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169west
12th Mar 2010, 05:48
What are the reasons/conditions you are performing Heavy Weight Emergency Return and the procedures/technics in you adopt in your airline/plane?

Wizofoz
12th Mar 2010, 09:59
It is very much a judgment thing on the day, and depends on a lot of factors.

Some situations are no-brainers such as an uncontained fire or extremely critical medical case, but in a lot of others it's going to be a decision by the commander depending on the nature of the emergency and the conditions at the field (WX, runway length etc.)

For example, if I had to shut down an engine due to an oil leak, and the other was running fine, I'd be happy to take the time to jettison, whilst keeping an Eagle eye on the good engine, and putting myself in a position where a quick approach could be made if the other one developed problems.

If I just had an unexplained flame-out, I'd be wondering about contaminated fuel, and probably opt for an overweight landing, field conditions allowing.

On the 777 the OW landing C/list simply instructs you to check the landing climb limit, and gives you the option of a flap 20 landing.

It should also be noted, however, that in an overweight landing, it's not hard to melt thermal plugs, and braking should be used with that in mind.

PappyJ
12th Mar 2010, 16:54
Wizo has pretty much summed it all up. :ok:

bumba
13th Mar 2010, 07:12
I know it can sound strange, but on the 777 do you calculate the landing distance with the t/o weight? In other words, at the t/o do you know your landing roll with weight your are taking off?

169west
13th Mar 2010, 07:58
Ok... reducing possible variables!

let say that the scenario is more or less the same as the Thomsonfly 757 bird strike in Manchester, but with the difference that you are not able to switch off the engine .....

............ you have control!

Wizofoz
13th Mar 2010, 17:34
Bumba,

Not before takeoff, no, but think of it this way- we have a V1 which is achieved near the end of the take-off roll and from which we know we can stop the aircraft in the runway remaining.

It is therefore pretty much certain that if land in the firt 450m of the same runway at the same weight, we are going to be able to stop!!

mustafagander
14th Mar 2010, 05:12
Careful Wizzo!!

It is well known that the B767 for one can often be way above the brake energy limit in an overweight landing. Recall that Vref will likely be well above V1 and energy is V*2. Think about the engine uncontrollable fire scenario with F20 landing required.

In general what you say is, of course, correct but there are certain a/c types and certain runway lengths which will cause a very surprised look on the faces of those who haven't done their homework!! :eek:

Naturally if you, Captain, decide on the day that you MUST land NOW then just do it and maybe bust up the airframe as you depart the end of the runway. With any luck all hands will be able to run away to fly another day and you will have satisfied your primary responsibility to the pax, kept 'em alive.

lion-g
14th Mar 2010, 05:49
Hi,

For some aircraft type like the A380, especially for long sectors, we can't jettison to max landing weight. This is due to the fact that the fuel in the feed tanks cannot be jettison.

For what I know, 380 is certified to land at Max Takeoff weight !! Thus, even for non-time critical fault we have to land overweight.

But of course, if there's a flight controls / landing gear problem, we might try to hold and burn the fuel just to go below our max landing weight.

Just my 2 cents worth,

Cheers

Wizofoz
14th Mar 2010, 06:52
l-g,

737s,767s and 777s are also certified to land at MTOW, with just an inspection required (Don't know about 747, can anyone enlighten?)

I believe that the A380 has a three stage deal where, as you say, it can land at MTOW, but requires an inspection. It has another weight, greater than MLW but less than MTOW at which it can land and not require an inspection because of the un-jettisonable fuel as you mention.

Musta, quite true!!

NO LAND 3
14th Mar 2010, 08:57
How about this (as far as B777 goes):

The only relevance MLW has after an engine failure is that the Overweight Landing checklist will prohibit you from doing a F30 landing.

My opinion is that following an engine failure on a two engine aircraft one should land as soon as practical so long as landing performance is adequate. The last part of that statement is, of course, very subjective and it is desirable to use any time in hand to reduce weight.

Essentially what I am saying is that it is not necessary to spend an hour jettisoning 100 tonnes of fuel when a 4000m runway is available. Some intermediate ammount can be settled on, for example one which won't melt the brake fuses.

169west
16th Mar 2010, 13:34
I have heard that HAL has a Diamond Check-list to use in case of an emergency return. So you do not have to run the after t/o, descent, approach check list!

... and here is the link for the ThomsonFly (http://www.youtube.com/watch?v=9KhZwsYtNDE) 757 bird strike