Was It? Would dumping fuel have saved any lives? No, everyone lived anyway.
Quoting Bongo (Reply 5): I mean just to avoid three hours of suffering
I fail to see how any more mental stress was caused by 3hrs of circling than coming in minutes after the problem was realized.. I think they turned off the IFE, if I was wasting 3hrs not going anywhere watching some TV would have been nice.
FrancoBlanco From , joined Dec 1969, posts, RR: Reply 7, posted (7 years 8 months 2 days 7 hours ago) and read 4824 times:
Smaller A/C don´t need a jettison system because, as you can see in this case, you can simply fly in circles for a few hours or even less and burn the fuel. If you don´t have that time, e.g. because of a burning engine, simply land the plane. You can´t be that much overweight with an A320.
Fuel Jettison only exists in larger planes because e.g. a fully loaded 747 with 150 tons of fuel on board would be terribly overweight and it would be dangerous to land in that case. On the other hand, burning 150 tons of fuel by flying in circles would definitely take too much time and that´s why larger A/C can dump fuel.
Jetlagged From United Kingdom, joined Jan 2005, 2452 posts, RR: 17 Reply 8, posted (7 years 8 months 2 days 7 hours ago) and read 4792 times:
Quoting FrancoBlanco (Reply 7): Fuel Jettison only exists in larger planes because e.g. a fully loaded 747 with 150 tons of fuel on board would be terribly overweight and it would be dangerous to land in that case. On the other hand, burning 150 tons of fuel by flying in circles would definitely take too much time and that´s why larger A/C can dump fuel.
Fuel dumping takes a long time too, though it's faster than just burning it. A 747 on fire would land ASAP, regardless of weight.
It's nothing to do with how long it will take to burn off fuel. The requirement for a fuel dumping system is set out in the appropriate FAR. It's to do with the ability of the aircraft to climb in approach and landing configurations at max takeoff weight less 15 minutes fuel burn (making a go-around possible). Heavy three and four engined aircraft struggle in these configurations, so need to land at much lighter weights hence require fuel dumping capability.
The only reason for the 3 hour hold was to land at the minimum weight possible because wheel braking will be kept to a minimum and reverse thrust not used at all to reduce the load on the nose gear.
It would have been just the same had the aircraft been a 737.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
Rick767 From United Kingdom, joined Jan 2000, 2662 posts, RR: 52 Reply 9, posted (7 years 8 months 2 days 5 hours ago) and read 4723 times:
Quoting FrancoBlanco (Reply 7): Fuel Jettison only exists in larger planes because e.g. a fully loaded 747 with 150 tons of fuel on board would be terribly overweight and it would be dangerous to land in that case
This is a common misconception, it is not dangerous to land overweight (provided runway length is checked and acceptable, etc..) and modern aircraft are certified to land up to Maximum Takeoff Weight in an emergency.
There may be some slight damage / overstress, but it is not unsafe.
I used to love the smell of Jet-A in the morning...
FrancoBlanco From , joined Dec 1969, posts, RR: Reply 10, posted (7 years 8 months 2 days 5 hours ago) and read 4703 times:
Well, yeah, I simplified it a bit.
It´s not dangerous or unsafe to land overweight, if you have to do it then do it, of course, I just wanted to point out that a 747 landing at 397 tons is a bit different than an A320 at 54 tons.
B744F From Germany, joined Jan 2006, 0 posts, RR: 0 Reply 11, posted (7 years 8 months 2 days 4 hours ago) and read 4653 times:
It is not needed? As a safety precaution, why wouldn't you want this option? If you needed to dump as much fuel as possible to have a better chance of surviving the landing... who on earth would say NO and why?
Frequentflyer From United States of America, joined Jul 2005, 736 posts, RR: 3 Reply 12, posted (7 years 8 months 2 days 4 hours ago) and read 4647 times:
Quoting Rick767 (Reply 9): modern aircraft are certified to land up to Maximum Takeoff Weight in an emergency.
