Polish LOT 767 wheels up landing
4whisky wrote...
CB...
"There are some gossips from technicians that the alternate LG system circiuit breaker was found popped out on ground. Looks bad for the crew then..."
What if the CB had popped because of a malfunction and could not be reset?
With all the time they had available to them in the crossing and prior to landing while burning excess fuel, I find it hard to believe a single CB related to the emergency gear lowering process was overlooked especially after we know others outside the cockpit crew (maintenance) were involved in the trouble shooting.
I guess time will tell when the investigation starts coming out with some of its findings.
CB...
"There are some gossips from technicians that the alternate LG system circiuit breaker was found popped out on ground. Looks bad for the crew then..."
What if the CB had popped because of a malfunction and could not be reset?
With all the time they had available to them in the crossing and prior to landing while burning excess fuel, I find it hard to believe a single CB related to the emergency gear lowering process was overlooked especially after we know others outside the cockpit crew (maintenance) were involved in the trouble shooting.
I guess time will tell when the investigation starts coming out with some of its findings.
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Greetings to All !
This is my first post and I have my first question already
Am I correct in assuming that with "C" hydraulic system "out", only one autopilot (left) remains operative?
This is my first post and I have my first question already
Am I correct in assuming that with "C" hydraulic system "out", only one autopilot (left) remains operative?
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Quick question from an SLF? In that last vid I noticed the slides from the aft doors were at a very shallow angle and difficult (it looked like) to slide down. Got me wondering if there could be scenarios in which the slides are an obstacle to evac - or are they solid enough that they can be walked (run) along as well as slid down?
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Quick question from an SLF? In that last vid I noticed the slides from the aft doors were at a very shallow angle and difficult (it looked like) to slide down. Got me wondering if there could be scenarios in which the slides are an obstacle to evac - or are they solid enough that they can be walked (run) along as well as slid down?
For example on the B744, if the aircraft tips on its tail, then doors 1 would not be used in an evacuation (too steep). In a belly landing, all doors would be useable, but doors 3 (overwing) would be selected to manual (no slide deployment) and people would be evacuated onto the wing - otherwise the slides at door 3 and 4 would meet.
Cabin crew are trained in these scenarios, but would also visually check outside for hazards prior to opening the door, or redirecting passengers to another exit.
But yes, where a slide is too shallow to "slide" on, they are rigid enough to walk on, just as they would be when used as rafts.
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What if the CB had popped because of a malfunction and could not be reset?
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I believe you can do that with any circuit breaker. You can also put a penny in your household fusebox, if you have one of those old-fashioned things, instead of a screw-in glass fuse...
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Not sure about the 767, but on the 727 I can hold a CB closed if I desperately need the associated equipment to operate.
I might try an extra reset or two though.
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Obviously it depends on the situation, say you lose your generator fields/generators for whatever reason and desperately need to close a field breaker (IMC with the battery depleted, for instance) you could hold the gen field breaker closed and restore essential power at least and potentially all 3 AC busses (example is 727 specific).
As far as the landing gear is concerned I'm not sure how long the cycle to release uplocks would be on the 767 with the ALT system, and I'm not even sure that a CB was an issue here. Just pointing out an option that is available if the situation calls for it.
Theoretically, let's say the weather was not clear and calm like on the day of this incident (and diverting to another field with good conditions was not an option). Holding the CB would be taboo on a good day to some, but on a bad day one might want to seriously consider holding that CB in long enough to extend the gear. And, again, not sure that a CB was at issue here.
As far as the landing gear is concerned I'm not sure how long the cycle to release uplocks would be on the 767 with the ALT system, and I'm not even sure that a CB was an issue here. Just pointing out an option that is available if the situation calls for it.
Theoretically, let's say the weather was not clear and calm like on the day of this incident (and diverting to another field with good conditions was not an option). Holding the CB would be taboo on a good day to some, but on a bad day one might want to seriously consider holding that CB in long enough to extend the gear. And, again, not sure that a CB was at issue here.
Last edited by aviatorhi; 6th Nov 2011 at 01:16.
