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Fuel, Wt, And Emergency Landing Question  
User currently offlineDavescj From United States of America, joined Jun 2007, 2307 posts, RR: 0
Posted (6 years 10 months 1 week 3 days 23 hours ago) and read 4811 times:

On one of the threads in Civil Aviation, one of the busted myths is that at the end of a long flight, pilots dump fuel to bring a large get down to a safe landing weight. As was pointed out, not only is this environmentally bad, but expensive with the cost of jet fuel. As a result, use of fuel is calculated in advance. Further, not all planes can dump fuel mid -- air they said.

So my question is if a plane can't dump fuel (as it isn't equipped for example) what does a plane to lower weight to max landing weight if you MUST land immediately after take off (ex: a large bird flies into an engine, as happened to a 757 for Thomas Cook Airways, took of from Manchester, about 15 seconds into take off, bird flies into engine, must now make emergency landing due to loss of an engine, returns to Manchester safely, UTUBE video I am refering to is here

http://www.youtube.com/watch?v=9KhZwsYtNDE ).

In this case, as the gas tanks had been filled to go a couple hours away, obviously they had a good amount of fuel.

Assuming the plane was over max landing weight, what can be done to lower the weight (other than drop fuel manually)? Or can you simply land overweight and deal with that in a seperate manner? But isn't their a point where it is simply to heavy to stop on a runway (ie the proverbial runaway train/18 wheeler effect of interia).

I hope the question made sense.

Thanks for the answers!

Dave


Can I have a mojito on this flight?
15 replies: All unread, jump to last
 
User currently offlinePhilSquares From , joined Dec 1969, posts, RR:
Reply 1, posted (6 years 10 months 1 week 3 days 23 hours ago) and read 4807 times:

Quoting Davescj (Thread starter):
Or can you simply land overweight and deal with that in a seperate manner? But isn't their a point where it is simply to heavy to stop on a runway (ie the proverbial runaway train/18 wheeler effect of interia).

You just simply land overweight. Here's a section of the Flight Crew Training Manual (FCTM) from the 747-400.

OVERWEIGHT LANDING
Overweight landings may be safely accomplished by using normal landing
procedures and techniques. There are no adverse handling
characteristics associated with overweight landings. Landing distance is
normally less than takeoff distance for flaps 25 or 30 landings at all gross
weights. However, wet or slippery runway field length requirements
should be verified from the landing distance charts in the Performance
Inflight chapter of the QRH. Brake energy limits will not be exceeded for
flaps 25 or 30 landings at all gross weights.
Note: If flaps 30 approach speed (VREF 30 + additives for wind and
gusts) is higher than 167 knots, use flaps 25 and VREF 25 for
landing.
If stopping distance is a concern, reduce the landing weight as much as
possible. At the captain’s discretion, consider fuel jettison or reduce
weight by holding at low altitude with a high drag configuration (gear
down) to achieve maximum fuel burn-off.
Analysis has determined that, when landing at high gross weights at
speeds associated with non-normal procedures requiring flaps set at 25,
maximum effort stops may exceed the brake energy limits. The gross
weights where this condition can occur are well above maximum landing
weights. For these non-normal landings, maximize use of the available
runway for stopping.
Observe flap placard speeds during flap extension and on final approach.
In the holding and approach patterns, maneuvers should be flown at the
normal maneuver speeds.
Note: For overweight landings, flaps up command speed should be set
no lower than VREF + 100.
Use the longest available runway, and consider wind and slope effects.
Where possible avoid landing in tailwinds, on runways with negative slope,
or on runways with less than normal braking conditions. Do not carry
excess airspeed on final. This is especially important when landing during
an engine inoperative or other non-normal condition. At weights above the
maximum landing weight, the final approach maximum wind correction
may be limited by the flap placards and load relief system.
Fly a normal profile. Ensure that a higher than normal rate of descent
does not develop. Do not hold the airplane off waiting for a smooth
landing. Fly the airplane onto the runway at the normal touchdown point.
If a long landing is likely to occur, go-around. After touchdown,
immediately apply maximum reverse thrust using all of the available
runway for stopping to minimize brake temperatures. Do not attempt to
make an early runway turnoff.
Autobrake stopping distance guidance is contained in the Performance
Inflight section of the QRH. If adequate stopping distance is available
based upon approach speed, runway conditions, and runway length, the
recommended autobrake setting should be used.