LeanOfPeak From United States of America, joined Oct 2004, 509 posts, RR: 1 Reply 14, posted (7 years 8 months 2 days 3 hours ago) and read 4613 times:
Quoting B744F (Reply 11): It is not needed? As a safety precaution, why wouldn't you want this option? If you needed to dump as much fuel as possible to have a better chance of surviving the landing... who on earth would say NO and why?
Incorporating fuel dump capability adds weight, maintenance, and complexity. Carrying weight around adds to fuel requirements. Carrying that added fuel around adds to fuel requirements. And on and on. If a truly immediate landing is necessary, it would probably be a heavier landing with fuel dump than without it.
In this particular case, minimizing the landing weight significantly improved the chances of a successful outcome. And in this particular case, there was no time constraint to make burning off fuel unpalatable.
There is very little overlap between situations in which it is vital to get on the ground immediately and situations in which getting the weight to the bare minimum significantly improves the safety of the landing.
An A320 at MTOW is 14% over MLW. An MD-11 at MTOW is 25% over MLW. A 744 at MTOW is 50% over MLW. It's an entirely different class of problem and, for most emergencies, a 14% overweight landing should not materially impact the immediate well-being of the people aboard. The most obvious exception, of course, being landing gear misconfiguration, in which case there is generally minimal time constraint on getting the weight down.
Thanks, Frequentflyer and Pope, for alluding to SwissAir 111, as it is relevant here. That MD-11 was equipped with fuel dump and the decision was made, after a report of smoke in the cabin, to circle over the ocean to dump more fuel before landing (Remember, fuel dump isn't like a firebomber, so it does still take time to lower the level in the tanks). The ensuing crash has led not only to changes in insulation and smoke detection, but also to a greater emphasis in procedures and training on landing immediately, even if overweight, in the event of smoke in the cabin.
Pihero From France, joined Jan 2005, 3496 posts, RR: 72 Reply 15, posted (7 years 8 months 2 days ago) and read 4553 times:
People,
The requirement for a fuel jettisonning system is to be found in the FARs.
The pertinent articles are FAR 25.1001 and the required performance in 25.119 and 25.121.
25.1001 states :
Sec. 25.1001 Fuel jettisoning system.
(a) A fuel jettisoning system must be installed on each airplane unless it is shown that the airplane meets the climb requirements of Secs. 25.119 and 25.121(d) at maximum takeoff weight, less the actual or computed weight of fuel necessary for a 15-minute flight comprised of a takeoff, go-around, and landing at the airport of departure with the airplane configuration, speed, power, and thrust the same as that used in meeting the applicable takeoff, approach, and landing climb performance requirements of this part.
(b) If a fuel jettisoning system is required it must be capable of jettisoning enough fuel within 15 minutes, starting with the weight given in paragraph (a) of this section, to enable the airplane to meet the climb requirements of Secs. 25.119 and 25.121(d), assuming that the fuel is jettisoned under the conditions, except weight, found least favorable during the flight tests prescribed in paragraph (c) of this section.
(c) Fuel jettisoning must be demonstrated beginning at maximum takeoff weight with flaps and landing gear up "
And the two sets of performance required are :
FAR 25.119, "landing climb" (all engines operating) "In the landing configuration, the steady gradient of climb may not be less than 3.2 percent, with--
(a) The engines at the power or thrust that is available eight seconds after initiation of movement of the power or thrust controls from the minimum flight idle to the go-around power or thrust setting; and
(b) A climb speed of not more than 1.3 VS."
and FAR 25.121,"Approach climb" (one engine out) " In the approach configuration corresponding to the normal all-engines-operating procedure in which VS for this configuration does not exceed 110 percent of the VS for the related landing configuration, the steady gradient of climb may not be less than 2.1 percent for two-engine airplanes, 2.4 percent for three-engine airplanes, and 2.7 percent for four engine airplanes, with--
(1) The critical engine inoperative, the remaining engines at the go-around power or thrust setting;
(2) The maximum landing weight; and
(3) A climb speed established in connection with normal landing procedures, but not exceeding 1.5 VS."
