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

Fuel inbalance and engine separation.

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

Fuel inbalance and engine separation.

Old 11th Sep 2004, 11:33
  #1 (permalink)  
Thread Starter
 
Join Date: Dec 2003
Location: Dubai
Posts: 212
Likes: 0
Received 0 Likes on 0 Posts
Fuel inbalance and engine separation.

Anybody that has guidelines related to this combination of events?

How do you combine both checklists accurately?
Cap 56 is offline  
Old 11th Sep 2004, 12:03
  #2 (permalink)  
 
Join Date: Mar 2002
Location: Florida
Posts: 4,569
Likes: 0
Received 1 Like on 1 Post
Cap 56

I may be missing your real question here but for starters:

How would you know that you had a separation?

The checklists are based on likely known scenarios.

Does this reference add anything to your question?

see chaps 3 & 4

http://fromtheflightdeck.com/Stories/turbofan/
lomapaseo is offline  
Old 11th Sep 2004, 12:15
  #3 (permalink)  
 
Join Date: May 2002
Location: Australia
Posts: 2,242
Likes: 0
Received 0 Likes on 0 Posts
On the Boeings that I have flown the check list is called; "Engine Fire, Severe damage or Separation" and is carried out as soon as possible after achieving/when at a safe height. In the case of a separation you are likely to get a Bleed Duct leak message and this will require prompt attention too.

A fuel imbalance checklist is a separate checklist and would be carried out when the fuel imbalance became obvious or EICAS messages called for it.

Normal policy is not to try and combine checklists, it is the Captains job to decide the priorities and call for the appropriate lists in due turn, each to be treated as a separate entity.

Hope this helps.
BlueEagle is offline  
Old 11th Sep 2004, 12:33
  #4 (permalink)  
Thread Starter
 
Join Date: Dec 2003
Location: Dubai
Posts: 212
Likes: 0
Received 0 Likes on 0 Posts
I understand that the fuel unbalance is used to correct an unbalance in weight. In other words shift the CG back to be were it belongs so you do not run out of aileron control.

Surely if an engine (I am sure the equivalent of several tons) drops from the wing you will notice it in the flight controls, engine indications have either disappeared or read zero, etc….

In order to rebalance the overall weight (engines and fuel) you may not want to fall in the trap of the Fuel Unbalance EICAS message and blindly INCREASE the unbalance even more?

What does common sense tell you in this case ?

To be honest, I have made up my mind on this one many years ago, I am just checking by opening this tread if I have not overlooked something.

lomapaseo

Thanks, interesting link.
Cap 56 is offline  
Old 11th Sep 2004, 13:48
  #5 (permalink)  

Mach 3
 
Join Date: Aug 1998
Location: Stratosphere
Posts: 622
Likes: 0
Received 0 Likes on 0 Posts
Lateral thinking tells me that if a donk drops off, it won't go without allowing a lot of fuel to go in the same direction.

I suppose it depends on the precise nature of the separation and the location of the ENG FSOV's.

Whereupon I imagine the most important consideration is the position of the XFEED valve.

From personal experience it is a highly uncomfortable sensation when one realises, inspite of both donks turning, a significant fuel imbalance exists.

SR71 is offline  
Old 11th Sep 2004, 13:58
  #6 (permalink)  
 
Join Date: May 2002
Location: Australia
Posts: 2,242
Likes: 0
Received 0 Likes on 0 Posts
When an engine separation occurs, because it is a physical breaking of various lines and wires etc. you can expect to get many warnings, some, like a fire warning, are likely to be spurious as there is no engine and therefore probably no fire.

As there is no engine to consume fuel, fuel consumption will go down if the fuel wing valve is still able to be closed. Just how and when an imbalance may occur on a 747 will depend on your fuel configuration, are you running off the centre wing tank or the wing tanks? The captain and his crew will evaluate the situation and set up the fuel panel accordingly.
Bear in mind that after an engine fire, severe damage or separation you will only be looking for somewhere to land as soon as possible, so, providing fuel is not venting uncontrolled to atmosphere, it is highly unlikely that a serious imbalance will have time to develop before you are back on the ground.

Sorry if this sounds a bit simplistic CAP56 but from your posts I have assumed that you are not a pilot, particularly when you make a statement to the effect that; "I have made up my mind on this one many years ago"!
There are so many variables that you can never, safely, "Make up your Mind" If you told us where you are in aviation it would make answering you a little easier, perhaps!
BlueEagle is offline  
Old 11th Sep 2004, 14:53
  #7 (permalink)  
JEP
 
Join Date: Apr 2002
Location: Denmark
Posts: 110
Likes: 0
Received 0 Likes on 0 Posts
Back in 1992 a B707 lost both its engines on the right wing over France.

