highflyer9790
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Joined: Thu Jul 07, 2005 1:21 am

BA 747 Emergency Question

Tue Mar 13, 2007 8:48 am

Hello again all,

Dont be alarmed, its not breaking news! Im not trying to be dramatic, so here is what happened and im wondering if anyone has any ideas as to what it could be:

Some friends of mine were on a BA 747 flight from SIN to New Zealand when just after reaching cruising altitude upon departure from SIN, a burning smell was noticed in the cabin. As the smell got stronger, all of the F/As were called to the flightdeck. Shortly thereafter, the captain announced they would be making an emergency descent & landing into the nearest airport (Bali) due to a technical problem. the electricity in the cabin was then shut off (i dont think it was the usual cabin lights off for landing) and a quick descent was made. they were greeted at bali by firetrucks and EMS on both sides of the aircraft.

anyone have an idea as to what the problem could have been? electrical? engine or A/C related?

thanks!

highflyer

ps- What would an "emergency descent" intail? i know for a pressurization failure, its something like -8,000 fpm w/speedbrakes...so would this just be a faster than normal descent at maybe -3,000 to -4,000 fpm?
121
 
Tristarsteve
Posts: 3373
Joined: Tue Nov 22, 2005 11:04 pm

RE: BA 747 Emergency Question

Tue Mar 13, 2007 6:35 pm

One of the recirculation fans failed. This is a not uncommon occurance on B744 and B777. The fan bearings fail and smoke pours into the cabin.
They are being modified yet again with vibration meters and auto shut down system.
Time will tell if it works.
 
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Starlionblue
Posts: 17208
Joined: Fri Feb 27, 2004 9:54 pm

RE: BA 747 Emergency Question

Tue Mar 13, 2007 9:23 pm

Quoting HighFlyer9790 (Thread starter):

ps- What would an "emergency descent" intail?

This depends. As you mention, if pressurization is a problem or if there is an uncontrolled fire on board the descent will be brisk. If, on the other hand, you simply need to get down to the nearest airport, there is no point pointing the nose a the ground so dramatically. Unless the airport is right under you I suppose.  Wink
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
G-CIVP
Posts: 1468
Joined: Tue Mar 20, 2001 6:38 am

RE: BA 747 Emergency Question

Wed Mar 14, 2007 2:27 am

One minor point, BA009 goes into SYD, not New Zealand.
 
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Jetlagged
Posts: 2562
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RE: BA 747 Emergency Question

Wed Mar 14, 2007 7:24 am

Quoting Starlionblue (Reply 2):
Quoting HighFlyer9790 (Thread starter):

ps- What would an "emergency descent" intail?

This depends.

So that would be the "not quite such an emergency descent" procedure then?  Wink

With the possiblity of an electrical fire on board, I'd want to descend fairly rapidly.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
CoolGuy
Posts: 366
Joined: Tue Jan 18, 2005 8:13 am

RE: BA 747 Emergency Question

Wed Mar 14, 2007 8:51 am

I have no idea what the maximum capabilities of a 747 are. What's its greatest descent rate in an emergency? I once heard 6000fpm for another commercial aircraft.
 
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LHRBFSTrident
Posts: 555
Joined: Wed Nov 15, 2006 3:38 pm

RE: BA 747 Emergency Question

Wed Mar 14, 2007 12:53 pm

Quoting G-CIVP (Reply 3):
BA009 goes into SYD, not New Zealand.

...but years ago it went to AKL (and I mean decades ago - I think BA009 was the flight where all engine flamed out over Indonesia enroute to SYD and AKL - G-BDXH 747-236 c.1982.) I believe it retained that flight number through to the 90s when BA gave up AKL in favour of a QF codeshare connection through LAX...

and I think it may have also served CHC for the few years that station recieved BA service

original poster neglected to give us a date for this trip - could be a delayed question, you know, by a decade or so
 Wink
 
LAXspotter
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RE: BA 747 Emergency Question

Wed Mar 14, 2007 1:53 pm

All i know is anything faster than 3,500 ft on a 747 is really pushing it. Besides if somebody can find out at what Vertical speed youre weightless, it the point where you know thats its absurd to descend that way.
"Patriotism is the last refuge of the scoundrel" Samuel Johnson
 
