Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

Boeing 747-400 water landing evacuation procedure

Tech Log The very best in practical technical discussion on the web

Boeing 747-400 water landing evacuation procedure

Old 9th Nov 2019, 13:42
  #1 (permalink)  
Thread Starter
 
Join Date: Jun 2019
Location: Tana
Posts: 0
Boeing 747-400 water landing evacuation procedure

Today I went on the Internet and I found this:

The link, if you care to click it, will take you straight to the 0:51 mark. What's interesting to me here is how the PA describes the evacuation procedure: "For passengers on the upper deck, if the water landing occurs, you should [go] downstairs and exit through main deck doors".

Two questions here. One, ARE THEY SERIOUS!? Is that a real evacuation procedure!? A layman passenger, in shock from water landing and possibly injured, should head down a darn steep flight of stairs (which may or may not still be there) to exit the plane!? Or is the water landing of such aircraft was considered so devastating that nobody was expected to survive anyway and this is just a keep-em-calm announcement?

And two, why are both wing and upper deck inflatable slides disabled in case of a water landing? What's the big difference? Beside faster evacuation, those large slides could be used as large rafts for passengers. Can the remaining eight hold ALL passengers of which there could be 660?
UltraFan is online now  
Old 10th Nov 2019, 03:19
  #2 (permalink)  
 
Join Date: Aug 2007
Location: Seattle KBFI
Posts: 109
The slides that you refer to do not also double as rafts. And the overwing slide ( door 3) would extend aft and interfere with the door 4 slide, instead of passing underneath it, as it would in a land evacuation.

And you will be hard pressed to find a 744 with that number of pax, most are going to max out at under 400.

Last edited by bigduke6; 12th Nov 2019 at 20:17.
bigduke6 is offline  
Old 10th Nov 2019, 07:38
  #3 (permalink)  
CCA
 
Join Date: Oct 1999
Location: Up there
Posts: 170

As you can see doors 1,2,4 & 5 would result in slide-RAFTS that are basically flat (as seen door 1) the upper deck slide would result in slippery slide and swimming, if itís cold you might be dead before you swam to a raft.
CCA is offline  
Old 10th Nov 2019, 07:58
  #4 (permalink)  
 
Join Date: Feb 2001
Location: The Winchester
Posts: 5,493
Originally Posted by UltraFan View Post
Today I went on the Internet and I found this:
https://youtu.be/n9wG2FdGhDU?t=51

The link, if you care to click it, will take you straight to the 0:51 mark. What's interesting to me here is how the PA describes the evacuation procedure: "For passengers on the upper deck, if the water landing occurs, you should [go] downstairs and exit through main deck doors".

Two questions here. One, ARE THEY SERIOUS!? ...
You are a bit late on the outrage bus since that slide configuration for the 744 has been around since the late 80s and AFAIK is industry wide for the machine.

It's been a while since I flew the QOTS but from memory I agree with the previous replies, ie..

The upper deck slides are not slide rafts because the position of the waterline post a ditching using an upper deck slide will mean any user gets dumped in the water at high speed..which has CCA has pointed out then leaves you very exposed.

Door 3 slides are not deployed in a ditching since when inflated the assembly would float aft at the inboard end of the wing trailing edge and would interfere with the sliderafts at Doors 4 (as bigduke6 explained...).

As a result the aircraft is equipped (as I recall it) with Dual lane sliderafts at Doors 1,2 4 and 5 only...oh, and FWIW the system and procedures have been "tested in the field"..

