramatic, nose-down' dive for about eight to 10 seconds, creating mass pandemonium in the cabin, Williams said."

"About ten minutes later, and there was an announcement that assured the passengers the event had passed. "Someone from the cockpit got on the intercom and said, 'Alright, folks, you probably felt a couple G's on that one, but everything's gonna be OK,' said Williams, who is the first passenger to provide a personal account of the incident. ''We're gonna be alright,'' Williams credited the United staffer saying."

https://www.dailymail.co.uk/news/article-11746913/Passenger-onboard-United-Airlines-flight-nose-dived-1-400ft-describes-ordeal.html

judyjudy

14th Feb 2023, 20:07

Wouldn’t there be some buffeting just before a stall? Just SLF here looking to be enlightened.

DaveReidUK

14th Feb 2023, 21:16

proceeded to go into a 'dramatic, nose-down' dive for about eight to 10 seconds, creating mass pandemonium in the cabin

The data suggests the FPA was around -15°.

Seat4A

14th Feb 2023, 22:08

Why wasn't this reported on Dec 18 and why did the crew continue to SFO? What does the NTSB say?

https://twitter.com/NTSB_Newsroom/status/1625597311060418571?cxt=HHwWloCxmYiJpI8tAAAA

BFSGrad

14th Feb 2023, 22:18

My read of Part 830 is that this event does not meet the definition of “serious incident.” Therefore, no reporting is required to NTSB unless NTSB initiates the request. Appears today’s Tweet documents such a request.

DaveReidUK

14th Feb 2023, 22:40

My read of Part 830 is that this event does not meet the definition of “serious incident.”

That's correct. Although the event certainly falls within the Annex 13 definition of a Serious Incident.

Annex 13 even provides, as an example of an event that would be so classified, "Controlled flight into terrain only marginally avoided".

bean

15th Feb 2023, 02:13

Classic microburst - fortunately with enough altitude to recover.
Read previous comments. Cause is known

Klauss

15th Feb 2023, 04:03

Read previous comments. Cause is known

Hi, how about a date-and time check ?
Just 4 hours before this incident, HA 35 had the severe turbulence that injured many.

Both cases are weather related, I´d say.

bean

15th Feb 2023, 11:11

Hi, how about a date-and time check ?
Just 4 hours before this incident, HA 35 had the severe turbulence that injured many.

Both cases are weather related, I´d say.
NO. NOT AT ALL

ojguilty

15th Feb 2023, 12:12

Dang! It was a Boeing flown by US major with pilots having 25 Khrs combined so we cannot went our very strong feel... I mean: opin... I wanted to say: facts about how Airbus, everyone except the whi... I mean: first world aviators and youn... actually: inexperienced are just a menace to aviation. We can't rant about the weather either, lest we be mistaken as deluded non-thinking fools believing that global warming is real and not just what global conspiracy of lizard-people wants us to believe.

Nice job bringing race into a discussion where it clearly doesn't belong. The Captain of this flight actually was not "whi", as you say, but the investigation will fortunately proceed without no attention paid to that.
They don't call it global warming any more, btw. Because it's hasn't been warming for awhile now. They call it climate change.

Fewdoom

15th Feb 2023, 14:04

Another unreported near-CFIT
It was reported immediately after landing through the proper channels.

FlightDetent

15th Feb 2023, 14:44

... bringing race into a discussion ... and many other typical prejudices that build a certain very ugly but well-known narrative.

Lost on you in the translation is the posted sarcasm, mocking that very mindset you cannot unsee and neither do we. All on the same team, peace.

</drift>

DaveReidUK

15th Feb 2023, 15:14

Avherald mantains it didn't happen as reported:

"In addition, if indeed 2.7G were encountered, passengers would certainly have reacted and this occurrence would have been all over the media the next day at the very latest. If the FDR indeed had recorded 2.7G, then the aircraft could not have flown within 2.5 hours after landing due to the mandatory structural inspection."

"From my editorial point of view it is clear however, that the occurrence did not happen along the lines of the report that surfaced on Sunday."

