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BA 747 Emergency Question  
User currently offlineHighFlyer9790 From United States of America, joined Jul 2005, 1241 posts, RR: 0
Posted (7 years 4 months 2 weeks 2 days 6 hours ago) and read 6559 times:

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
12 replies: All unread, jump to last
 
User currently offlineTristarSteve From Sweden, joined Nov 2005, 3977 posts, RR: 34
Reply 1, posted (7 years 4 months 2 weeks 1 day 20 hours ago) and read 6477 times:

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.


User currently offlineStarlionblue From Greenland, joined Feb 2004, 16993 posts, RR: 67
Reply 2, posted (7 years 4 months 2 weeks 1 day 17 hours ago) and read 6442 times:

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."
User currently offlineG-CIVP From United Kingdom, joined Mar 2001, 1314 posts, RR: 10
Reply 3, posted (7 years 4 months 2 weeks 1 day 12 hours ago) and read 6374 times:

One minor point, BA009 goes into SYD, not New Zealand.

User currently offlineJetlagged From United Kingdom, joined Jan 2005, 2543 posts, RR: 24
Reply 4, posted (7 years 4 months 2 weeks 1 day 7 hours ago) and read 6262 times:

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.
User currently offlineCoolGuy From United States of America, joined Jan 2005, 414 posts, RR: 0
Reply 5, posted (7 years 4 months 2 weeks 1 day 6 hours ago) and read 6235 times:

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.

User currently offlineLHRBFSTrident From UK - Northern Ireland, joined Nov 2006, 655 posts, RR: 0
Reply 6, posted (7 years 4 months 2 weeks 1 day 2 hours ago) and read 6179 times:

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



Next up: LAX-LHR NZ002 Y SkyCouch! LHR-LAX NZ001 Y
User currently offlineLAXspotter From India, joined Jan 2007, 3650 posts, RR: 5
Reply 7, posted (7 years 4 months 2 weeks 1 day 1 hour ago) and read 6169 times:

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
User currently offlineTristarSteve From Sweden, joined Nov 2005, 3977 posts, RR: 34
Reply 8, posted (7 years 4 months 2 weeks 1 day ago) and read 6158 times:

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.


User currently offlineRwessel From United States of America, joined Jan 2007, 2311 posts, RR: 2
Reply 9, posted (7 years 4 months 2 weeks 1 day ago) and read 6157 times:
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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]

User currently offlineJetlagged From United Kingdom, joined Jan 2005, 2543 posts, RR: 24
Reply 10, posted (7 years 4 months 2 weeks 17 hours ago) and read 6098 times:

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.
User currently offlineStarlionblue From Greenland, joined Feb 2004, 16993 posts, RR: 67
Reply 11, posted (7 years 4 months 2 weeks 17 hours ago) and read 6094 times:

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."
User currently offlineMandala499 From Indonesia, joined Aug 2001, 6761 posts, RR: 76
Reply 12, posted (7 years 4 months 3 days 12 hours ago) and read 5680 times:

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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