Go Back  PPRuNe Forums > Flight Deck Forums > Accidents and Close Calls
Reload this Page >

United 777 "dives" after takeoff from OGG

Accidents and Close Calls Discussion on accidents, close calls, and other unplanned aviation events, so we can learn from them, and be better pilots ourselves.

United 777 "dives" after takeoff from OGG

Old 17th Feb 2023, 22:40
  #61 (permalink)  
 
Join Date: Jul 2009
Location: France
Age: 62
Posts: 98
Likes: 0
Received 0 Likes on 0 Posts
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.
spornrad is offline  
Old 17th Feb 2023, 23:01
  #62 (permalink)  
 
Join Date: Jun 2009
Location: Oklahoma
Age: 65
Posts: 49
Likes: 0
Received 0 Likes on 0 Posts
You decide about the time zone for the page. There is the gear icon for settings.
weatherdude is offline  
Old 19th Feb 2023, 07:25
  #63 (permalink)  
 
Join Date: Jan 2023
Location: I would tell you, but my GPS keeps getting jammed
Posts: 169
Received 49 Likes on 20 Posts
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.
VHOED191006 is offline  
Old 19th Feb 2023, 08:35
  #64 (permalink)  
Thread Starter
 
Join Date: Jan 2008
Location: Reading, UK
Posts: 15,977
Received 299 Likes on 154 Posts
Originally Posted by VHOED191006
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.
DaveReidUK is online now  
Old 20th Feb 2023, 07:56
  #65 (permalink)  
 
Join Date: Aug 2000
Posts: 1,501
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by VHOED191006
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.
ManaAdaSystem is offline  
Old 20th Feb 2023, 17:23
  #66 (permalink)  
 
Join Date: Oct 1999
Location: Den Haag
Age: 57
Posts: 6,381
Received 384 Likes on 221 Posts
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.
212man is offline  
Old 20th Feb 2023, 19:08
  #67 (permalink)  

Only half a speed-brake
 
Join Date: Apr 2003
Location: Commuting not home
Age: 46
Posts: 4,324
Received 6 Likes on 5 Posts
Wonderful story, love it. This may be anothercase where the system saved lives numerous.

Do you think it may have been the man himself?
FlightDetent is offline  
Old 20th Feb 2023, 22:59
  #68 (permalink)  
 
Join Date: Mar 2002
Location: Seat 1A
Posts: 8,644
Received 119 Likes on 67 Posts
Originally Posted by 212man
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.
Capn Bloggs is online now  
Old 21st Feb 2023, 17:56
  #69 (permalink)  
 
Join Date: Sep 2016
Location: USA
Posts: 868
Likes: 0
Received 22 Likes on 11 Posts
Originally Posted by tubby linton
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.
How does it suggest that?
Vessbot is offline  
Old 21st Feb 2023, 19:17
  #70 (permalink)  
Thread Starter
 
Join Date: Jan 2008
Location: Reading, UK
Posts: 15,977
Received 299 Likes on 154 Posts
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.
DaveReidUK is online now  
Old 26th Apr 2023, 21:14
  #71 (permalink)  
 
Join Date: Feb 2006
Location: USA
Posts: 487
Likes: 0
Received 0 Likes on 0 Posts
Air Current

Latest from Jon Ostrower:
​​​​​​https://theaircurrent.com/aviation-s...ted-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]
Zeffy is offline  
Old 27th Apr 2023, 00:04
  #72 (permalink)  
 
Join Date: Dec 2020
Location: Yes
Posts: 219
Received 36 Likes on 22 Posts
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.

Last edited by RichardJones; 27th Apr 2023 at 01:02.
RichardJones is online now  
Old 27th Apr 2023, 02:48
  #73 (permalink)  
 
Join Date: Feb 2011
Location: usa
Posts: 83
Likes: 0
Received 3 Likes on 3 Posts
Originally Posted by RichardJones
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
B-757 is offline  
Old 27th Apr 2023, 06:40
  #74 (permalink)  
fdr
 
Join Date: Jun 2001
Location: 3rd Rock, #29B
Posts: 2,985
Received 926 Likes on 271 Posts
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.
fdr is offline  
Old 27th Apr 2023, 08:30
  #75 (permalink)  
 
Join Date: Dec 2020
Location: Yes
Posts: 219
Received 36 Likes on 22 Posts
Originally Posted by B-757
..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
I didn't know whether to laugh or cry. So I did both.🤣😭
RichardJones is online now  
Old 11th Aug 2023, 00:42
  #76 (permalink)  
 
Join Date: Mar 2015
Location: Virginia, USA
Posts: 496
Likes: 0
Received 34 Likes on 24 Posts
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
BFSGrad is offline  
Old 11th Aug 2023, 00:54
  #77 (permalink)  
 
Join Date: Mar 2002
Location: Seat 1A
Posts: 8,644
Received 119 Likes on 67 Posts
This'll be good...

Wow!

Last edited by Capn Bloggs; 11th Aug 2023 at 01:04.
Capn Bloggs is online now  
Old 11th Aug 2023, 04:08
  #78 (permalink)  
 
Join Date: Nov 2004
Location: Here, there, and everywhere
Posts: 1,150
Likes: 0
Received 24 Likes on 14 Posts
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.

Last edited by punkalouver; 11th Aug 2023 at 21:52.
punkalouver is offline  
Old 11th Aug 2023, 07:28
  #79 (permalink)  
 
Join Date: Mar 2002
Location: Seat 1A
Posts: 8,644
Received 119 Likes on 67 Posts
NTSB final report via Flightradar 24:
https://www.flightradar24.com/blog/w...nal_Report.pdf
Capn Bloggs is online now  
Old 11th Aug 2023, 07:43
  #80 (permalink)  
 
Join Date: Jan 2004
Location: Here and there
Posts: 3,118
Received 19 Likes on 15 Posts
Originally Posted by Capn Bloggs
NTSB final report via Flightradar 24:
https://www.flightradar24.com/blog/w...nal_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.
AerocatS2A is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.