Bizarrely, the argument that it didn't happen is justified by citing the FlightAware ADS-B log, despite the fact that it contains no data points at all during the 25 seconds of the roller-coaster.

Incident: United B772 at Kahului on Dec 18th 2022, pilots filed safety report (http://avherald.com/h?comment=50526a09)

WillFlyForCheese

15th Feb 2023, 16:20

Avherald mantains it didn't happen as reported:

Bizarrely, the argument that it didn't happen is justified by citing the FlightAware ADS-B log, despite the fact that it contains no data points at all during the 25 seconds of the roller-coaster.

Incident: United B772 at Kahului on Dec 18th 2022, pilots filed safety report (http://avherald.com/h?comment=50526a09)

Saw that - but Simon's position is inconsistent with the little bit we do actually (think we) know - including the first hand statements from a passenger about what he (they) sensed on board. The reality is, and facts are, that something happened shortly after takeoff - sufficient that the pilots reported it and were given extra "training". The passengers certainly noticed something was amiss too. Maybe it's not 2.7G - but something happened.

DaveReidUK

15th Feb 2023, 16:26

Original FR24 plot (green) plus all of FlightAware's data points (blue), the latter cited by Avherald as "evidence" it was a non-event:

https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/1293x1156/ua1722_plus_flightaware_plots_0752d39278ef20231d2140751796cf d626454df7.jpg

That will save the NTSB a lot of work. :ugh:

FlightDetent

15th Feb 2023, 16:39

to consider:

pax with piloting background saying it did not feel like a nose-dive or push-over is actually consistent with a banked loss of altitude on a steady positive g. One of the reasons it might go unnoticed by the pilots in the first place. Someone sitting in another location of the humongous cabin might get a markedly different perception.

Noted, the tracked open data do not seem to show the expected heading divergence.

Ceterum censeo CVR...

RatherBeFlying

15th Feb 2023, 17:44

Notacommercialpilot

15th Feb 2023, 21:44

A microburst can certainly upset the flight path without warning, and there is a tendency to blame the crew for mishandling until the data is analyzed - been there.

There are a plethora of data sources flying about. What will count is the fdr or QAR, especially since they offer sub second resolution.

Assuming they kept those records...

I guess I am thinking this really happened. It sounds like the captain coming on the PA and saying "you might have felt a couple of Gs" is indication that there was indeed a steep descent and immediate ascent. I also suspect that he didn't pick that number randomly and likely lowballed it (natural human tendency in a situation like this). The fact that this statement was made along with the FR24 data, and the pilots receiving retraining makes me fairly certain that what has been floated (incorrect flap retraction / loss of lift / recovery) is the most likely scenario. I am curious whether UA preserved the FDR data and/or CVR data.

FlightDetent

16th Feb 2023, 05:07

Ikijibiki

16th Feb 2023, 17:11

Passenger Roid Williams recounts the episode to the Washington Post:

Boarding and taxiing went smoothly, he said. The pilots squared the Boeing 777 with the runway, hit the throttle, accelerated down the airstrip and took off. For about a minute, they climbed normally.

Then, the nose pitched up and the plane started ascending at “an alarming angle,” Williams wrote in a Facebook post recounting the incident.

“That’s when you started to hear folks let out a few screams,” he told The Post.

Williams, who studied aviation, said he feared the plane might stall. After climbing steeply for three to five seconds, the plane went into a sudden nosedive.
. . .
After diving for nearly 20 seconds, the plane pulled up “at a very strong rate.” Williams clenched his teeth, squeezed his armrests, pushed himself into the back of his seat and kept muttering prayers.

DaveReidUK

16th Feb 2023, 18:18

Then, the nose pitched up and the plane started ascending at “an alarming angle,” Williams wrote in a Facebook post recounting the incident.

“That’s when you started to hear folks let out a few screams,” he told The Post.

Williams, who studied aviation, said he feared the plane might stall. After climbing steeply for three to five seconds

Accounts of an alarming pitch attitude should be treated with a certain amount of caution, given that the weather would have meant that no horizon was visible. There doesn't appear to have been any sudden gain in height before the 777 headed earthwards.

tdracer

16th Feb 2023, 18:25

You can expect the CVR and FDR being unobtainable for all the usual reasons. Some of those are not wrong.