Tristarsteve
Posts: 3373
Joined: Tue Nov 22, 2005 11:04 pm

RE: BA 747 Emergency Question

Wed Mar 14, 2007 2:58 pm

Quoting LAXspotter (Reply 7):
Besides if somebody can find out at what Vertical speed youre weightless,

Inside an aircraft at a constant vertical speed your weight is constant.
To achieve weightlessness you need a constant acceleration of 1g.
This is why astronaut training flights fly a parabolic profile.
 
rwessel
Posts: 2448
Joined: Tue Jan 16, 2007 3:47 pm

RE: BA 747 Emergency Question

Wed Mar 14, 2007 3:03 pm

Quoting LAXspotter (Reply 7):
All i know is anything faster than 3,500 ft on a 747 is really pushing it. Besides if somebody can find out at what Vertical speed youre weightless, it the point where you know thats its absurd to descend that way.


High vertical velocity does *not* cause weightlessness, but vertical acceleration (towards the center of the earth, anyway) can, if it's at the usual 32ft/s/s. IOW, you could be descending (or ascending) at a steady million feet per second, and you would be at exactly one G (you would also have a lovely, although brief, view of the airframe melting, but that's a different issue). OTOH, if you jumped from a stationary platform above the atmosphere, you would be immediately weightless (and starting from a vertical velocity of zero), but accelerating at 32/ft/s/s towards the earth, and you would remain weightless until something (the atmosphere, ground, etc.) interfered with that acceleration.

NASA’s famed “vomit comet” achieves weightlessness by flying a parabolic arc (in which the vertical acceleration is exactly, and constantly, 32ft/s/s). You’re weightless over the entire arc, from just after the (high G) pull-up, on the uphill, over the top and downhill segments, until the (high G) pull out at the end. At the start of the arc the vertical velocity is quite high (but headed up), at the top it’s zero, and at the end it’s quite high again, but this time headed down. Zero G all the way.

(edit: added vomit comet example)

[Edited 2007-03-14 08:11:05]
 
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Jetlagged
Posts: 2562
Joined: Sun Jan 23, 2005 3:00 pm

RE: BA 747 Emergency Question

Wed Mar 14, 2007 9:59 pm

Quoting LAXspotter (Reply 7):
All i know is anything faster than 3,500 ft on a 747 is really pushing it. Besides if somebody can find out at what Vertical speed youre weightless, it the point where you know thats its absurd to descend that way.

The crew wouldn't set a vertical speed, they would keep airspeed at VMO with pitch (engines at idle of course). The resultant vertical speed will then depend on drag (i.e. whether you have the speedbrake deployed or the gear extended). The aircraft flight manual will give vertical speed for the conditions. There isn't a maximum vertical speed as such.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
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Starlionblue
Posts: 17208
Joined: Fri Feb 27, 2004 9:54 pm

RE: BA 747 Emergency Question

Wed Mar 14, 2007 10:09 pm

Quoting Jetlagged (Reply 10):
There isn't a maximum vertical speed as such.

Not in controlled flight no.  Wink
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
mandala499
Posts: 6460
Joined: Wed Aug 29, 2001 8:47 pm

RE: BA 747 Emergency Question

Mon Mar 26, 2007 2:30 am

Speedbird009 and another mishap over Indonesia...
Both cases involved "smoke and smells" in the cabin/cockpit
Both cases flights diverted to Indonesia (Halim in the 80s, Bali recently)
Both declared may-days
Both had ATC misunderstanding the situation initially (though the recent one I heard was a lot worse in terms of misunderstanding).

*forget conspiring on coincidences...*

Now, the recent Speedbird 009 required the mayday to be relayed to the ATC in Ujung Radio... (not the best of ATC centers to have an emergency in, even by our local standards)... The report I received was that the aircraft had past Bali when it happened. If it was just after reaching cruise, it would have been better to return to Singapore, or diverted to Jakarta or Surabaya... not Bali... And west of Bali, the ATC is reasonably good (Jakarta and Bali Sectors...), but Ujung Sectors... well... let's just say many complaints have been aired!

Mandala499
When losing situational awareness, pray Cumulus Granitus isn't nearby !

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