Qantas B744 Total electrical failure?
ChristiaanJ;
The markers are quite clear, (and have been for a few years now), to "aviation eyes" and these notions are now being widely expressed here and in other venues. But they are not yet on any bean-counter's radar. Rarely are - know it, seen it, had it demonstrated in actual safety presentations - they have the MEGO* syndrome.
The trajectory and momentum of the present trends need an intervention. There are clear signals of a system under stress even from long-term well-established carriers with stellar reputations and histories. I think it is important to examine why and if it is a safety issue or not.
* my eyes glaze over
The markers are quite clear, (and have been for a few years now), to "aviation eyes" and these notions are now being widely expressed here and in other venues. But they are not yet on any bean-counter's radar. Rarely are - know it, seen it, had it demonstrated in actual safety presentations - they have the MEGO* syndrome.
The trajectory and momentum of the present trends need an intervention. There are clear signals of a system under stress even from long-term well-established carriers with stellar reputations and histories. I think it is important to examine why and if it is a safety issue or not.
* my eyes glaze over
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A concern that I have, being aircrew but not a pilot, is with the comment made that after landing a assymmetry situation existed when the flaps were retracted.
Does this mean the following.
1. When the flaps were lowered there could be a problem with the flaps deploying evenly on both sides.
2. Or that in the event that the airplane having to go around, that the flaps could not be moved from their current position.
My real concern, is that all the efforts made by the crew, is that the airplane, could be placed in more danger. If this situation came into to being whilst on the ground, why could it not occur in the air. Would this situation only exist on retraction, or could it occur on deployment.
Perhaps someone could clarify what happens under those circumstances.
Thanks
Col
Does this mean the following.
1. When the flaps were lowered there could be a problem with the flaps deploying evenly on both sides.
2. Or that in the event that the airplane having to go around, that the flaps could not be moved from their current position.
My real concern, is that all the efforts made by the crew, is that the airplane, could be placed in more danger. If this situation came into to being whilst on the ground, why could it not occur in the air. Would this situation only exist on retraction, or could it occur on deployment.
Perhaps someone could clarify what happens under those circumstances.
Thanks
Col
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Landing Gear:
Normal extension - electrically actuated, hydraulically powered.
Alternate extension - gravity powered but uplocks and gear doors are electrically released. What that means exactly, I'm not certain - whether you need an actual electrical signal to release the uplocks/doors, or, the absence of a current will cause uplocks/doors to release. I suspect the former.
All in all, in a totally dark aircraft I suspect the landing gear cannot be relied on.
Normal extension - electrically actuated, hydraulically powered.
Alternate extension - gravity powered but uplocks and gear doors are electrically released. What that means exactly, I'm not certain - whether you need an actual electrical signal to release the uplocks/doors, or, the absence of a current will cause uplocks/doors to release. I suspect the former.
All in all, in a totally dark aircraft I suspect the landing gear cannot be relied on.
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generally speaking the standby electrics should allow the pilot to perform an instrument approach at night in instrument conditions.
I would believe that the landing gear indications and actuation would properly work. ( also, I think that the alternate extension is an electric motor which pulls a cable to unlock the uplocks and allow gravity to do the rest)
I think even the pitot tubes/static system would have proper de/anti ice.
I'm sure there are some 744 guys out there who would be even more specific.
I would believe that the landing gear indications and actuation would properly work. ( also, I think that the alternate extension is an electric motor which pulls a cable to unlock the uplocks and allow gravity to do the rest)
I think even the pitot tubes/static system would have proper de/anti ice.
I'm sure there are some 744 guys out there who would be even more specific.
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sevenstrokeroll, sorry, I was really looking at the scenario where the mains system has totally gone and you've now used up your 30 mins of standby power (the batteries) ie, you're now totally powerless. Aside from being blind, mute, directionless and depressurising, I don't know if you've even got legs.
Pitot heat when on standby power: not 100% on this. My read of the 744 FCOM and QRH is that AC buses 1 and 4 power the Capt and F/O pitot heat respectively. And that if you are on standby power only these buses are not powered, only the main and APU standby buses are. The QF/Boeing manuals are typically not clear these days: statements such as "The main standby bus powers individual equipment items such as:" (my bold). The pitot heat is not included in these lists of equipment but such statements as above means it actually may be! However the QRH states you may have unreliable airspeed with AC buses 1 or 4 out....
So on standby power only - I'd be avoiding icing conditions!
Yep, I'm a 744 driver.
