Polish LOT 767 wheels up landing

[arc-en-ciel]

Landing Gear Alternate Extension
The alternate landing gear extension system uses an electric motor to trip the locking mechanism for each gear. Selecting DN on the ALTN GEAR EXTEND switch releases all door and gear uplocks. The landing gear free–fall to the down and locked position.

any more detailed info on this "alternate gear" thing?

[jamesbond6]

On subsequent pages there is an extended explanation. In order to use the alternate gear extension you are supposed to have the main lever in OFF position and move it to DOWN as a final step of this procedure. I wonder what would happen if it was in UP or DOWN position while putting the alternate switch to DOWN. Is it possible to lock some hydraulic valves in wrong position and disable the entire system, main or alternate, by f.e. leaving some hydraulic pressure?

[Airbubba]

Unless the authorities have recently relaxed the minimum system requirements for entering ETOPS areas, my many years of plowing twin Boeings and Airbuses across oceans left me with the distinct memory that the relevant QRH page left no doubt: three functioning hydraulic systems required to fly beyond sixty minutes of an adequate airport.

As for the A330 (I imagine the same general rule to 767 would apply), the loss of single hydraulic is not a cause for diversion unless you don't fit into destination. Neither does it warrant a change in ETOPS once airborne. There is no land ASAP at all. Your capability is degraded to CAT3A, yes, so why divert and land at possible worse off adequate (which might only be a VOR anyway) airfield when home base might be fine with sufficient reserves and runway/weather/you name it. All legal and fine, that's why we fly redundant aircraft, and it so happens the gear gets stuck and is only confirmed once the effort is made to lower it

Can anyone point to a relevant document to tell which of these opinions is correct? No matter what you decide these days, it will be second guessed unless you can point to it in the book (ask me how I know).

I have seen both views argued in ETOPS training over the years. Of course, I've also been told that you have to proceed to your ETOPS alternate if you lose an engine even if BIKF is CAVOK and nearby (I don't buy this one).

FAA AC 120-42B, the ETOPS Advisory Circular, has this somewhat generic guidance:

En Route.

(1) PIC Authority. No part of this AC is to be interpreted as reducing the PIC’s joint responsibility for determining that the flight can be safely conducted as planned before release. None of the guidance in this AC may be interpreted in any way to prejudice or limit the final authority and responsibility of the PIC for the safe operation of the airplane.

What this means these days is that we all know whom to blame for the decision to continue or divert.

[Starbear]

007

In order to use the alternate gear extension you are supposed to have the main lever in OFF position and move it to DOWN as a final step of this procedure. I wonder what would happen if it was in UP or DOWN position while putting the alternate switch to DOWN. Is it possible to lock some hydraulic valves in wrong position and disable the entire system, main or alternate, by f.e. leaving some hydraulic pressure?

In short, yes it is. To use ALTN Gear extension, the Landing Gear Lever should be in the OFF postion (hydraulics in a "runaround" type circuit) so if there is any hydraulic pressure available, gravity extension will merely push the fluid around the circuit. If the lever is left in the UP postion then its possible for fluid/pressure to be trapped in up circuit and so resist gravity extension.

The lever is placed to down after extension to satisfy indication and configuartion warning circuits (as well as GPWS alerts). Possibly even antiskid operation but not entirely sure of that as I can't remember.

[Escape Path]

@AirBubba

Well, actually you can certainly do ETOPS on the '76 with an FMC or a generator inop as I and another poster have observed. Did someone tell you otherwise?

Yes, I did read your post. But I reckon a generator or FMC failure is more critical to ETOPS operation than, in this case, the failure of one of three independent systems, which is what LJ60 was seemingly trying to portray.

Thanks for the clarification nevertheless

In my mind, the crew made the right decision; they had time in their hands to work out the failure and heading home they had also the choice of talking to their own staff. As some others had said, much better than having to do the same thing at an outlying station with much less support.

[Oilhead]

Air Bubba wrote - "I have seen both views argued in ETOPS training over the years. Of course, I've also been told that you have to proceed to your ETOPS alternate if you lose an engine even if BIKF is CAVOK and nearby (I don't buy this one)"

You are correct - alternates, whether destination or ETOPS, are for flight planning purposes only. There may be any one of several good reasons to not use a planned ETOPS alternate, that had been designated OK at point of dispatch or, of course, prior to ETOPS entry point, and go somewhere else. Hey, it may now be closed because someone else just did a wheels up a few minutes ago! As PIC you have both duty AND authority, including appropriate use of emergency authority, certainly under the US FAR's, to make the best decisions to protect the safety of aircraft and all aboard.