QAR is a different beast, though the data might not be allowed to leave a certain computer or even a computer station. That information, alongside honest best crew recollection, will uncover the dynamics in very precise detail.

I was thinking the same - the QAR can be downloaded in minutes, so if the crew reported anything after landing the QAR could have been readily downloaded during the 2.5-hour turnaround.

RickNRoll

17th Feb 2023, 01:03

Accounts of an alarming pitch attitude should be treated with a certain amount of caution, given that the weather would have meant that no horizon was visible. There doesn't appear to have been any sudden gain in height before the 777 headed earthwards.
Of it wasn't climbing any faster but pitching up higher?

Denti

17th Feb 2023, 05:00

Capn Bloggs

17th Feb 2023, 06:57

I'm having trouble reconciling the increasingly high speed at the bottom of the descent. If it encountered decreasing-performance windshear, I'd expect the speed to stay low during the descent with the nose level or maybe slightly low (close to the sticker shaker at full power to minimise altitude-loss). Even if it then encountered very strong increasing-performance windshear, the speed would start increasing, but should have been controlled enough not to get so fast while still descending. The nose would still have been somewhere near the horizon and as soon as the headwind came back on, the windshear escape manoeuvre would have the nose way up.

This appears to have just nosed over, with power still on, and rapidly accelerated with a big snatch-pull to recover, as if someone has just shoved the stick forward, held it, then pulled up.

If this was caused by a microburst, unless a dry microburst, IMO the convective cloud creating it would have been obvious on the aircraft weather radar.

This is from the FR24 data CSV (Date-Time, altitude, groundspeed):

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/378x443/ual1722_1cd9e61fbb3dd3cd00f3e53e72fb69c1778289db.jpg

212man

17th Feb 2023, 12:34

I was thinking the same - the QAR can be downloaded in minutes, so if the crew reported anything after landing the QAR could have been readily downloaded during the 2.5-hour turnaround.
Surely the QAR would have been downloaded per the FDM programme, and this event detected anyway?

tdracer

17th Feb 2023, 17:55

Isn’t the QAR transmitted automatically during taxi in anyway? I know all the data for flight data monitoring is at my companies headquarter usually when the parking checklist is done. And that is without SATCOM, once that is installed it will be transmitted throughout the flight in regular intervals.
It depends. The hardware varies - some can download automatically via Wi-Fi, some via satellite, and some need a hardwired connection. Satellite is fairly unusual - the QAR records a massive amount of data, so it's rather expensive to transmit all that via satellite (some are programed to download specific unusual events - or small data subsets - to keep the satellite fees down). Others respond to and download when queried from base. When I was still working the 747-8, GE had installed an "EMU" - Engine Monitor Unit - that could automatically download via Wi-Fi at the terminal (assuming the terminal was properly equipped), or send out specific event data sets via satellite. The operators started complaining that the EMU was using way too much satellite bandwidth and it was costing them too much money for routine data reports, so GE revised the EMU software to send fewer specific event data sets.
All that being said, I have no idea what UAL has on their 777s - however the point is that a QAR download would be quick and easy regardless of the download method used. It also would likely contain far more data - in greater detail - than the FDR.

weatherdude

17th Feb 2023, 21:08

The area was busy at the time, but not exactly at the plane's position, this is the radar image Reflectivity at 00:54 UTC, other time steps via menu (https://weather.us/radar-us/1562-w-205-n/reflectivity/PHKM_20221219-005402z.html)

These are the Doppler speeds at the same time (https://weather.us/radar-us/1562-w-205-n/velocity-kmh/PHKM_20221219-005434z.html)

If I understood the position right, the plane would have been outside of any severe weather. Please correct me if I got the position wrong.

spornrad

17th Feb 2023, 21:45

Local time is UTC-10. So 0:50 UTC should be 2:50 PM local. (Edit: was confused with indicated time on the linked page, may depend on location when opening the page)

weatherdude

17th Feb 2023, 21:51

So these UTC times are wrong? FR24 times (https://www.pprune.org/accidents-close-calls/651344-united-777-dives-after-takeoff-ogg-3.html#post11387186)

spornrad

17th Feb 2023, 21:55

Time of the upset in FR24 is 00:51 UTC (think 24:51 - 10 h = 14:51 = 2:51PM)

weatherdude

17th Feb 2023, 22:19

Good. Then the radar images I posted are correct. I set UTC for the page. Maybe you have another time zone set on weather.us?