Pitot heat when on standby power: not 100% on this. My read of the 744 FCOM and QRH is that AC buses 1 and 4 power the Capt and F/O pitot heat respectively. And that if you are on standby power only these buses are not powered, only the main and APU standby buses are. The QF/Boeing manuals are typically not clear these days: statements such as "The main standby bus powers individual equipment items such as:" (my bold). The pitot heat is not included in these lists of equipment but such statements as above means it actually may be! However the QRH states you may have unreliable airspeed with AC buses 1 or 4 out....
So on standby power only - I'd be avoiding icing conditions!
Yep, I'm a 744 driver.
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Landing Gear:
Normal extension - electrically actuated, hydraulically powered.
All in all, in a totally dark aircraft I suspect the landing gear cannot be relied on.
WRONG WRONG WRONG WRONG....
744 Normal extension is mechanically activated, hydraulically powered. Mechanical cables run from the gear lever to the hydraulic selector valves in the wheel wells.
(Edit) Maybe you were thinking of the Lever Lock? This would be no impediment to retraction (just push the button) or extension (I believe the cam setup allows movement downwards without pushing the button)
Alternate extension requires Main Bus DC and AC power for control and power. Will not operate without main busses online.
Rgds.
NSEU
Normal extension - electrically actuated, hydraulically powered.
All in all, in a totally dark aircraft I suspect the landing gear cannot be relied on.
WRONG WRONG WRONG WRONG....
744 Normal extension is mechanically activated, hydraulically powered. Mechanical cables run from the gear lever to the hydraulic selector valves in the wheel wells.
(Edit) Maybe you were thinking of the Lever Lock? This would be no impediment to retraction (just push the button) or extension (I believe the cam setup allows movement downwards without pushing the button)
Alternate extension requires Main Bus DC and AC power for control and power. Will not operate without main busses online.
Rgds.
NSEU
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im not 100% on which mode the flaps would run when on standby power. if they were in primary electric or aux mode the flap assymmetry problem on retraction could very well have been caused due to the extremly slow operation of the flaps when being operated electrically.
in a missed approach situation with a fully powered aircraft you would most likely be well past the strip by the time the flaps could be retracted electrically.
keep in mind that the flaps are normally operated hydraulicaly (trailing edge) and pneumaticaly (leading edge) in normal operation.
in a missed approach situation with a fully powered aircraft you would most likely be well past the strip by the time the flaps could be retracted electrically.
keep in mind that the flaps are normally operated hydraulicaly (trailing edge) and pneumaticaly (leading edge) in normal operation.
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jay arr
sorry for any confusion.
My favorite plane could lose ALL electrics and still put the gear and flaps up and down...granted you might not have any gear position indicators other than looking through a floorboard periscope like device.
if you have lost everything...past the 30 minutes emergency...rotsa ruck...and keep your warranty card for a full refund!
sorry for any confusion.
My favorite plane could lose ALL electrics and still put the gear and flaps up and down...granted you might not have any gear position indicators other than looking through a floorboard periscope like device.
if you have lost everything...past the 30 minutes emergency...rotsa ruck...and keep your warranty card for a full refund!
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im not 100% on which mode the flaps would run when on standby power. if they were in primary electric or aux mode the flap assymmetry problem on retraction could very well have been caused due to the extremly slow operation of the flaps when being operated electrically.
in a missed approach situation with a fully powered aircraft you would most likely be well past the strip by the time the flaps could be retracted electrically.
keep in mind that the flaps are normally operated hydraulicaly (trailing edge) and pneumaticaly (leading edge) in normal operation.
In Primary electric or Altn electric, you're going to need main AC Bus power to run the electric drive motors. This means no electric flap deployement.
As I think I already explained, normal flap deployment requires FCU control. Battery and Standby power WILL provide all the necessary CONTROL electrics to run the flaps hydraulically.
This topic is becoming increasingly out of control because of misunderstandings about 744 systems. Please refer to your manuals before commenting!!!!!
Thanks.
NSEU
P.S. Yes, I understand your frustration about not being able to get a licence course.... Another consequence of budget cutbacks and lack of insight by managers.
in a missed approach situation with a fully powered aircraft you would most likely be well past the strip by the time the flaps could be retracted electrically.
keep in mind that the flaps are normally operated hydraulicaly (trailing edge) and pneumaticaly (leading edge) in normal operation.
In Primary electric or Altn electric, you're going to need main AC Bus power to run the electric drive motors. This means no electric flap deployement.