​​​​​China Airlines 605

"Immediately after the aircraft came to rest in the water, crew members ensured that all passengers donned life jackets and evacuated onto eight of the ten main deck emergency exits. These exits (as on all 747s) are equipped with inflatable evacuation slide/rafts for ditching emergencies. The passenger cabin remained completely above water during the evacuation,"

Last edited by wiggy; 10th Nov 2019 at 08:17.
wiggy is offline  
Old 10th Nov 2019, 09:02
  #5 (permalink)  
 
Join Date: Apr 2015
Location: Netherlands
Posts: 87
In the you-tube film above, the slats are retracted upon deployment of the thrust reversers, which makes sense. But when the TR are closed, the slats -while taxying- are deployed again. I'm not a pilot, but an engineer, so I've no idea why that is. Can anybody enlighten me? .
washoutt is offline  
Old 10th Nov 2019, 09:13
  #6 (permalink)  
 
Join Date: Feb 2001
Location: The Winchester
Posts: 5,493
Originally Posted by washoutt View Post
In the you-tube film above, the slats are retracted upon deployment of the thrust reversers, which makes sense. But when the TR are closed, the slats -while taxying- are deployed again. I'm not a pilot, but an engineer, so I've no idea why that is. Can anybody enlighten me? .
As I recall it ( with a "it's been ten years plus so health warning") the inboard/mid-span leading edges retract on selection of reverse to prevent them being damaged during reverse thrust operation ( ?FOD). Once reverse is cancelled the LEs should then automatically return to the position appropriate to the selected Flap setting..(and FWIW the slats work in harness/are controlled by the Flap setting/Flap lever, there's no separate slats control). Bearing that in mind..

1. On approach/touchdown with Flap selected the inboard/mid LEs will be "out".

2. On roll out with reverse selected the inboard/mid LEs will motor "in",

3. Once reverse is cancelled, usually towards the very end of the rollout, those LEs will then motor "out" again because usually at that point landing flap is still selected,

4. Once off the runway and when the after landing procedure is performed the flap is selected up and the LEs will motor "in" again..

That's the theory.....

Last edited by wiggy; 10th Nov 2019 at 09:43.
wiggy is offline  
Old 10th Nov 2019, 10:05
  #7 (permalink)  
 
Join Date: Aug 2015
Location: Sunnydale
Posts: 159
Originally Posted by wiggy View Post
As I recall it ( with a "it's been ten years plus so health warning") the inboard/mid-span leading edges retract on selection of reverse to prevent them being damaged during reverse thrust operation ( ?FOD). Once reverse is cancelled the LEs should then automatically return to the position appropriate to the selected Flap setting..(and FWIW the slats work in harness/are controlled by the Flap setting/Flap lever, there's no separate slats control). Bearing that in mind..

1. On approach/touchdown with Flap selected the inboard/mid LEs will be "out".

2. On roll out with reverse selected the inboard/mid LEs will motor "in",

3. Once reverse is cancelled, usually towards the very end of the rollout, those LEs will then motor "out" again because usually at that point landing flap is still selected,

4. Once off the runway and when the after landing procedure is performed the flap is selected up and the LEs will motor "in" again..

That's the theory.....
Unless the air/ground reverse logic fails when you take off out of JNB and then you have a very exciting take off 😱
back to Boeing is offline  
Old 10th Nov 2019, 11:29
  #8 (permalink)  
 
Join Date: Feb 2001
Location: The Winchester
Posts: 5,493
Originally Posted by back to Boeing View Post


Unless the air/ground reverse logic fails when you take off out of JNB and then you have a very exciting take off 😱
Yessssss.....I sort of alluded to something like that being a possibility in the original version of my post and then edited it out.....
wiggy is offline  
Old 10th Nov 2019, 15:11
  #9 (permalink)  
 
Join Date: May 2014
Location: UK
Posts: 180
744 Leading edge flaps (not slats)

More for LE flap panel fatigue life than FOD or structural interference, it seems.
Discussion here, see the last 2 posts from Cougar:
https://www.airlinepilotforums.com/a...p/t-64414.html
Which also covers the BA incident at JNB in 2009.
https://avherald.com/h?article=4198598d

MB
Minnie Burner is offline  
Old 11th Nov 2019, 07:55
  #10 (permalink)  
 