BTW, I fly the ETOPS 763, and I'm pretty sure the HMG is run from the centre system, in the event of AC power failure. To not have that back up "essential power" available, powering my basic flight instruments etc, would make me not want to wander too far at all from friendly surfaces, certainly within the (hopefully) 30 minutes battery life of aircraft.

[arc-en-ciel]

the question of entering ETOPS or not is paper story (they could have arrived from Hanoď it would be the same result).

the facts are :

1- Is it wise to leave an hydraulic system leaking for 7 hours ? (for my personal knowledge, I do not know the answer)

2 Why did this alternate gear did not work as designed ?!! (for the hundreds of other 767s in the world and the sake of their passengers and crew)

[Airbubba]

Yes, I did read your post. But I reckon a generator or FMC failure is more critical to ETOPS operation than, in this case, the failure of one of three independent systems, which is what LJ60 was seemingly trying to portray.

Sure, and some of this stuff is, to me anyway, somewhat non-intuitive. In the 'old days' you could always say you made a decision in the interest of safety and the chief pilot would back you up. Now, it is not so simple it seems.

I had a colleague initially hammered by the company for dumping fuel and diverting with a C HYD failure prior to a crossing. 'Why did you do that, you don't need the center system until you configure for landing?' they said. The FAA POI (Principal Operations Inspector) reviewed the incident and said it was the right decision, suddenly the company joined in commending the captain's wise actions.

I get my claim about 120 minute ETOPS dispatch with an IDG inop from the FAA MMEL 24-00-1 here:

FSIMS Document Viewer

Of course, the MEL is for dispatch, not enroute guidance but like I said, you are legal to go in this circumstance.

In my mind, the crew made the right decision; they had time in their hands to work out the failure and heading home they had also the choice of talking to their own staff. As some others had said, much better than having to do the same thing at an outlying station with much less support.

I sure can't fault that reasoning but with the FAA at least, you have to be very careful about mentioning economic or even logistic considerations when justifying a divert/continue decision from my observation.

[Jetjock330]

Airbuba,

I have tried to look around and find something as you had requested, but I am not sure it's a final answer to your question.

Can anyone point to a relevant document to tell which of these opinions is correct? No matter what you decide these days, it will be second guessed unless you can point to it in the book (ask me how I know).

Have a look at this general ETOPS from CAA CAP513, section 3.3

3.1
3.2

have the necessary information to make decisions on diversion at any point on the route.
Extended range operations are not permitted where any time limited system, that is essential for continued safe flight and landing has a minimum endurance that is less than the intended Rule Time, plus a 15 minute allowance for approach and landing at a suitable aerodrome, e.g. a cargo compartment fire suppression system.
If enhanced scheduled maintenance, replacement, and/or inspection are utilised to obtain type design approval for extended range operation, then the specified maintenance should be clearly identified in an appropriate approved maintenance manual and schedule.
Analysis of Failure Effects and Reliability1 General
The analysis and demonstration of system failure effects and reliability should be based on the maximum declared endurance of the aeroplane used in extended range operation.
Propulsion Systems

• a) An assessment of the propulsion systems reliability for particular airframe/engine combinations will be made in accordance with Appendix A.
• b) The analyses will review, in the context of extended range operations, the effects of operation with a single propulsion system, including probable damage that could result from failure of the first engine. Effects of failures, external conditions, or crew errors, that could jeopardise the operation of the remaining propulsion system under single power unit operating conditions, will be examined.

NOTE: Consideration should be given to any adverse effect of electrical failure on the aeroplane fuel supply system e.g. loss of fuel boost and transfer pumps.
Hydraulic Power and Flight Control Consideration of these systems may be combined, since many commercial aeroplanes have full hydraulically-powered controls. For aeroplanes with all primary flight controls hydraulically powered, evaluation of hydraulic system redundancy should include a determination of the ability to maintain continued safe flight and landing after the complete loss of any two hydraulic systems and either engine, unless it can be shown that such a combination of events is Extremely Improbable." unquote.

If safe flight cannot be continued safely, then a diversion is required, however, I believe safe flight can be completed as a single hydraulic failure is not an emergency or urgency.

[arc-en-ciel]

What bus supplies the electric motor ?

What is the frequency of the maintenance/check of this motor ?

[BN2A]

If a B747 or A340/380 lose one hydraulic system, how would that affect the situation?? Wouldn't be an ETOPS issue......

