Qantas B744 Total electrical failure?
So here we have two recent News reports (my bolding)
I am quite interested in the question about sic. being either a design fault or a maintenance issue."
Obviously things break inside the cabins and this must be allowed for in the design of the aircraft, shielding, redundancy, etc.
From the pages of posts preceding this I still can't assess the degree of compliance with good design practice in this regard.
Qantas defends safety record as it probes jet's power loss
Qantas defended its safety record today as the airline investigated a dramatic loss of power in a jumbo on landing approach to Bangkok.
The B747-400 aircraft, en route from London on Monday with more than 300 people on board, landed safely after automatically reverting to standby battery power.
The power loss occurred after a cracked drip tray above electrical equipment let water enter an electrical bay where it caused several components to malfunction, Qantas says.
Qantas Executive General Manager John Borghetti has dismissed as "unhelpful" speculation by engineers, pilots, commentators and airline union officials about whether the power loss could have been disastrous if it happened further out over sea.
"Regardless of some of the more colourful claims being made about Qantas engineering standards, the truth is that Qantas has one of the world's leading engineering operations," Mr Borghetti said in a statement.
"As always, safety is our prime concern.
"We stand by our 87-year reputation for operational excellence and will never compromise our high standards."
The airline was investigating the "highly unusual incident" with manufacturer Boeing and the Australian Transport Safety Bureau, he said.
Boeing also issued a statement slamming the widespread speculation.
"Boeing and Qantas enjoy a long, successful history of 747 operation to the very highest standards the public expects of us, and the safety of those who fly on our airplanes is paramount," it said.
Qantas says it has checked the systems and equipment on all 30 of its B747-400 aircraft and the entire fleet had been cleared to fly.
The airline's engineers had planned industrial action over an unrelated pay dispute today but this was yesterday delayed until February.
The Australian Licensed Aircraft Engineers' Association is seeking a five per cent pay rise for up to 1,700 engineers nationwide, but the airline has offered only a three per cent increase.
AAP
Qantas defended its safety record today as the airline investigated a dramatic loss of power in a jumbo on landing approach to Bangkok.
The B747-400 aircraft, en route from London on Monday with more than 300 people on board, landed safely after automatically reverting to standby battery power.
The power loss occurred after a cracked drip tray above electrical equipment let water enter an electrical bay where it caused several components to malfunction, Qantas says.
Qantas Executive General Manager John Borghetti has dismissed as "unhelpful" speculation by engineers, pilots, commentators and airline union officials about whether the power loss could have been disastrous if it happened further out over sea.
"Regardless of some of the more colourful claims being made about Qantas engineering standards, the truth is that Qantas has one of the world's leading engineering operations," Mr Borghetti said in a statement.
"As always, safety is our prime concern.
"We stand by our 87-year reputation for operational excellence and will never compromise our high standards."
The airline was investigating the "highly unusual incident" with manufacturer Boeing and the Australian Transport Safety Bureau, he said.
Boeing also issued a statement slamming the widespread speculation.
"Boeing and Qantas enjoy a long, successful history of 747 operation to the very highest standards the public expects of us, and the safety of those who fly on our airplanes is paramount," it said.
Qantas says it has checked the systems and equipment on all 30 of its B747-400 aircraft and the entire fleet had been cleared to fly.
The airline's engineers had planned industrial action over an unrelated pay dispute today but this was yesterday delayed until February.
The Australian Licensed Aircraft Engineers' Association is seeking a five per cent pay rise for up to 1,700 engineers nationwide, but the airline has offered only a three per cent increase.
AAP
Cracks found inside Qantas 747s
A fault with galley drip trays found on a number of Qantas planes may be a problem for ageing Boeing 747s around the world.
Earlier this week, water leaking from a cracked drip tray caused an electrical short on a Qantas 747 en route from London to Bangkok.
The pilot had to resort to a back-up battery system after the power failed on descent into the Thai airport.
Qantas has since assessed all of its planes and found cracks in the drip trays on up to six others.
Peter Gibson from the Civil Aviation Safety Authority says investigators have been in contact with the manufacturers.