spornrad

17th Feb 2023, 22:40

My bad. Your linked page shows me 12/18/2022 06:54:02 PM as time stamp. In the link I see your correct z time. Will delete my posted link. The page seems to show a different timezone, even for historic data. Sorry about the confusion.

weatherdude

17th Feb 2023, 23:01

You decide about the time zone for the page. There is the gear icon for settings.

VHOED191006

19th Feb 2023, 07:25

DaveReidUK

19th Feb 2023, 08:35

I don't know how Simon on the Avherald can come to that conclusion. Planes just don't loose 1,400ft within the span 12 seconds. That comes out to a roughly -7000fpm descent (TAC reports -8,600fpm, so close enough). Something did indeed happen during that departure. FR24 doesn't just randomly start outputting such extreme values.

Simon is a great journalist when it comes to fact, research and reporting. He is excellent at ferreting out information from all sorts of sources.

Sadly, though, he has a pretty shaky grasp of technical stuff (like many journalists) - some of his previous ADS-B-based "analyses" have been woeful.

Stick to what you do well, Simon.

ManaAdaSystem

20th Feb 2023, 07:56

I don't know how Simon on the Avherald can come to that conclusion. Planes just don't loose 1,400ft within the span 12 seconds. That comes out to a roughly -7000fpm descent (TAC reports -8,600fpm, so close enough). Something did indeed happen during that departure. FR24 doesn't just randomly start outputting such extreme values.

Setting up a 7000+ rate of descent in 12 seconds is not that easy. You would have to push hard and fast forward. Negative G.
This rate points toward a windshear/microburst event.
A microburst may be difficult to see on a radar. I flew through one many years ago. Only had small red dots on the radar. Heavy rain in the shear, speed increased fast followed by fast drop in speed as we passed under the microburst. Massive rain. All we could manage was a steady descent at ref -10, throttles fully forward and one dot low on the glide.
As we passed out of the shear, airspeed increased really fast again.

212man

20th Feb 2023, 17:23

Setting up a 7000+ rate of descent in 12 seconds is not that easy. You would have to push hard and fast forward. Negative G.

I don’t buy that at all. 200 Kts is about 20,000ft/min. Sine 20 degrees is about 0.34. So setting -20 degrees would easily give you 7000 ft/min rod and easily achieved in 12 seconds.

I used to fly rotary and had an opportunity to do some work with the senior Honeywell scientist on EGPWS. I took him for a jump seat ride once and I showed him how quickly rate of descent built up with pitch down. From 145 kts cruise I selected -5, -10, -15 degrees pitch down (separate demos). The rate of increase in rate of descent was eye watering. It was connected to seeing how the Mode 1 alerts could be improved.

FlightDetent

20th Feb 2023, 19:08

Wonderful story, love it. This may be anothercase where the system saved lives numerous.

Do you think it may have been the man himself?

Capn Bloggs

20th Feb 2023, 22:59

So setting -20 degrees would easily give you 7000 ft/min rod and easily achieved in 12 seconds.
But we're not talking about a chopper, we're talking about an in-trim (I assume) Boeing 777 that was probably around 10° nose-up. To have the nose go down to -20° in 12 seconds would indeed be "not that easy". It would have required some very positive action on somebody's/something's part.

Vessbot

21st Feb 2023, 17:56

DaveReidUK

21st Feb 2023, 19:17

I suspect that had there been even an incipient stall, albeit not an actual one, that might still have triggered a few flags in the training department.

Zeffy

26th Apr 2023, 21:14

Latest from Jon Ostrower:
https://theaircurrent.com/aviation-safety/ntsb-preliminary-report-united-1722-maui/

NTSB releases uninformative preliminary report on United Maui dive
Air safety reporting by The Air Current is provided without a subscription as a public service. Please subscribe for all scoops, in-depth reporting and analyses.