Just wondered...

[Airbubba]

What bus supplies the electric motor ?

The Battery Bus (not the Hot Battery Bus, i.e. the Battery switch must be on).

[grebllaw123d]

questions in #208

arc-en-ciel,

I will try to answer your questions:

ad.1: I flew the B767 for many years and experienced 2 cases of leak from the CTR HYD SYST - in both cases the leak stopped completely after performing the malfunction checklist, which requires that all 3 HYD pumps are switched off. So I do not think that your concern is relevant in case of the B767.

ad.2: At this point nobody knows, but it should not be too difficult to find out. A post on another pilot website claims that the circuit breaker for the alternate extension system had popped and could not be reset.

[Admiral346]

No, loosing a HYD SYS on an a340 would, ad definitionam, of course not be an ETOPS problems. ETOPS refers to TWINS, hence the meaning of ETOPS!

I still wouldn't take an A340 running on 2 HYD SYS only across the Atlantic or any other remote part of the world. Why do you think they give it 3?

And 767jock:

"is it wise to leave an hydraulic system leaking everywhere inside for 7/8 hours ? "
Do your homework please. If pressure cannot be restored, the QRH directs that all the associated system pumps are selected off.

Well, before you tell others to do their homework - how about a deep long meditation on HYD SYS functions - is there not a reservoir pressurized to even out the bumps? Wouldn't it be pushing the soup out, and wouldn't it be flowing out after time anyways? And why do we switch off the pumps? To keep the fluid in the lines? No, sir, you switch 'em off to keep them from running dry and getting ruined...

[jamesbond6]

Originally Posted by Starbear

In short, yes it is. To use ALTN Gear extension, the Landing Gear Lever should be in the OFF postion (hydraulics in a "runaround" type circuit) so if there is any hydraulic pressure available, gravity extension will merely push the fluid around the circuit. If the lever is left in the UP postion then its possible for fluid/pressure to be trapped in up circuit and so resist gravity extension.

But question is whether committing such an error once could possibly lead to no further possibility to extend the gear in any manner. That would be too simple explanation if systems allowed for such a simple pilot error, so I suppose that reconfiguring the gear lever and switching the ALTN to DOWN again would release the pressure and allow for gravity extension, despite not having center hydraulic system available.

The latest news (released by press/airport authorities, not the airline, so please consider some bias on accuracy) on the technical part of this topic is that the gear has been extended from the inside of the aircraft (I assume it means cockpit) by the engineers sent by Boeing. So could it have been possible after all?...

[NigelOnDraft]

I still wouldn't take an A340 running on 2 HYD SYS only across the Atlantic or any other remote part of the world. Why do you think they give it 3?

So it could continue a flight to destination in the event of loss of 1

[grebllaw123d]

jamesbond6,

You wrote:

"The latest news (released by press/airport authorities, not the airline, so please consider some bias on accuracy) on the technical part of this topic is that the gear has been extended from the inside of the aircraft (I assume it means cockpit) by the engineers sent by Boeing. So could it have been possible after all?..."

Another explanation could be that the fault in the alternate extension system had been found and rectified!

I doubt that the crew made mistakes - they had lots of time and apparently had great help from the company - see #189 below

#189:
they were in touch with ops, mechanics, and training captain, and circuit breakers were one of the first things they checked, and quite extensively. We we listening to their freq on twr.

[Airbubba]

No, loosing a HYD SYS on an a340 would, ad definitionam, of course not be an ETOPS problems. ETOPS refers to TWINS, hence the meaning of ETOPS!

Well, actually, FAA ETOPS now applies to four (and three) engine aircraft over 180 minutes from an airport. It's been in effect for almost five years now, with a one year grace period.

See: AERO - The New FAA Etops Rule

Airbuba,

I have tried to look around and find something as you had requested, but I am not sure it's a final answer to your question.

Thanks, I saw that also, and the FAA ETOPS circular mentions a systems evaluation before going feet wet. Still, I wish the guidance were more clear if I someday find myself at the end of a long green table with no ashtray.

[pley]

Another video

Guys, I just registered to post the link to another vid that was recorded from the rear. Here you can see how 'soft' landing it was! Amazing.

Awaryjne L

[arc-en-ciel]

grebllaw123d

thanks for your answers,

so if it is not the electrical supply (the bat bus) then it could be:
- the switch (not connected)
- the line (cut)
- the electrical motor (damaged)

what else ?!?