He says investigations are continuing into whether it is a design fault or a maintenance issue.
"Well clearly there was a failure in the drip tray as well which allowed the water to get through," he said.
"If that hadn't have happened obviously the water wouldn't have entered into the electrical component and obviously Qantas and indeed the Civil Aviation Authority have been talking to the manufacturer of Boeing about this issue from day one."
http://www.abc.net.au/news/stories/2...section=justin
A fault with galley drip trays found on a number of Qantas planes may be a problem for ageing Boeing 747s around the world.
Earlier this week, water leaking from a cracked drip tray caused an electrical short on a Qantas 747 en route from London to Bangkok.
The pilot had to resort to a back-up battery system after the power failed on descent into the Thai airport.
Qantas has since assessed all of its planes and found cracks in the drip trays on up to six others.
Peter Gibson from the Civil Aviation Safety Authority says investigators have been in contact with the manufacturers.
He says investigations are continuing into whether it is a design fault or a maintenance issue.
"Well clearly there was a failure in the drip tray as well which allowed the water to get through," he said.
"If that hadn't have happened obviously the water wouldn't have entered into the electrical component and obviously Qantas and indeed the Civil Aviation Authority have been talking to the manufacturer of Boeing about this issue from day one."
http://www.abc.net.au/news/stories/2...section=justin
Obviously things break inside the cabins and this must be allowed for in the design of the aircraft, shielding, redundancy, etc.
From the pages of posts preceding this I still can't assess the degree of compliance with good design practice in this regard.
Pending Boeing's coming up with a proper roof for the electrical bits, perhaps we should add a Galley Drain Test to the FO's walkaround
I'm waiting for somebody to suggest wiring in a diesel generator through the ground power bus and routing a fuel line to it
I'm waiting for somebody to suggest wiring in a diesel generator through the ground power bus and routing a fuel line to it
Registered User **
Join Date: Dec 2007
Location: The Moorings
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
Obvious isn't it?
Between the ever thickening trees of the understandable angst of QF maintenance and CC who may lose their jobs, and the drivers who equally understandably are concerned re encountering and handling the same condition it appears few seem able to discern the primary problem woods.
Forget about fixing drip trays or ill designed drains etc - that's a sideshow.
Isn't the primary cause the very basic Boeing design flaw which saw multiple components intended to provide their much vaunted fail safe multiple redundancy features all co-located in the same bay?
Fail safe original design multiple redundancy features all eliminated at the stroke of a pen by some Boeing design engineer who thought it was a great idea to co-locate all of his safety feature and redundancy eggs into the same basket.
Eventually and inevitably, many years later Mr Murphy came calling and treated one and all of them an indigestible big drink.
How many other Boeings now flying or on the drawing board share this utterly foolish electrical design I wonder?
Hopefully not also Seattles "Electric Airplane".
AD's on the way anybody?
Forget about fixing drip trays or ill designed drains etc - that's a sideshow.
Isn't the primary cause the very basic Boeing design flaw which saw multiple components intended to provide their much vaunted fail safe multiple redundancy features all co-located in the same bay?
Fail safe original design multiple redundancy features all eliminated at the stroke of a pen by some Boeing design engineer who thought it was a great idea to co-locate all of his safety feature and redundancy eggs into the same basket.
Eventually and inevitably, many years later Mr Murphy came calling and treated one and all of them an indigestible big drink.
How many other Boeings now flying or on the drawing board share this utterly foolish electrical design I wonder?
Hopefully not also Seattles "Electric Airplane".
AD's on the way anybody?
More bang for your buck
Join Date: Nov 2005
Location: land of the clanger
Age: 82
Posts: 3,512
Likes: 0
Received 0 Likes
on
0 Posts
Isn't the primary cause the very basic Boeing design flaw which saw multiple components intended to provide their much vaunted fail safe multiple redundancy features all co-located in the same bay?
Where do you stop?
(I agree with you by the way)
Join Date: Dec 1998
Location: .
Posts: 2,997
Likes: 0
Received 0 Likes
on
0 Posts
Boeing design engineer who thought it was a great idea to co-locate all of his safety feature and redundancy eggs into the same basket.