The National Transportation Safety Board quietly released a bare-bones and uninformative preliminary report as part of its investigation into the United Airlines Boeing 777-200 that went into a sharp dive and recovery shortly after takeoff from Maui in December.

The investigation into the still publicly unexplained December 18 dive is unusual for the NTSB, which launched the investigation on February 14 only after the occurrence was revealed publicly by The Air Current on February 12. At the time, the NTSB said that it expected a preliminary report within two to three weeks.

The NTSB almost always begins an inquiry immediately following an incident or accident — in sharp contrast to the eight weeks that followed the incident aboard United 1722 — and the lack of a template for a multi-month delay has been awkward for the safety board.

The NTSB initially told TAC on April 21 that while the investigation was still ongoing, it was not planning to release a preliminary report and that was common for some investigations. After TAC sought an accounting of earlier NTSB inquiries that did not receive preliminary reports, the agency clarified and said after seeking an internal accounting of similar incidents "there was no such list."

NTSB spokesman Peter Knudson attributed the confusion to the NTSB having "updated some report writing and releasing processes and it seems there was a lack of clarity related to the preliminary report releasing process."

"There will, in fact, be a preliminary report," said Knudson on April 24. "It will not, however, contain a factual narrative but only 'data blocks' as they are known."

The just-released preliminary report was devoid of any contextual information beyond the incident's location, the flight's destination and the aircraft type and registration. The board's initial February 14 tweet announcing the investigation described the incident as one "in which a United Airlines 777 lost altitude before recovering shortly after departing." That description was not included in the just-released preliminary report, which does not make it clear what the NTSB is investigating.

"The narrative will be included in the final report along with the probable cause and any contributing factors," said Knudson, who expected the final report on the Maui incident to be released this summer.

Write to Jon Ostrower at [email protected]

RichardJones

27th Apr 2023, 00:04

I don't know what the non handling pilot was doing. However to help stay out of trouble, do this. Select the required flap setting. Keep your hand on the lever until the indication, indicates what you have selected. When that is done, realise the lever, whether it be u/c or flap while in transit, keep your hand on the lever. I have seen it from time to time.. Select and forget? Not good enough. Asking for trouble, if that was what happened.

B-757

27th Apr 2023, 02:48

Keep your hand on the lever until the indication, indicates what you have selected...Really??..Impossible..Non-flying pilot supporting the PF by setting headings, altitudes, radio frquencies etc during a climb in a busy airspace..Cannot do that with the hand on the flap lever..

Fly Safe,
B-757

fdr

27th Apr 2023, 06:40

golly that was untidy. The QAR data will tell the full story, the continued flying and delayed reporting will have lost the DFDR. Doesn't sound like a W/shear event, it does hint of disorientation, and crew input resulting in the dive and recovery. The report of going through an extra flap setting is not that big a deal on a B777, for that setting, getting rid of the LE slats would be a bigger problem, in the absence of evidence, that may have been more of a problem, but the B777 will tolerate a F5-F1 error without becoming catastrophic. The response seems to be from the flight crew, not the weather, if the GS has any validity. Not a nice day out.

RichardJones

27th Apr 2023, 08:30

BFSGrad

11th Aug 2023, 00:42

Vertical speed and pitch attitude continued a negative downward trend to reach a maximum of -8,536 feet per minute and -16.74 degrees respectively while at 1,386 feet (radio altitude)

Docket (https://data.ntsb.gov/Docket?ProjectID=106734)

Capn Bloggs

11th Aug 2023, 00:54

This'll be good...

Wow!

punkalouver

11th Aug 2023, 04:08

Pretty much as I expected. No one was monitoring the instruments for a significant period of time. This happened after an issue with flap selection/overspeed. The focus by the pilot flying on flap concerns instead of instrument scan was long enough to result in an undesired flight condition.

While hand-flying is nice, using the autopilot in more challenging conditions can have the advantage of allowing one to have more focus on other distractions while the automatics take care of aircraft attitude.

