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Why does a plane have to 'dump' fuel before landing?

Discussion in 'AviatorChat.com' started by 96redLT4, Jan 17, 2020.

  1. Bob Parks

    Bob Parks F1 Veteran
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    I worked with a lot of experts on the 777 (and others before) and I will always remember one engineering supervisor that was posed an important design change to lighten some structure (always an issue). After a lengthy analysis of maybe 2 seconds he said, " That S.O.B. will break."
     
  2. tantumaude

    tantumaude Formula Junior
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    We've had a few have to dump fuel over Lake Ontario before coming in. Usually they are able it it's a maintenance issue.
    Something like a heart attack, I've had a B777 take off, turn around an hour out and do 250kts to 4 miles final, drop the anchor and land at close to 180. ARFF did a 2 minute inspection of the hot brakes, then the pilot raced to the gate at 45-50 kts taxi speed. It was epic to see. I heard the aircraft was out for three days getting all the gear serviced and airframe inspected.
     
  3. Gatorrari

    Gatorrari F1 World Champ
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    Considering that the airport was LAX, you think they'd be able to fly out to the ocean and do their fuel-dump there.
     
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  4. tazandjan

    tazandjan Three Time F1 World Champ
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    Single engine, heavyweight, he may have just wanted to get her on the ground expeditiously. Nobody got killed, so at least one good outcome.

    I am sure the Monday morning quarterbacks will pick what he did to death, just like they did with Sully, and nobody got killed that time, either.
     
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  5. ylshih

    ylshih Global Moderator
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  6. BJK

    BJK Formula 3

    Jul 18, 2014
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    ABC News:
    During the landing, the pilot was specifically asked (TWICE) by the Air Traffic Control System Command Center if there was a need to dump fuel in order to lighten the weight.
    "The pilot replied by saying 'negative (TWICE)...we've got it under control.' Had the pilot notified (air traffic control), the flight would have been directed to a location and altitude that fuel could be safely dumped," said Allred, who is suing the airline for negligence.
     
  7. ChadR

    ChadR Karting

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    I bet by next year or so, you'll hear they are developing electric aircraft.:D
     
  8. Bob Parks

    Bob Parks F1 Veteran
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    I got to thinking about some of the engineers with whom I worked and the most impressive was the engineer in charge of the 727 wings. I was gathering information on the wing structure for my training class and I went to the building where the wing group was. There in the middle of a fairly large bay they had set up six or eight lofting tables all joined together, making a very big flat "board "on which to work. On them was a half sized drawing of the lower wing skin and ribs. There must have been eight engineers and draftsmen on their hands and knees making changes to the drawing. In the middle of them was the head guy, chief engineer Omar B., drawing new patterns and profiles of the pad ups that were to be machined into the skin. Previous airplanes had doublers and triplers riveted in place. The 727 was to have machined planks where the thinner areas were machined away from the thicker areas. Omar had his shirt sleeves rolled up, tie off, shoes off, and wielding a big red pencil to redraw his modifications to the design. " I want this pad to extend to the next rib and the sides of it to blend more to the spars." I don't remember his exact words but you get the essence. After an animated discussion with the crew he said, " I don't care what weights and stress said, this is the way it is going to be." He sat cross-legged on the drawing while he explained the changes and chatted with his people in a relaxed almost luncheon style atmosphere. Nobody challenged him. I approached him to get my info and asked him if he had worked out the changes with Loads and and he said," Well yeah, sort of, but I had it all figured out." I asked him how he could do that and he said, " Bob, this stuff is a black art and if you are working it for years , you know what to do." In the following years I worked with him many times and he was always a friendly and accommodating man who freely dispensed his knowledge with anybody. A great guy!. The 727 is a great airplane, too.
     
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  9. jcurry

    jcurry F1 World Champ
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    Sort of goes along with 'if it doesn't look right, it probably isn't'. Some things only experience can teach, and by experience I mean more than just time on a job.
     
  10. tazandjan

    tazandjan Three Time F1 World Champ
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    TLAR and experience, combined with engineering rules of thumb, can go a long ways towards getting things right. Computer programs sometimes cut things a bit too finely.

    On the 777, the whole thing may have come down to the realization of "Uh Oh, I am sinking".
     