Somehow the plane remained flyable.

The plane was written off due to damages during emergency landing and fire, but everybody survived. If was a freight plane, but anyway.

Amazing job done by the crew.
JEP is offline  
Old 11th Sep 2004, 17:20
  #8 (permalink)  

Aviator Extraordinaire
 
Join Date: May 2000
Location: Oklahoma City, Oklahoma USA
Age: 76
Posts: 2,394
Likes: 0
Received 0 Likes on 0 Posts
I also remember a 707 in California, in the 1970s, that lost (as in fell off) the number 4 engine AND all of the wing outboard of the number 4 engine mount. This guy not only had the loss of thrust to contend with but also a massive instantaneous fuel imbalance. At first he was going to ditch the aircraft near the beach, but after a few minutes of flying he discovered that he more control of the aircraft than he first thought and successfully landed the airplane at an Air Force Base.

I believe it was a Pan Am 707, but in any case it was a hell of a job of flying.
con-pilot is offline  
Old 11th Sep 2004, 18:24
  #9 (permalink)  
 
Join Date: Aug 2001
Location: Europe-the sunshine side
Posts: 755
Likes: 0
Received 0 Likes on 0 Posts
in case of separation,one important indication (737) is FAULT of the fire detection system.This is unlikely to apear in case of engine fire or severe damage.You'll have to land at the nearest airport,so not much fuel to be used further on .(around 200-400 kgs maybe,depending where this airport is)
so,you'll do the engine separation checklist,then if necessary ,fuel balance check.
alexban is offline  
Old 11th Sep 2004, 23:34
  #10 (permalink)  
 
Join Date: Feb 2000
Location: CYZV
Age: 77
Posts: 1,256
Likes: 0
Received 1 Like on 1 Post
Connie the accident you mention happened in 1965. There's a brief report on this page. It's the fourteenth item from the top of the page. See also what happened to the aircraft PanAm sent to pick up the pax.
pigboat is offline  
Old 12th Sep 2004, 09:56
  #11 (permalink)  
 
Join Date: Jun 2001
Location: FNQ ... It's Permanent!
Posts: 4,290
Received 167 Likes on 85 Posts
I recall some time ago a discussion re fuel imbalance in the B767. Boeing advice was that the aircraft was controllable with one wing tank full and the other tank empty. ie. 18 ton imbalance.
Maybe someone on the 767 can try this next time they are in the sim!
Capt Fathom is offline  
Old 12th Sep 2004, 15:46
  #12 (permalink)  

Aviator Extraordinaire
 
Join Date: May 2000
Location: Oklahoma City, Oklahoma USA
Age: 76
Posts: 2,394
Likes: 0
Received 0 Likes on 0 Posts
That's the one pigboat, I knew it was a long time ago.

Thanks!
con-pilot is offline  
Old 12th Sep 2004, 23:44
  #13 (permalink)  
 
Join Date: Mar 2002
Location: Florida
Posts: 4,569
Likes: 0
Received 1 Like on 1 Post
I also remember a 707 in California, in the 1970s, that lost (as in fell off) the number 4 engine AND all of the wing outboard of the number 4 engine mount. This guy not only had the loss of thrust to contend with but also a massive instantaneous fuel imbalance. At first he was going to ditch the aircraft near the beach, but after a few minutes of flying he discovered that he more control of the aircraft than he first thought and successfully landed the airplane at an Air Force Base.

I believe it was a Pan Am 707, but in any case it was a hell of a job of flying.
You probably mean this one

http://images.prosperpoint.com/image...113295-231.jpg
lomapaseo is offline  
Old 13th Sep 2004, 01:55
  #14 (permalink)  

Aviator Extraordinaire
 
Join Date: May 2000
Location: Oklahoma City, Oklahoma USA
Age: 76
Posts: 2,394
Likes: 0
Received 0 Likes on 0 Posts
Yup, again a hell of a job of flying. Anybody know how to find out the names of the flight crew? Their names need to be put on the list in jet blast on Best Pilots."
con-pilot is offline  
Old 13th Sep 2004, 15:53
  #15 (permalink)  
 
Join Date: Jan 2004
Location: LPPT
Age: 58
Posts: 431
Likes: 0
Received 0 Likes on 0 Posts
lomapaseo, thanks for the link.
GearDown&Locked is offline  

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

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