These regs are quite useful to dispel at least one misconception :
For a long range airplane, the need is to dump just enough fuel to respect the performance aspect of the requirement, not to bring the weight to at most the max landing weight.
In the Jet Blue 320 case, the situation precluded a normal braking possibility,thus requiring the lightest weight possible and the longest runway available, not even mentioning the fire department preparedness.
Jetlagged From United Kingdom, joined Jan 2005, 2452 posts, RR: 17 Reply 16, posted (7 years 8 months 1 day 22 hours ago) and read 4499 times:
Quoting Pope (Reply 13): Quoting Jetlagged (Reply 8):
A 747 on fire would land ASAP, regardless of weight.
Ask the people on the Swissair MD11 if that's how it worked.
What are you suggesting? I note you didn't quote the first sentence of my paragraph, where I pointed out that fuel dumping is itself quite a lengthy process. The Swissair crew opted to dump fuel and were not fully aware of the urgency of the situation initially. However even if they had opted for an immediate emergency landing it is doubtful whether they would have made it in time.
The people on the Swissair flight didn't really stand much of a chance either way.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
LeanOfPeak From United States of America, joined Oct 2004, 509 posts, RR: 1 Reply 17, posted (7 years 8 months 1 day 22 hours ago) and read 4495 times:
Pihero, the question I was addressing was not, "Is it legal not to have a fuel dumping system?" but rather, "Why would any company in its right mind design an aircraft without a fuel dumping system?"
Mir From United States of America, joined Jan 2004, 19700 posts, RR: 56 Reply 18, posted (7 years 8 months 1 day 21 hours ago) and read 4459 times:
Quoting LeanOfPeak (Reply 17): Pihero, the question I was addressing was not, "Is it legal not to have a fuel dumping system?" but rather, "Why would any company in its right mind design an aircraft without a fuel dumping system?"
Why put one in if you don't have to? As previously stated, a fuel dump system adds complexity (and thus cost), adds weight, and has to be maintained. If that kind of thing is not required, why make an airplane that is heavier, more expensive, and more difficult to maintain than it needs to be?
The FARs are very rigorous, and if a fuel dump system would save lives in the event of a problem, you can put money down that a dump system would be required.
-Mir
7 billion, one nation, imagination...it's a beautiful day
HAWK21M From India, joined Jan 2001, 31201 posts, RR: 58 Reply 19, posted (7 years 8 months 1 day 20 hours ago) and read 4440 times:
Quoting Jetlagged (Reply 8): The only reason for the 3 hour hold was to land at the minimum weight possible because wheel braking will be kept to a minimum and reverse thrust not used at all to reduce the load on the nose
Exactly.In case of another Emergency type maybe an overweight Landing would be attempted.
regds
MEL
Scbriml From United Kingdom, joined Jul 2003, 11359 posts, RR: 50 Reply 20, posted (7 years 8 months 1 day 18 hours ago) and read 4419 times:
Quoting LeanOfPeak (Reply 17): "Why would any company in its right mind design an aircraft without a fuel dumping system?"
Would you consider Airbus and Boeing to not be "in their right mind" then? How about Cessna, Piper, etc?
As has clearly been pointed out above, in the event of an emergency requiring a return to the departing airport shortly after take off at MTOW, it's not a problem for an A320 or 737 to land heavy. I would expect this to happen, for example, in the event of an engine failure on take off.
If the situation is not life threatening, in the JetBlue case, then the sensible thing to do is burn off as much fuel as you reasonably can before you land. It's not like they flew in circles for three hours with the plane falling to bits.
It's my guess you won't see a fuel dump system on a single-aisle plane unless mandated by the certifying authorities.
Can you find any instance of a fatal accident involving A320s or 737s where a fuel-dump system would have saved a single life?