Capn Bloggs

11th Aug 2023, 07:28

NTSB final report via Flightradar 24:
https://www.flightradar24.com/blog/wp-content/uploads/2023/08/NTSB_United_777_Altitude_Final_Report.pdf

AerocatS2A

11th Aug 2023, 07:43

NTSB final report via Flightradar 24:
https://www.flightradar24.com/blog/wp-content/uploads/2023/08/NTSB_United_777_Altitude_Final_Report.pdf

They managed to turn a pretty innocuous mistake into a near-disaster. I find it interesting that the PF's reaction to impending overspeed during initial climb was to reduce thrust rather than pitch up.

snl13

11th Aug 2023, 08:39

They managed to turn a pretty innocuous mistake into a near-disaster. I find it interesting that the PF's reaction to impending overspeed during initial climb was to reduce thrust rather than pitch up.

Might be different philosophy since I am low experience and flying on airbus but first reaction would be to use full automation available, be sure to be in proper lateral/vertical mode and select the speed. This taking about 5 seconds.

Maybe they reduced the thrust because a pitch up would cause a really high roc potentially leading to an altitude bust. But even then you can still go, disregard the cleared altitude and do it as you would during an unreliable airspeed climb to MSA if needed.

1southernman

11th Aug 2023, 11:40

Might be different philosophy since I am low experience and flying on airbus but first reaction would be to use full automation available, be sure to be in proper lateral/vertical mode and select the speed. This taking about 5 seconds.

Maybe they reduced the thrust because a pitch up would cause a really high roc potentially leading to an altitude bust. But even then you can still go, disregard the cleared altitude and do it as you would during an unreliable airspeed climb to MSA if needed.

Just an observation and not meant to sound "sagey"...I flew early "glass" Boeings and A320...When things got a little hairy I always went manual to put things back in order then reintroduced auto as needed...Worked every time... In spite of the inevitable mistakes and thankfully having flown with a bunch of pros I was very blessed to have been violation/incident/accident free...Many FSAPs, however, were generated just in case...:)...

snl13

11th Aug 2023, 12:10

Just an observation and not meant to sound "sagey"...I flew early "glass" Boeings and A320...When things got a little hairy I always went manual to put things back in order then reintroduced auto as needed...Worked every time... In spite of the inevitable mistakes and thankfully having flown with a bunch of pros I was very blessed to have been violation/incident/accident free...Many FSAPs, however, were generated just in case...:)...

I fully agree if you intend to ‘fly the plane’ but if it’s keeping everything manual and at the same time go nose down in a critical phase of flight I would not feel confortable and that’s against everything I have been taught during my PPL/CPL and then type rating (and since I have low experience I can only rely on that).

1southernman

11th Aug 2023, 13:04

I fully agree if you intend to ‘fly the plane’ but if it’s keeping everything manual and at the same time go nose down in a critical phase of flight I would not feel confortable and that’s against everything I have been taught during my PPL/CPL and then type rating (and since I have low experience I can only rely on that).

Mmm...Yep fly the plane is the goal...:) You should do it however you're taught and comfortable with...Anyway I don't have a dog in the hunt anymore so I'm now going outside and play....Blue skies and stay safe...

BFSGrad

11th Aug 2023, 14:27

Noted one inconsistency between the NTSB final report and the NTSB form 6120.1: Former lists the captain’s time in type as 500; latter lists captain’s time in type as 5,000 (also lists PIC time in type as 300).

megan

12th Aug 2023, 02:52

Noted one inconsistency between the NTSB final report and the NTSB form 6120.1Inconsistencies are sometimes found in their documentation, nothing new I'm afraid.

172_driver

12th Aug 2023, 12:39

I fully agree if you intend to ‘fly the plane’ but if it’s keeping everything manual and at the same time go nose down in a critical phase of flight I would not feel confortable and that’s against everything I have been taught during my PPL/CPL and then type rating (and since I have low experience I can only rely on that).

Have they taught you not to pitch down while in manual flight?

snl13

12th Aug 2023, 15:01

Have they taught you not to pitch down while in manual flight?

yes only up, until I reach the sun.

More seriously I meant not to switch focus to something else than looking outside/instrument scanning and so avoid situations like this where the plane go in such a nose down attitude / vertical rate / loss of SAW.