Join Date: Dec 2001
Location: Europe
Posts: 303
What the heck is a water landing? If it's happening on water, and not on land, it's not a landing.
733driver is offline  
Old 11th Nov 2019, 09:49
  #11 (permalink)  
 
Join Date: Apr 2015
Location: Netherlands
Posts: 87
Thanks Wiggy, that makes sense. But I also noticed that the outboard LE stays deployed when the TR is activated. Will that one not be FODded?
washoutt is offline  
Old 11th Nov 2019, 11:31
  #12 (permalink)  
 
Join Date: Feb 2001
Location: The Winchester
Posts: 5,493
As I recall it I think FOD might have been just one of the reasons for the sequencing ( hence the "?" in front of my FOD comment) - the discussion in the link Minnie provided gives much more of the fine detail than I can remember....
wiggy is offline  
Old 11th Nov 2019, 18:22
  #13 (permalink)  
Thread Starter
 
Join Date: Jun 2019
Location: Tana
Posts: 0
Originally Posted by bigduke6 View Post
The slides that you refer to do not also double as rafts. And the overwing slide ( door 3) would extend aft and interfere with the door 4 slide, instead of passing underneath it, as it would in a land evacuation.

And you will be hard pressed to find a 744 with that number of pax, most are going to max our at under 400.
Thanks for the info. And yes, you can (or rather, could) find 744 with that number of passengers. I clearly remember the number of passengers of the ill-fated JAL123 was 524. Japanese airlines easily max out Boeing 777 with 512 on JAL and 537 (I think) on ANA, so I suppose they did the same with 744.
UltraFan is online now  
Old 11th Nov 2019, 18:25
  #14 (permalink)  
Thread Starter
 
Join Date: Jun 2019
Location: Tana
Posts: 0
Originally Posted by wiggy View Post
You are a bit late on the outrage bus
Oh, hardly an outrage. Never flew it, never flew on it, and by the looks of it, the chances are slim for either of those activities. Just a bit surprised. Or maybe I should join the trend and be outraged about 748 grandfathered certification? Hmmm... Naaah.
UltraFan is online now  
Old 11th Nov 2019, 19:48
  #15 (permalink)  
 
Join Date: Jun 2001
Location: FNQ ... Still!
Posts: 3,411
Several versions of the B747SR were built for the Japan domestic market. Maximum seating was 490 - 560.
Capt Fathom is offline  
Old 12th Nov 2019, 11:12
  #16 (permalink)  
 
Join Date: Jun 2001
Location: OZ
Posts: 954
About the LED retraction during reverse thrust - it was really a legacy thing from when the hot stream reversers existed and all this hot air could blow on to the LEDs and entrain stuff to damage them. Fan reversers are actually in front of the LEDs close to their engines but why bugger around with certification stuff? Just leave well enough alone.
mustafagander is offline  
Old 13th Nov 2019, 00:47
  #17 (permalink)  
Thread Starter
 
Join Date: Jun 2019
Location: Tana
Posts: 0
Originally Posted by Capt Fathom View Post
Several versions of the B747SR were built for the Japan domestic market. Maximum seating was 490 - 560.
What about 747-400D? I vaguely remember reading about Boeing offering a configuration to sit 600+ passengers. Did any Japanese airline took it?
UltraFan is online now  
Old 13th Nov 2019, 13:32
  #18 (permalink)  
 
Join Date: Jan 2008
Location: Reading, UK
Posts: 10,982
The 747-400D exit limit was 660 pax, but the only two operators of the variant (JAL and ANA, with 19 aircraft in total) flew them with 565 and 568 seats respectively.

I've seen Boeing docs showing a suggested 630-seat all-Y configuration.
DaveReidUK is online now  
Old 13th Nov 2019, 18:51
  #19 (permalink)  
Thread Starter
 
Join Date: Jun 2019
Location: Tana
Posts: 0
Ah, that's where this number came from! Well, still, that's a lot of people for four rafts that don't look too big to me.
UltraFan is online now  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.