On the 400, you take off at 397.8(396 744F) Tons and come right back and land even though the MLW is 285.7 (302 744F)

[Edited 2007-12-15 02:59:33]

User currently offlineWILCO737 From Greenland, joined Jun 2004, 9076 posts, RR: 76
Reply 2, posted (6 years 10 months 1 week 3 days 23 hours ago) and read 4807 times:
AIRLINERS.NET CREW
HEAD MODERATOR

Well, you can and have to do an overweight landing if necessary! If you have a fire on board and need to land ASAP you just do it! Try to achieve a not too hard touchdown, but dont waste any runway because the approach speed will be pretty high due to the high weight...

If you cant dump fuel then you have to circle around until you reached your MLAW (max landing weight). But the question is: how long do you want to circle in a holding pattern on just one engine?

On short haul aircrafts the difference between MTOW and MLAW is not so significant. 737-300 MTOW (at LH) is 57.6tons and MLAW is 52.6. So even if you take off with MTOW and land straight away you have burnt a little fuel already and then most runways are long enough to stop the "small" aircraft on the runway.

On long haul aircrafts the difference between MTOW and MLAW is significant! MD11F is MTOW 285.990 tons and MLAW is 222.900 tons... So if you take off with 286 tons and land straight again, you are for sure overweight! But what will you do when there is fire on board?! LAND that damn thing ASAP on the longest available runway in your closest vicinity!!!

If you have enough time then you can dump fuel of course. Fly to a dumping area, dump the fuel and land without any problems!

WILCO737 (MD11F)
 airplane 



It it's not Boeing, I am not going.
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17068 posts, RR: 66
Reply 3, posted (6 years 10 months 1 week 3 days 21 hours ago) and read 4790 times:



Quoting Davescj (Thread starter):
So my question is if a plane can't dump fuel (as it isn't equipped for example) what does a plane to lower weight to max landing weight if you MUST land immediately after take off (ex: a large bird flies into an engine, as happened to a 757 for Thomas Cook Airways, took of from Manchester, about 15 seconds into take off, bird flies into engine, must now make emergency landing due to loss of an engine, returns to Manchester safely, UTUBE video I am refering to is here

I don't know if that plane really needed to land immediately. I mean, it could have burned off fuel if the pilots had felt that they preferred to lower the weight of the aircraft before landing.

Quoting Davescj (Thread starter):
Assuming the plane was over max landing weight, what can be done to lower the weight (other than drop fuel manually)?

Fly around for a while. Contrary to public belief, most aircraft in the sky don't have fuel dumping capability. It's typically limited to widebodies. This is because, as WILCO737 mentiones, narrowbodies don't have a huge difference between MTOW and MLAW.

Quoting Davescj (Thread starter):
Or can you simply land overweight and deal with that in a seperate manner?

Sure. The aircraft can land overweight. You then have to carry out a check to see that there was no damage.

Quoting Davescj (Thread starter):
But isn't their a point where it is simply to heavy to stop on a runway (ie the proverbial runaway train/18 wheeler effect of interia).

Every single landing means calculating if there is enough runway. Heavier aircraft means longer runway required. There is no critical point where the aircraft can't brake.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineTbanger From Australia, joined Jul 2004, 266 posts, RR: 0
Reply 4, posted (6 years 10 months 1 week 3 days 12 hours ago) and read 4728 times:



Quoting Starlionblue (Reply 3):
don't know if that plane really needed to land immediately. I mean, it could have burned off fuel if the pilots had felt that they preferred to lower the weight of the aircraft before landing.

You are right....and it didn't land immediately. The actual flight was around 45 minutes. They held at Wallasey VOR while they ran through the abnormal landing checklist and gave the flight attendants time to do a pax briefing.

The flight took off around 09:15 and by the news report that was out at the time said the flight landed back at MAN at around 10:00am.