I would say it did as designed, it landed safely, flaps/controls/gear etc all worked off stdby pwr and DC pwr as designed. Maybe that's why stdby pwr is checked on every daily check on the 744.
Let's not be too quick to paint this as a blame game on either maintenance or design.
If you believe it's a design screwup backed up by a screwup of the FARs as well then point me to the basic assumption that led to this. Because that's where there should be a golden nugget of a lesson learned for everybody.
If you believe it's a design screwup backed up by a screwup of the FARs as well then point me to the basic assumption that led to this. Because that's where there should be a golden nugget of a lesson learned for everybody.
More bang for your buck
Join Date: Nov 2005
Location: land of the clanger
Age: 82
Posts: 3,512
Likes: 0
Received 0 Likes
on
0 Posts
If you believe it's a design screwup backed up by a screwup of the FARs as well then point me to the basic assumption that led to this. Because that's where there should be a golden nugget of a lesson learned for everybody.
Behind all technical failures there is a human failure, be it design, implementation, inspection or the implementation of a technology without fully understanding it.
Join Date: Jun 2001
Location: UTC +8
Posts: 2,626
Likes: 0
Received 0 Likes
on
0 Posts
buggaluggs ". . . However, on a very dark moonless and stormy night, in IMC, and 3 hours from anywhere remotely resembling an airfield, it may be time to starting thinking outside the QRH.
Can it be done? Maybe , should it be done? Thats what the guy/girl in the front left seat gets paid to decide!"
Can it be done? Maybe , should it be done? Thats what the guy/girl in the front left seat gets paid to decide!"
Incidentally, I have found that my handheld GPS reception works best when placed at the lower rear window.
Join Date: Jan 2007
Location: San Jose
Posts: 727
Likes: 0
Received 0 Likes
on
0 Posts
RBF:
Emergency pedals on all seats in the first class cabin. In event of total electrical failure, all passengers to start pedalling furiously, encouraged by repeated announcements reminding them that they're the ones that will hit the ground first if they don't.
It rather sounds like some aircraft equipment/cable routeing is in need of serious review. Even if it's determined to be a maintenance issue with the drains, the mere fact that it can happen is a good reason for looking at a slight adjustment to things to make it less likely that all electrical buses can be taken out by a single problem. Ground-based stuff can suffer from the "common mode JCB fault" where supposedly-independent systems accidentally get put through the same duct or wrapped in the same bundle when they ought to be kept well apart, it appears that some aircraft have a similar problem.
I'm waiting for somebody to suggest wiring in a diesel generator through the ground power bus and routing a fuel line to it
It rather sounds like some aircraft equipment/cable routeing is in need of serious review. Even if it's determined to be a maintenance issue with the drains, the mere fact that it can happen is a good reason for looking at a slight adjustment to things to make it less likely that all electrical buses can be taken out by a single problem. Ground-based stuff can suffer from the "common mode JCB fault" where supposedly-independent systems accidentally get put through the same duct or wrapped in the same bundle when they ought to be kept well apart, it appears that some aircraft have a similar problem.
Join Date: Apr 2000
Location: Oz
Posts: 754
Likes: 0
Received 0 Likes
on
0 Posts
Oh great. Now we have our illustrious General Manager John Borghetti saying that speculation about would might've happened in different circumstances is unhelpful.
The same Borghetti who walked into a meeting with junior managers a while ago (according to one who was there) and stated: "If I hear any of you say one bad word about this company, I'll sack you. Now, what is the first item on the agenda?" (I can imagine the response: "Errr, well sir, everything is just fine and dandy. Fiiiiine and dandy sir!")
Speculation is what people do. Considering what might happen in other scenarios is also how people make design improvements or better contingency plans.
The same Borghetti who walked into a meeting with junior managers a while ago (according to one who was there) and stated: "If I hear any of you say one bad word about this company, I'll sack you. Now, what is the first item on the agenda?" (I can imagine the response: "Errr, well sir, everything is just fine and dandy. Fiiiiine and dandy sir!")
Speculation is what people do. Considering what might happen in other scenarios is also how people make design improvements or better contingency plans.