BFSGrad

12th Aug 2023, 15:07

Inconsistencies are sometimes found in their documentation, nothing new I'm afraid.

I mentioned that discrepancy because there were some initial rumors that both pilots were relatively low time-in-type. Assuming the 6120.1 data is accurate, the captain had considerable 777 experience but was a relatively new 777 captain, while the FO was relatively low time-in-type.

TachyonID

12th Aug 2023, 21:37

They managed to turn a pretty innocuous mistake into a near-disaster. I find it interesting that the PF's reaction to impending overspeed during initial climb was to reduce thrust rather than pitch up.

Yeah, that was exactly my question-- How siutationally unaware was the PF to reduce thrust without understanding the big picture. On climb-out? It's a confusing choice of control inputs.

AerocatS2A

13th Aug 2023, 04:31

Does the B777 pitch down with a reduction of thrust when flying manually or does its FBW compensate? Could that have exacerbated the descent?

Disregard, I see from the FCOM that it compensates.

Rick2023

14th Aug 2023, 13:13

I see similarities between this incident and the Emirates 777 botched takeoff in Dubai. Perfect aircraft, alert and trained crew just sitting there watching a complete mess unfold and doing nothing at all until a well developed unsafe condition exists.

Tip of the iceberg I reckon.

DaveReidUK

14th Aug 2023, 21:55

NTSB final report via Flightradar 24:
https://www.flightradar24.com/blog/wp-content/uploads/2023/08/NTSB_United_777_Altitude_Final_Report.pdf

Worth noting that there's no mention of a stall in the NTSB report.

RickNRoll

20th Aug 2023, 03:43

This all happened because of confusion about the flaps setting. Did the PNF confirm what he heard verbally. 99.9% of the time it's the same action, just one step, done. In this case it was supposed to be two steps.

AerocatS2A

20th Aug 2023, 06:33

Worth noting that there's no mention of a stall in the NTSB report.
No, because he selected Flap 15 instead of 5 which is a "safe" setting in terms of inadvertent stall. It all happened because the Captain stopped flying the plane when he got distracted by the fact the flaps didn't go to where he expected them to.

RickNRoll

20th Aug 2023, 06:55

Watson1963

20th Aug 2023, 08:57

https://data.ntsb.gov/Docket?ProjectID=106734

1southernman

20th Aug 2023, 13:06

Very dynamic event with a big loss of SA...Would've been beneficial to have CVR but the crew seemed forthcoming and the data tells the story pretty well...Eventually the crew retrained and went back to the line...If there were issues, current or past, with them individually (training, etc.) hopefully it was addressed...I assume they are better for it and the rest of us can learn from it...

punkalouver

21st Aug 2023, 01:23

No, because he selected Flap 15 instead of 5 which is a "safe" setting in terms of inadvertent stall. It all happened because the Captain stopped flying the plane when he got distracted by the fact the flaps didn't go to where he expected them to.

He was distracted because there was an overspeed warning and he didn't know why. He had to check everything including flaps.

I disagree with the second quoted statement. Just continue flying the aircraft and don't let the speed exceed the maximum allowable. That would mean continuing to look at the PFD and pitching the nose up enough to keep the speed from getting too high. If one needs to 'check everything', they can simply engage the autopilot, ensure the automatics are operating as desired and then start looking around. In addition, the speed tape on the PFD which the pilot should be looking at will be giving information about what flap setting has been selected.

As for the F/O, he should be looking at the flap lever when the flaps are being selected. Then it is highly unlikely that the wrong selection will be made. PF says 'Flaps 5", PM says 'Flaps 5" then looks at the flaps lever while reaching for it and ensures that it goes to the proper detent. Then look at the flap indicator and see that it changes to an amber 5, confirming proper selection. Then look back at the PFD. All takes about three seconds.

RickNRoll

22nd Aug 2023, 01:29

1southernman

22nd Aug 2023, 22:02

What did the training teach them that they missed?