User currently offlineViscount724 From Switzerland, joined Oct 2006, 25626 posts, RR: 22
Reply 5, posted (6 years 10 months 1 week 3 days 12 hours ago) and read 4721 times:

The JetBlue A320 that diverted to LAX in 2005 with a nose gear problem (wheels cocked sideways) after departure from BUR for JFK circled for about 3 hours burning off fuel before landing.
http://aviation-safety.net/database/record.php?id=20050921-0

You've probably seen one of several videos of that landing.
http://www.youtube.com/watch?v=FoMf7lTpWzU


User currently offlineStealthZ From Australia, joined Feb 2005, 5714 posts, RR: 44
Reply 6, posted (6 years 10 months 1 week 3 days 10 hours ago) and read 4699 times:
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Quoting Viscount724 (Reply 5):
The JetBlue A320 that diverted to LAX in 2005 with a nose gear problem (wheels cocked sideways) after departure from BUR for JFK circled for about 3 hours burning off fuel before landing.

You can afford to do that, that aircraft did not have an inflight emergency, it had a landing issue.

If the aircraft was on fire, or they suspected one you can bet they would not have delayed the landing



If your camera sends text messages, that could explain why your photos are rubbish!
User currently offlineSNAFlyboy From United States of America, joined Oct 2007, 86 posts, RR: 0
Reply 7, posted (6 years 10 months 1 week 3 days 8 hours ago) and read 4694 times:

In another thread, 2H4 predicted that, as fuel prices continue to climb, it will actually become more economical for airlines to just dump passenger bags out of the cargo hold in order decrease landing weight rather than dumping the fuel! This would be a particularly helpful practice on those aircraft not equipped with fuel dump systems...  Big grin

Or...you could just do the more logical thing and circle around for a couple of hours. Realistically speaking of course, if you plane is in flames, stressing it with an unusually high landing weight is probably the least of your worries..

~SNAFlyboy


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17068 posts, RR: 66
Reply 8, posted (6 years 10 months 1 week 2 days 19 hours ago) and read 4631 times:



Quoting SNAFlyboy (Reply 7):
Or...you could just do the more logical thing and circle around for a couple of hours. Realistically speaking of course, if you plane is in flames, stressing it with an unusually high landing weight is probably the least of your worries..

Indeed. The central point, I guess, is that landing weight is not the primary consideration when deciding to land now or later. If you have to land immediately, you do, and deal with any overweight issues. If you can land later, you consider weight issues and decide how much later.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineViscount724 From Switzerland, joined Oct 2006, 25626 posts, RR: 22
Reply 9, posted (6 years 10 months 1 week 2 days 16 hours ago) and read 4613 times:



Quoting SNAFlyboy (Reply 7):
In another thread, 2H4 predicted that, as fuel prices continue to climb, it will actually become more economical for airlines to just dump passenger bags out of the cargo hold in order decrease landing weight rather than dumping the fuel! This would be a particularly helpful practice on those aircraft not equipped with fuel dump systems...

But the fuel savings could well be offset by the lawsuits and resulting settlements to those whose heads the bags landed on....or roofs they plummeted through, plus the claims by passengers for the ejected bags and their contents.  Smile


User currently offlineSNAFlyboy From United States of America, joined Oct 2007, 86 posts, RR: 0
Reply 10, posted (6 years 10 months 1 week 2 days 14 hours ago) and read 4594 times:



Quoting Starlionblue (Reply 8):
If you have to land immediately, you do, and deal with any overweight issues. If you can land later, you consider weight issues and decide how much later.

Well said! I guess this is pretty much the general point.

Quoting Viscount724 (Reply 9):
But the fuel savings could well be offset by the lawsuits and resulting settlements to those whose heads the bags landed on...

Hmm, good point. I think we failed to take into account the death of bystanders from falling luggage in that last discussion... Oops.  worried 

~SNAFlyboy


User currently offlineAskr From Poland, joined Mar 2008, 45 posts, RR: 0
Reply 11, posted (6 years 6 months 1 day 11 hours ago) and read 4274 times:



Quoting Viscount724 (Reply 9):

But the fuel savings could well be offset by the lawsuits and resulting settlements to those whose heads the bags landed on....or roofs they plummeted through, plus the claims by passengers for the ejected bags and their contents.