Join Date: Feb 2004
Location: Australia
Posts: 1,307
Likes: 0
Received 0 Likes
on
0 Posts
Assuming a situation in mid Pacific, for example: One technique would be to pull circuit breakers to ensure that the battery powers only the SAI [Standy Attitude Indicator], this way it could remain powered for several hours. The objective would be to fly attitude and to keep wings level. Upon reaching adequate VMC [visual meterological conditions] it could be turned off to save battery power for descent and landing.
A few random thoughts.
Do flight crews have enough information in their manuals to know which CB's to pull?
Would you descend to a breatheable altitude in case you ran out of power manually control the outflow valves? (Assuming fuel burn was not an issue).
You would need to avoid clouds to stop the pitot and static probes icing up (assuming you could see them on, say, a moonless night with no Wx Radar and your windows fogged up?
). Descending to a lower altitude might also help with anti-icing(?)I would imagine that on 744's with Multi-Mode Receivers, you could periodically set the breakers for the Left MMR and the Left FMC/CDU to check your GPS position (noting that there is a certain time period for the GPS system to reacquire the satellites after switch-on). There would be no need for a handheld unit (with a bit of improvisation).
Would you turn off both IRU's? You would lose IRU navigation capabilities and your ND Map....but would this be such a bad thing? The IRU's can at least be switched on again as a back up for the Standby Horizon.
I had a quick look at the 744 wiring schematics and it seems like it may be possible to start the APU inflight by pulling selected Air-Ground System CB's, but it would be immensely risky (and probably wouldn't have worked in this particular galley overflow scenario). One of the risks is the large current draw from the APU Battery (this would be supplying power to the IRU's at the time).
Comments welcome (I promise not to bash my head against a brick wall this time).
Cheers.
NSEU.
Join Date: Jan 2005
Location: Sydney, Australia
Posts: 63
Likes: 0
Received 0 Likes
on
0 Posts
Do flight crews have enough information in their manuals to know which CB's to pull?
Would you descend to a breatheable altitude in case you ran out of power manually control the outflow valves? (Assuming fuel burn was not an issue).
Every situation will be different. If you have a lot of gas and a set of airports within a couple of hours, and LSALT is less than 10,000, yes, getting down may be the go. Even across the Pacific that'd be ok - get down and divert to one of the islands... if you can find it. (a hand held GPS plus booster antenna really could save the day. I've seen guys playing with these things on the flight deck and maybe it's time to get one myself!). Elsewhere, say across the Indian inbound to Perth - no options to lob into an airport short of Perth - so you'll have to stay at altitude.
I don't want to comment on the rest of your questions at this point. It's Saturday and I need to go to the beach! And they are all very problematic issues. Perhaps a lot of these ideas/strategies will be addressed in the aftermath to give crews more insight on what options are available. Now that the impossible has actually happened, HOPEFULLY there will be much greater system info provided. But, sadly, I won't be hiding my breath.
Last edited by Jay Arr; 12th Jan 2008 at 00:10.
Join Date: Mar 2007
Location: Australia
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
If this electrical failure occured in a twin engined commercial jet with, for example, ETOPS of 180 minutes would there have to be 180 minutes of battery charge available?
Cheers to all - my first post
Cheers to all - my first post
Join Date: Feb 2004
Location: Australia
Posts: 1,307
Likes: 0
Received 0 Likes
on
0 Posts
However, you may need to deploy the masks immediately - there'd be electrics involved in deploying them and presumably also in the sensors that eventually detect the cabin altitude has increased. "
"As for the outflow valves - would they fail closed or open? Don't know. Closed - your depress problem will be delayed. If packs stop and outflow valves failed closed, provided you've got the masks deployed I think you could stay at altitude for some time."
But, sadly, I won't be hiding my breath.
Cheers.
NSEU
Join Date: Mar 2002
Location: Oz
Posts: 381
Likes: 0
Received 0 Likes
on
0 Posts
The same Borghetti who walked into a meeting with junior managers a while ago (according to one who was there) and stated: "If I hear any of you say one bad word about this company, I'll sack you. Now, what is the first item on the agenda?" (I can imagine the response: "Errr, well sir, everything is just fine and dandy. Fiiiiine and dandy sir!")