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I worked on the 1st 38 767 at the Boeing Everett plant (1981-1983). You are correct. The 1st 767 had a 3 a Flt Engr. At that time, there was a floor panel behind the Flt Engr. He could pop open the latches and 3 telescoping levers were there to Alternate Extend. But with the design change to 2 man Flt Deck, they removed the levers and installed a DC motor to drive all 3 cables.
For alternate gear extension, the guarded alternate extension switch on the P3-1 panel energizes the electric actuator to the extend or retract position. In the extend mode, power from the 28 VDC Hot Battery Bus passes to the actuator when the alternate gear extension switch is positioned to extend and when the landing gear lever is not in the UP position. When the actuator has reached the full extend position, the extend limit switch will open breaking power to the actuator.
For alternate gear extension, the guarded alternate extension switch on the P3-1 panel energizes the electric actuator to the extend or retract position. In the extend mode, power from the 28 VDC Hot Battery Bus passes to the actuator when the alternate gear extension switch is positioned to extend and when the landing gear lever is not in the UP position. When the actuator has reached the full extend position, the extend limit switch will open breaking power to the actuator.
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I hope you all understand that if the CB has tripped it has done so for a reason.
All this talk of holding it in scares me a bit. I am damn sure it doesn't permit that in the QRH. One go at resetting and then end it.
All this talk of holding it in scares me a bit. I am damn sure it doesn't permit that in the QRH. One go at resetting and then end it.
I hope you all understand that if the CB has tripped it has done so for a reason.
All this talk of holding it in scares me a bit. I am damn sure it doesn't permit that in the QRH. One go at resetting and then end it.
6th Nov 2011 05:03
All this talk of holding it in scares me a bit. I am damn sure it doesn't permit that in the QRH. One go at resetting and then end it.
6th Nov 2011 05:03
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Holding a CB in, or replacing a fuse with one of a (significantly) higher value is highly dangerous. The last time I saw it done, it resulted in the total destruction by fire of a Jaguar Mk X on its way to a car concourse when the wiring loom overheated and started a fire behind the dashboard which spread with terrifying speed. I was witness to this.
It is hard to imagine that professional flight crew would have held in a CB for more than a few seconds in a last ditch attempt to solve the problem, but desperation and fear are strange motivators. I hope the crew are exonerated from this.
It is hard to imagine that professional flight crew would have held in a CB for more than a few seconds in a last ditch attempt to solve the problem, but desperation and fear are strange motivators. I hope the crew are exonerated from this.
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LG extension
Hi, have been away for a while... Thanks for a very interesting discussion!
Just a quick question to those in the know: we know that Boeing/LOT technicians extended the LG from the cockpit. If they used ALTN LG extension then the landing gear doors (e.g. forward nose gear doors) would have remained in the open position. In this picture it is clearly in the closed position, which perhaps indicates the C HYD system was somehow pressurized and normal extension was used. Am I correct? Could someone correct me if I am not?
Just a quick question to those in the know: we know that Boeing/LOT technicians extended the LG from the cockpit. If they used ALTN LG extension then the landing gear doors (e.g. forward nose gear doors) would have remained in the open position. In this picture it is clearly in the closed position, which perhaps indicates the C HYD system was somehow pressurized and normal extension was used. Am I correct? Could someone correct me if I am not?
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Typical talk by souls who've never learned on "old iron", nor learned the finite properties of the various systems on board their craft.
Bet you don't know you can restore your ESS busses with "brute force" if necessary.
If the situation would have benefited from "overriding" the breakers for 5 seconds I'd take that over a belly landing any day of the week, month or year.
(RE: holding CBs)
Bet you don't know you can restore your ESS busses with "brute force" if necessary.
If the situation would have benefited from "overriding" the breakers for 5 seconds I'd take that over a belly landing any day of the week, month or year.
(RE: holding CBs)
Last edited by aviatorhi; 6th Nov 2011 at 19:22.
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Very true Capetonian and FireFlyBob, I was just pointing out what appears to be a Boeing design for holding in a couple of popping CB's that would be used in a desperation scenario. I assume that it is FAA approved and I thought it was interesting when I came across it.