There should be designated luggage dumping areas - far from populated areas, or over water.
The area could than be designated into two parts, with licenced operators cleaning the each area every second day / week etc.

Unlawful collectors would be subject to legal luggage bombardment with no rights to sue  Wink



ATC-PL Wanabe :) - 2nd application is in... 11 July...
User currently offlineFlighty From United States of America, joined Apr 2007, 8629 posts, RR: 2
Reply 12, posted (6 years 6 months 17 hours ago) and read 4204 times:



Quoting SNAFlyboy (Reply 7):
n another thread, 2H4 predicted that, as fuel prices continue to climb, it will actually become more economical for airlines to just dump passenger bags out of the cargo hold

Or excess F/As  goodvibes 


User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 13, posted (6 years 6 months 2 hours ago) and read 4129 times:



Quoting Davescj (Thread starter):
So my question is if a plane can't dump fuel (as it isn't equipped for example) what does a plane to lower weight to max landing weight if you MUST land immediately after take off

Land, deal with the other consequences later.

Keep in mind that there is no inherent reason there will be negative consequences from an overweight landing. That fact that the aircraft took off proves that the gear and airframe can support the aircraft on the ground at the necessary speed. If we assume that the takeoff was per regulations, we know that the aircraft has enough braking power to get up to V1 and then come to a complete stop at MTOW. In the case of the notional landing, you're basically at MTOW but can use the whole runway, not just the part that's left after you accelerate to V1.

Provided you don't smack down on the landing gear and force the oleo's to absorb way more energy than they want to (or bottom out and drive that energy into the structure) the overweight landing shouldn't do any harm to the aircraft, other than probably new tires and brakes because I'd be hitting max autobrake in a situation like that.

Tom


User currently offlineTristarSteve From Sweden, joined Nov 2005, 4022 posts, RR: 33
Reply 14, posted (6 years 5 months 4 weeks 1 day 18 hours ago) and read 4095 times:



Quoting PhilSquares (Reply 1):
Analysis has determined that, when landing at high gross weights at
speeds associated with non-normal procedures requiring flaps set at 25,
maximum effort stops may exceed the brake energy limits.



Quoting Tdscanuck (Reply 13):
the overweight landing shouldn't do any harm to the aircraft, other than probably new tires and brakes because I'd be hitting max autobrake in a situation like that.

Only seen it once. A B747-200 took off from BAH to SIN, Engine fire warning on rotation. Both bottles fired and the warning remained. So one circle and landed. Parked on our ramp and we went out to it. It was a false warning. The electricain quickly found the fault, I had arrived with two fire bottles to change and all was going well. It looked like we could fix it before the crew went out of hours. Then the fusible plugs started fusing. When the third wheel deflated the service got nightstopped, as we only had two wheels!


User currently onlineMD11Engineer From Azerbaijan, joined Oct 2003, 14060 posts, RR: 62
Reply 15, posted (6 years 5 months 4 weeks 1 day 13 hours ago) and read 4078 times:

From a maintenance point of view, we'll have to do an overweight landing inspection. If the pilot greased the plane on the runway and did not allow exessive sink rates to develop, we'll essentially have a look at the wheels and brakes and the plane might be a while on the ground to let the brakes cool down (had it last week, when one of our 737NGs had a medical emergency just after take-off, fueled for a trip from Germany to Morocco, I advised the pilots to wait for an hour with parking brakes released, while the ambulance crew was treating the ill passenger and while his and his family's luggage was recovered from the cargo hold).

If the pilot on the other hand slammed the plane onto the runway, a hard landing inspection will be added. On the 737NG, it consists of two parts. The first stage is a good walkaround with emphasis on the landing gear and gear attachment points, keel beam, engine pylons, fuselage and wing skin for wrinkles, cracks, distortion or damaged rivets, a visual inspection of the aft pressure bulkhead and the area, where the zone aft of the aft pressure bulkhead attaches to the bulkhead. The interior is also checked for e.g. PSUs, which might have come down or loose ceiling panels. If anything is found, the second stage will be initialized, which is in depth inspection of the plane, requiring the opening of access panels and revoval of fairings to get access to the structure.

Jan


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