Sadly, it is a style, which represents desperation and disorganisation, when leaders have to resort to threats to manage their employees.
Isn't there a name for this act?
I wondered about the redundancy of the 744 electrical systems while on the course. The 747s electrical system is similar, in fact almost identical to the VC10's, the aircraft I flew prior to the 744. This isn't by accident - it happened because the VC10s designers were poached by Boeing when they were made redundant by BAC once design of the VC10 was completed. The one big difference is that the VC10 had a RAT which would power the essential busses and half the power flying controls - the VC10 has electrically powered Flight controls which is why the RAT was installed.
However, with any system where generators are paralleled, there is a risk. The Bus Tie Breakers (BTBs) should trip, isolating the generators if a bus fault is detected. However, this doesn't always work and I have seen on one occasion, a bus fault trip two generators. If the Split System Breaker (SSB) is closed, whether intentionally or by another fault, the problem can be tranferred to both synchronus busses thus transferring the fault to all generators. It shouldn't happen, but quite clearly - it can!
I subsequently flew the 747 Classic which had better redundancy through some clever switchery by the FE. But who on earth thought of putting the batteries on the flight deck? My company had a nasty incident with a thermal runaway of a Ni Cad battery which filled the flight deck with a copious volume of noxious gas.
Water causing problems in the electrical bay of the 747 is a relatively common fault, whether it comes from the galley or a open L2 door in the rain. I've seen it a few times.
I remeber looking at the scenario of a total electric failure half way across the Atlantic in the sim, my company was reasonably concerned with the remote possibility of this scenario to do this. If there are enough visual references to continue to fly the aircraft with the batteries off, it's manageable. But not nice!
However, with any system where generators are paralleled, there is a risk. The Bus Tie Breakers (BTBs) should trip, isolating the generators if a bus fault is detected. However, this doesn't always work and I have seen on one occasion, a bus fault trip two generators. If the Split System Breaker (SSB) is closed, whether intentionally or by another fault, the problem can be tranferred to both synchronus busses thus transferring the fault to all generators. It shouldn't happen, but quite clearly - it can!
I subsequently flew the 747 Classic which had better redundancy through some clever switchery by the FE. But who on earth thought of putting the batteries on the flight deck? My company had a nasty incident with a thermal runaway of a Ni Cad battery which filled the flight deck with a copious volume of noxious gas.
Water causing problems in the electrical bay of the 747 is a relatively common fault, whether it comes from the galley or a open L2 door in the rain. I've seen it a few times.
I remeber looking at the scenario of a total electric failure half way across the Atlantic in the sim, my company was reasonably concerned with the remote possibility of this scenario to do this. If there are enough visual references to continue to fly the aircraft with the batteries off, it's manageable. But not nice!
Join Date: Jul 2003
Location: Australia
Posts: 157
Likes: 0
Received 0 Likes
on
0 Posts
t may well be that that cause could only be seen with hind-sight, or it may be that if a proper risk assessment had been carried out then the event would have been foreseen.
Ask your self why commercial aircraft don't fly with Huge Parachutes so they can safely settle back to earth if all engines/ electric power fails? Because the size, weight, expense outweighs the risk. It is acceptable to argue one hull loss over 40 years of operation with many, many millions of passenger miles without incident is a sound economic decision. There are many similar decisions being made every day and yes aircraft are going to crash but sometimes it has already been calculated and accepted.
Join Date: May 2003
Location: Maastricht
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
I'm not a pilot (just a humble ATCO), but on engine start-up at SIN on the 5th Jan on QF10 to MEL, there was some kind of fault. All the electrical power went and we were left in darkness briefly before the emergency lights came on. A few seconds later the pilot told us that the APU had just died, and that we would have to be towed back to the gate and have the ground power attached. Ten mins later we pushed back again and they managed to start the engines OK.
This probably has no relation to the incident at BKK, but I was just curious. Anybody?
This probably has no relation to the incident at BKK, but I was just curious. Anybody?