  11. Texas Forever

    Texas Forever Four Time F1 World Champ
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    Quick story: I once was flying a quick jump from DFW to IAH. At the last minute, there was a change in equipment. After boarding we sat for a while and the captain came on and said, “Folks, this new plane has too much fuel to fly straight to Houston. So we’re going to have to fly out to El Paso and circle back before we can land in Houston, which will make our arrival even later. But the good news is there is a direct flight to Houston leaving in 20 minutes if you want to deplane and take that flight.”

    Everyone immediately jumped up got their bags and started pushing and shoving to change planes. Me, I was dead dog tired after being on my feet all day (it was around 8:30). I said **** it, I had a window seat, and closed my eyes. After everybody left, I heard the cabin door close. The captain then came on and said, “Good news. Enough people left we can now fly direct to Houston. Enjoy the flight.”

    We got there before the other flight.


    Sent from my iPhone using FerrariChat.com mobile app
     
  12. Rifledriver

    Rifledriver Two Time F1 World Champ

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    I had the only empty seat on the entire airplane next to me on a 747 once. Just before push back the stew came and mentioned it and asked if I would switch seats with some newlyweds who could not get seats together. It was a long flight but I sighed and said sure. Stew smiled at me and said congrats, you're flying first class!. I marched to the front of the airplane and hooked up the champagne IV and had a very nice flight.
     
  13. Gatorrari

    Gatorrari F1 World Champ
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    One of the funniest airline stories that I've read in years! :D:D:D
     
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  14. killer58

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    More than likely irrelevant. During an emergency, ATC is there to assist, not control.


    This !!

    I can see the crew making the decision only after getting dirty on final and realizing they were too heavy.
     
  15. jcurry

    jcurry F1 World Champ
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    Did the pilots declare an emergency?
     
  16. Ferrari 308 GTB

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    From what i heard ,no.

    Total flight from t/o to landing was around 25 minutes.

    If they started dumping fuel on the T7 ,it would normally automatically stop at MLW or when manually turned off... maybe they somehow just forgot to turn it off until late on the approach?

    Hard to imagine,especially with another set of crew just behind them.
     
  17. killer58

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    ATC doesn't always ask if you are specifically declaring and emergency. It depends on the situation.
    Once the crew reported an engine problem (reportedly compressor stalls) and requested an immediate return for landing, that might have sufficed for an official declaration.

    By all accounts, the crew certainly thought is was an emergency, and that's all that matters.
     
  18. jcurry

    jcurry F1 World Champ
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    That is not correct. The crew must specifically declare an emergency, not the controllers. The controllers may think the situation might rise to that occasion and even ask the pilots if they are declaring an emergency. However until the pilots declare such the controllers will not treat it will all the resulting protocols and thus they are not just in an advisory mode.
     
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  19. Gatorrari

    Gatorrari F1 World Champ
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    That was the situation with the Avianca 707 that crashed on Long Island after running out of fuel. The pilot never used the word "emergency" during his communications with the controllers; if he had, ATC probably would have given him a quicker path to JFK and the plane would have landed safely.
     
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  20. Ferrari 308 GTB

    Ferrari 308 GTB F1 Veteran

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    Delta 95 ,a few years ago. Declared Emergency ,when asked by ATC.

     
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  21. Ferrari 308 GTB

    Ferrari 308 GTB F1 Veteran

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  22. killer58

    killer58 Formula 3
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    In general, you are correct. As I stated, “it depends.”

    I’ve had five emergency landings.
    Only once did ATC ask me specifically if I was declaring it.
    The other four, they didn’t need to.
     
  23. David_S

    David_S F1 Veteran
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    Maybe just fly "dirty" with the gear down, as far as you can between that location and the desired destination, until you either reach the destination, or an intermediate airport that can accommodate the aircraft landing? Sure seems more efficient to use up the fuel heading to the final destination, than to dump it - at least for something like stuck landing gear.
     
  24. tazandjan

    tazandjan Three Time F1 World Champ
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    David- There are strict airspeed limits on flying with the gear down and the fuel consumption goes way up with a dirty aircraft. Not to mention which, the lower airspeed limits how high you can go, and that further drastically increases fuel consumption. Not feasible at all practically.
     
  25. Whisky

    Whisky F1 World Champ
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    I flew LAX quite a bit in the 80's, one time there were 17 passengers total, on a 727.
    The stewardess just told all of us: 'y'all just come on up to first class...'
     

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