Pihero From France, joined Jan 2005, 3496 posts, RR: 72 Reply 21, posted (7 years 8 months 1 day 16 hours ago) and read 4380 times:
LeanOfPeak,
I was just referring to the necessity of a fuel dumping system, as viewed by the certifying authorities.
On another angle, I look at the system as a safety device and not as an emergency tool, and I know I'm not alone in this way of thought : getting your weight down when you have to turn back to base, with a flight control abnormality for which a lower weight means a lower landing speed and a shorter landing distance...
In an emergency, meaning you've got to get asap on the ground is altogether another matter where time is the essence.And fuel dumping a luxury you you cannot afford...
On the Swissair subject, I did a few years ago a research on the survivability of an on-board uncontrolled fire. My broad conclusions were that if a landing was made within 15 minutes of the fire detection, one has 100% chance of escape. Thererafter, the chances drop by 5% per every extra minute spent airborne, to be virtually nil after 30 minutes. (These are ballpark figures, to allow me quicker decision making ).
Zeke From Hong Kong, joined Dec 2006, 7725 posts, RR: 73 Reply 22, posted (7 years 8 months 1 day 14 hours ago) and read 4357 times:
The A320 could have landed at any time, even straight after takeoff.
The reason for not using reverse it two fold...
1) The LDG WITH ABNORMAL L/G checklist specifically says "REVERSE .. DO NOT USE"
2) The LDG WITH ABNORMAL L/G checklist then calls for both engines to be shut down (ENG MASTERS ...OFF) once the main wheels are on the ground, but prior to the nose wheel touching.
The LDG WITH ABNORMAL L/G checklist is written assuming that the nose gear will collapse on landing. If this happens the engine will touch the ground, you want fuel to be shut off to the engine in this scenario.
As you don't know if the strut will collapse or not, the engine masters are cut prior to flying the nose onto the ground.
The checklist is well thought out, and covers situations of nose, one main, both mains, or all gear with problems.
Abnormal landing gear incidents are not a specific to A320s, or Airbus, or Boeing. They would be one of the more common "emergencies" pilots will be faced with.
Its of my view that the crew decided to burn off the excess fuel so their approach speed would be lower, to reduce the ground roll on the runway.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
HAWK21M From India, joined Jan 2001, 31201 posts, RR: 58 Reply 23, posted (7 years 8 months 1 day 11 hours ago) and read 4313 times:
Quoting Scbriml (Reply 20): As has clearly been pointed out above, in the event of an emergency requiring a return to the departing airport shortly after take off at MTOW, it's not a problem for an A320 or 737 to land heavy. I would expect this to happen, for example, in the event of an engine failure on take
Correct term would be "Overweight Landing" & not "Heavy Landing".
LeanOfPeak From United States of America, joined Oct 2004, 509 posts, RR: 1 Reply 24, posted (7 years 8 months 1 day 10 hours ago) and read 4280 times:
Quoting Scbriml (Reply 20): Would you consider Airbus and Boeing to not be "in their right mind" then? How about Cessna, Piper, etc?
As has clearly been pointed out above, in the event of an emergency requiring a return to the departing airport shortly after take off at MTOW, it's not a problem for an A320 or 737 to land heavy. I would expect this to happen, for example, in the event of an engine failure on take off.
If the situation is not life threatening, in the JetBlue case, then the sensible thing to do is burn off as much fuel as you reasonably can before you land. It's not like they flew in circles for three hours with the plane falling to bits.
It's my guess you won't see a fuel dump system on a single-aisle plane unless mandated by the certifying authorities.
Can you find any instance of a fatal accident involving A320s or 737s where a fuel-dump system would have saved a single life?
I was one of those saying all that. What I said was that was the question I was addressing.
25 Starlionblue: I think it was so JetBlue could get lots of free airtime Seriously though, great post. And where the heck is SlamClick? He used to fly the things.
26 AvionicMech: I think that the flightcrew were also more than likely talking to Maintenance Control on the radio as well to talk to them and see if they might be ab
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What I said was that was the question I was addressing.
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