As I think I already explained, normal flap deployment requires FCU control. Battery and Standby power WILL provide all the necessary CONTROL electrics to run the flaps hydraulically.
This topic is becoming increasingly out of control because of misunderstandings about 744 systems. Please refer to your manuals before commenting!!!!!
Thanks.
NSEU
P.S. Yes, I understand your frustration about not being able to get a licence course.... Another consequence of budget cutbacks and lack of insight by managers.
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I'm a mere PPL flying your average steam powered GA stuff.. however, I believe there's a requirement that for IFR flight in such things you must have BOTH electric and vacuum driven gyro turn information - i.e. electric t/s, vacuum a/h etc.
Are there not any vacuum powered gyro instruments on a 747? Given a t/s OR a/h, an altimeter, (preferably) an ASI, functioning engines flight controls, flight at night, even after the battery dies should not mean everyone dies screaming surely?
Are there not any vacuum powered gyro instruments on a 747? Given a t/s OR a/h, an altimeter, (preferably) an ASI, functioning engines flight controls, flight at night, even after the battery dies should not mean everyone dies screaming surely?
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NSEU, you can "wrong wrong wrong wrong" and head pound all you like, mate! The fact is, my book is woefully sparse when it comes to detail and I'm only a 744 driver.... Give us a break. Perhaps you're right - I shouldn't have sinned, slipped up and erroneously uttered the words "electrically actuated" main extension, but nowhere in my book does it talk about cables from the lever to the hydraulic actuators ether. I'll head to church Sunday and flagellate myself for my transgression. You're probably right - I'm probably just thinking of the lever lock.
I was actually just trying to focus on what systems you don't have if you have zero electrics. My read is that you don't have alternate gear extension. Perhaps I'm overlooking the fact that normal system is ok? If so, don't do your head in over it. Man, I'm as in the dark as anyone when it comes to this improbable event. And it does highlight to me the lack of detail in QF/Boeing books these days. Don't expect to see that change though.
So you reckon/agree that if you're in a totally black jet (no mains or batteries left) the normal extension system will work but the alternate system won't?
What I really should do is just quit contributing to forums like this and question/discuss with the technical dept. At least there if you dare to make a mistake they say: "No no, blah blah..." and you go "Oh yes, that's right, blah blah...."
How does it go? Ah yes: 
I was actually just trying to focus on what systems you don't have if you have zero electrics. My read is that you don't have alternate gear extension. Perhaps I'm overlooking the fact that normal system is ok? If so, don't do your head in over it. Man, I'm as in the dark as anyone when it comes to this improbable event. And it does highlight to me the lack of detail in QF/Boeing books these days. Don't expect to see that change though.
So you reckon/agree that if you're in a totally black jet (no mains or batteries left) the normal extension system will work but the alternate system won't?
What I really should do is just quit contributing to forums like this and question/discuss with the technical dept. At least there if you dare to make a mistake they say: "No no, blah blah..." and you go "Oh yes, that's right, blah blah...."
How does it go? Ah yes:
Last edited by Jay Arr; 10th Jan 2008 at 23:44.
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"Are there not any vacuum powered gyro instruments on a 747? Given a t/s OR a/h, an altimeter, (preferably) an ASI, functioning engines flight controls, flight at night, even after the battery dies should not mean everyone dies screaming surely?"
No vacuum-powered devices on the 744.... unless you include Total Air Temp Probe ops (on ground/low speeds), cargo smoke detection ops, toilet flush, etc....
Standby Airspeed Indicator and Altimeter require no electrics (unless you include AC power for probe heat... not available on Standby Power... only main bus AC/DC). There is a vibrator in the altimeter which uses Main Bat Bus power (but when that fails, the captain can tap the instrument). As previously stated, one of the primary concerns on a "dead ship" would be lack of an attitude indicator (and things that go bump in the night... such as mountains).
Rgds.
NSEU.
No vacuum-powered devices on the 744.... unless you include Total Air Temp Probe ops (on ground/low speeds), cargo smoke detection ops, toilet flush, etc....
Standby Airspeed Indicator and Altimeter require no electrics (unless you include AC power for probe heat... not available on Standby Power... only main bus AC/DC). There is a vibrator in the altimeter which uses Main Bat Bus power (but when that fails, the captain can tap the instrument). As previously stated, one of the primary concerns on a "dead ship" would be lack of an attitude indicator (and things that go bump in the night... such as mountains).