Luckily I never had to do it but I assume that there was CRM/SOP re-enforcement in there along with line oriented training (LOFT) tailored to this event...Also maybe PTSD counseling...Not sure how it's structured but they didn't need to be taught how to fly again :)..The facts are that the event occurred, thankfully they recovered in time, FOQA data documented it, and it was addressed...They wouldn't have been turned loose otherwise...

Capn Bloggs

23rd Aug 2023, 00:49

Not sure how it's structured but they didn't need to be taught how to fly again
Eh? That appears to be the only failing here; the captain's instrument cross-reference was poor. He fixated on the flaps, instead of flying and looking at the flap position. An hour sharpening his basic IF skills would have been the most valuable retraining IMO. All that other stuff worked well; reinforce the other stuff if you want but the lack of flying skill in an unusual situation caused this. Not that I am criticising him for the lack of skill; the fact that automation is rammed down our throats makes this sort of incident more and more likely because people's flying skills naturally atrophy.

FlightDetent

23rd Aug 2023, 06:15

Speed tape confusion, anyone? An unforeseen red stripe descends unexpectedly on top of your speed index....

Easy to play in the SIM with predictable results if the scenario is set up well. Ugly but educative.

1southernman

24th Aug 2023, 01:49

Eh? That appears to be the only failing here; the captain's instrument cross-reference was poor. He fixated on the flaps, instead of flying and looking at the flap position. An hour sharpening his basic IF skills would have been the most valuable retraining IMO. All that other stuff worked well; reinforce the other stuff if you want but the lack of flying skill in an unusual situation caused this. Not that I am criticising him for the lack of skill; the fact that automation is rammed down our throats makes this sort of incident more and more likely because people's flying skills naturally atrophy.

The flying skills vs automation is a big deal and reminds me of the Dog and Pilot joke https://ci3.googleusercontent.com/proxy/LF25hMI50iM75DTrcPDnIm0esxo3VKzBvQM3EfzVZA7hwHDKXRw6h1zRxHmS 4owQAQLB_bsOzuLyyJ-vyoWED2yK=s0-d-e1-ft#https://www.pprune.org/images/smilies/smile.gif...My speculation is that the crew's skills (CRM, SOP, IF, etc.) as well as their mental state post event were assessed and addressed...I think it would have been comprehensive and more than just time in the "box"...Like the accident chain it's always more than one thing...Unfortunately this wouldn't be the training department's first rodeo and not the last...

Uplinker

24th Aug 2023, 13:11

..Really??..Impossible..Non-flying pilot supporting the PF by setting headings, altitudes, radio frquencies etc during a climb in a busy airspace..Cannot do that with the hand on the flap lever..
Fly Safe,
B-757

Not impossible. You can, especially from RHS. When flying in an airline with this hand-on-lever SOP, if I was RHS PM and moved the flaps, then immediately got a new heading request or whatever from PF, I used my other hand, or swapped hands on the flap lever and used the original hand.

I see similarities between this incident and the Emirates 777 botched takeoff in Dubai. Perfect aircraft, alert and trained crew just sitting there watching a complete mess unfold and doing nothing at all until a well developed unsafe condition exists.

Tip of the iceberg I reckon.It is a bit worrying that these seemingly basic excursions and errors are happening. Is pilot training and basic skills practice being cut too much these days?

Speed tape confusion, anyone? An unforeseen red stripe descends unexpectedly on top of your speed index....

Easy to play in the SIM with predictable results if the scenario is set up well. Ugly but educative.

Yes, I have often thought that the modern speed tape is "upside down". i.e. the higher you look on the speed tape the higher the speed, but that is opposite - in terms of the pitch you need to apply - to "move" the speed tape in a given 'direction'.
On the altitude tape, pitching the nose up makes the aircraft go higher on the altitude scale, which is more intuitive. Maybe, when PF saw the red bar suddenly descend on his speed tape, he instinctively reduced thrust and pitched hard down to avoid it in the heat of the moment, as you would pitch down to go lower on the altitude scale. (see reply to middle quote).

With a round dial speed gauge with a pointer, the lower speeds tend to be on the right half of the dial, so at the slower, more critical speeds, the speed pointer moves intuitively; pitch up: speed reduces - pitch down: speed increases, which makes more sense.
.