Rgds.
NSEU.
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I got the concern over attitude indication, hence the question - was of the opinion that any one of t/c, t&s, or a horizon should be sufficient with asi&alt.
Somewhat gobsmacked that there's not one of the above on a vacuum/air driven system!
Somewhat gobsmacked that there's not one of the above on a vacuum/air driven system!
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Captain Al Haynes et. al
After following this thread for a few days now, you gotta wonder how Al Haynes and Denny someone "landed" their DC10 in Souix City. I realize total hydraulic failure is different then total electrical failure but the premise of "fail safe" just isn't there anymore. Its more "fail and try to resolve the matter even if it hasn't been practiced a million times in the sim, (V1 cuts, etc) and it all else fails, bend over, grab your ankles and kiss your 
goodbye.
Regards....
goodbye.Regards....
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BTW, NSEU, your statement "Alternate extension requires Main Bus DC and AC power for control and power" isn't exactly right either!
"Alternate gear extension is activated by pushing the Alternate Gear Extend switches. The gear uplocks and gear door latches are electrically released, allowing the gear to free fall. Gravity and airloads extend the gear and springs pull the downlocks into the locked position...." (Boeing B744 FCOM)
Electrically controlled, GRAVITY powered. (Perhaps you were thinking of alternate flaps?)
See you in church. We're all on the same side so I'll buy you a beer afterwards....
"Alternate gear extension is activated by pushing the Alternate Gear Extend switches. The gear uplocks and gear door latches are electrically released, allowing the gear to free fall. Gravity and airloads extend the gear and springs pull the downlocks into the locked position...." (Boeing B744 FCOM)
Electrically controlled, GRAVITY powered. (Perhaps you were thinking of alternate flaps?)
See you in church.
We're all on the same side so I'll buy you a beer afterwards....
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"Electrically controlled, GRAVITY powered. (Perhaps you were thinking of alternate flaps?)"
I wasn't... I was looking at the wiring schematics for Alternate Gear extension at the time. We just differ in definitions.
Control = the dc power which runs to the switch
Power= AC power which runs the electric drive motors which do the unlocking and repositioning of hydraulic valves (so they don't impede freefall)
Gravity was assumed
BTW, I was in the middle of a written apology to you (before I was interrupted by your second message)
Rgds.
NSEU
I wasn't... I was looking at the wiring schematics for Alternate Gear extension at the time. We just differ in definitions.
Control = the dc power which runs to the switch
Power= AC power which runs the electric drive motors which do the unlocking and repositioning of hydraulic valves (so they don't impede freefall)
Gravity was assumed
BTW, I was in the middle of a written apology to you (before I was interrupted by your second message)
Rgds.
NSEU
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Yes, one thing we can always rely on is gravity..........
Anyway, thanks for your thoughts and input, NSEU. Apologies if I was testy - everyone just assumes 744 drivers are all experts and without fault, and the reality is we're not (well, I'm not). A "benefit" of a near tragedy like this is that we all race for our books and notes, and bone up big-time. However as our Tech Manager has just posted on our internal chat-site, we do have to be very careful at this stage: a lot of info and mis-info goes flying around early on and it has to be treated accordingly. Attempting to start the APU in-flight is a good example.
Wiring schematics for alt gear extension? Wow, you've obviously got some good stuff - unlikely you're a 744 driver at the Roo then!
Cheers.
Anyway, thanks for your thoughts and input, NSEU. Apologies if I was testy - everyone just assumes 744 drivers are all experts and without fault, and the reality is we're not (well, I'm not). A "benefit" of a near tragedy like this is that we all race for our books and notes, and bone up big-time. However as our Tech Manager has just posted on our internal chat-site, we do have to be very careful at this stage: a lot of info and mis-info goes flying around early on and it has to be treated accordingly. Attempting to start the APU in-flight is a good example.
Wiring schematics for alt gear extension? Wow, you've obviously got some good stuff - unlikely you're a 744 driver at the Roo then!
Cheers.
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Qantas finds cracks, leaks in 747 fleet
Just came across this article,....
"Sydney (Agencies) - A fault with galley drip trays found on a number of Qantas planes may be a problem for ageing Boeing 747s around the world."
http://www.bangkokpost.com/breaking_....php?id=125028
"Sydney (Agencies) - A fault with galley drip trays found on a number of Qantas planes may be a problem for ageing Boeing 747s around the world."
http://www.bangkokpost.com/breaking_....php?id=125028