KBFIspotter From United States of America, joined May 2005, 729 posts, RR: 1 Reply 2, posted (6 years 4 months 4 days 23 hours ago) and read 2375 times:
Quoting Avt007 (Reply 1): If it is fuel, it may just be from a vent.
It is streaming from the area of the fuel vent, so this is a possibility.
MD11Engineer From Germany, joined Oct 2003, 13368 posts, RR: 64 Reply 3, posted (6 years 4 months 4 days 23 hours ago) and read 2359 times:
The flaps are extended, and the fog comes right from the O/B edge of the flap. I'd rather say that it is just condensation caused by the vortex at the edge of the O/B flap.
KBFIspotter From United States of America, joined May 2005, 729 posts, RR: 1 Reply 4, posted (6 years 4 months 4 days 22 hours ago) and read 2346 times:
Quoting MD11Engineer (Reply 3): I'd rather say that it is just condensation caused by the vortex at the edge of the O/B flap.
But if you look at the location where the fog starts, it is outboard of the O/B edge of the O/B flap, and it starts in the location of the fuel vent, which tells me it is coming from there.
KBFIspotter From United States of America, joined May 2005, 729 posts, RR: 1 Reply 7, posted (6 years 4 months 4 days 20 hours ago) and read 2307 times:
Quoting LTU932 (Reply 5): If this was a fuel dump, wouldn't there have to be a nozzle somewhere on the trailing edge of the wing from where the fuel would be dumped?
This is not a fuel dump. What most likely happened is that fuel epxanded in the tanks due to increased temperatures and simply overlowed throught the fuel tank vent on the outboard wing. It happens often, and I have witnessed it several times. It even happens all the time on light aircraft.
HAWK21M From India, joined Jan 2001, 31228 posts, RR: 58 Reply 8, posted (6 years 4 months 4 days 20 hours ago) and read 2294 times:
Looks like Vapours emmitting from the Fuel Vent.Looks like the Aircraft was fuelled to capacity & the Expansion due Temp rise has caused the Spillege.Can occur on Ground too.
regds
MEL
CitationJet From United States of America, joined Mar 2003, 2249 posts, RR: 3 Reply 11, posted (6 years 4 months 4 days 10 hours ago) and read 2092 times:
TristarSteve From Sweden, joined Nov 2005, 3712 posts, RR: 34 Reply 13, posted (6 years 4 months 4 days 8 hours ago) and read 2043 times:
Quoting PPVRA (Reply 9): Interesting, thanks guys! Didn't know of the existence of fuel vents till now.
Fuel vent is not really the right word for them. They are fuel tank air vents.
On the ground when fuel is being pumped into the tanks, the displaced air comes out of here.
In flight the fwd facing NACA duct provides a slight (about 2psi) positive pressure on the fuel in the tanks.
During refuelling, if something goes wrong, fuel can end up in the vent surge tank at the wingtip. This usually hols only air, but it has been known for crews to put a couple of hundred kilos of fuel in there for a very long range flight. (illegally!) It is this fuel which you can see venting on take off in the picture. I have seen it happen with a US registered B757 leaving Europe.
The B747 is partcularly prone to this on the ramp because as the wing bends down with a full load of fuel, the vent intake ends up at the lowest point in the tank! The wing rises during the take off roll so in flight it is higher up. (Never try and store fuel in here on a B747)
AirframeAS From United States of America, joined Feb 2004, 14150 posts, RR: 26 Reply 14, posted (6 years 4 months 4 days 8 hours ago) and read 2035 times:
Quoting KBFIspotter (Reply 2): It is streaming from the area of the fuel vent, so this is a possibility.
The fuel tank air vent is much, much more closer to the wingtips than that location in the pic. Its probably about 10-12" or so from the wingtips.
747400sp From United States of America, joined Aug 2003, 3301 posts, RR: 2 Reply 16, posted (6 years 4 months 3 days 23 hours ago) and read 1901 times:
Dw747400 From United States of America, joined Aug 2001, 1245 posts, RR: 1 Reply 17, posted (6 years 4 months 3 days 23 hours ago) and read 1891 times:
Quoting 747400sp (Reply 16): Wow ! How dangerous, any jetliner should be able to jettison fuel for safety reason.
It is perfectly safe... depending on the nature of the emergency the aircraft can either hold for a few hours, or make an overweight landing. Remember, the narrow-bodies have significantly less fuel aboard than a heavy on an international flight.
KBFIspotter From United States of America, joined May 2005, 729 posts, RR: 1 Reply 18, posted (6 years 4 months 3 days 23 hours ago) and read 1885 times:
Quoting AirframeAS (Reply 14): The fuel tank air vent is much, much more closer to the wingtips than that location in the pic. Its probably about 10-12"
Actually on the 733 thru 735, it is about four to five feet from the wing tip. The area outboard the fuel vent is three interconected open bays. On WN mx task cards, these three bays are refered to as TAI exhaust bays.
Here is a photo of the vent in question... The fuel tank vent is on the left, and on the right is the surge tank pressure relief valve. The fuel vent is outboard in this photo of the right wing of a 735. The wing tip is another four to five feet outboard from the vent.
Here is a similar photo of the one in question... the mist is coming from the same location as in the one above.
L-188 From United States of America, joined Jul 1999, 29367 posts, RR: 61 Reply 19, posted (6 years 4 months 3 days 23 hours ago) and read 1884 times:
I agree with the others who say it is vapor comming out of a vent.
Back to the original question, AFAIK (without looking up the specific reg) is that any aircraft that has a MTOW heavier their the MLW is required to have the capability to dump fuel so that in an emergency it can make a landing at a weight below the MTOW.
The spread between MTOW and MLW generally is wider on longer legged aircraft, sometimes adding up thousands (tens of?) pounds of difference.
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OPNLguy From , joined Dec 1969, posts, RR: Reply 20, posted (6 years 4 months 3 days 22 hours ago) and read 1878 times:
Quoting L-188 (Reply 19): Back to the original question, AFAIK (without looking up the specific reg) is that any aircraft that has a MTOW heavier their the MLW is required to have the capability to dump fuel so that in an emergency it can make a landing at a weight below the MTOW.
As jets began flying with U.S. airlines in the late 1950s and early 1960s, the FAA rule in effect at the time mandated that if the difference between an aircraft's maximum structural takeoff weight and its maximum structural landing weight was greater than 105%, the aircraft had to have a fuel dump system installed. Accordingly, aircraft such as the Boeing 707 and 727, and Douglas DC-8 had fuel dump systems. Any of those aircraft needing to return to a takeoff airport above the maximum structural landing weight would simply jettison an amount of fuel sufficient to reduce the aircraft's total weight to below that maximum structural landing weight limit, and then land.
During the 1960s, Boeing introduced the 737, and Douglas the DC-9, the original models of each being for shorter routes, and the 105% figure was not an issue, thus they had no fuel dump systems installed. During the 1960s and 1970s, both Boeing and Douglas "grew" their respective aircraft as far as operational capabilities were concerned via Pratt and Whitney's development of increasingly powerful variants of the JT8D engines that powered both aircraft series. Both aircraft were now capable of longer duration flights, with increased weight limits, and complying with the existing 105% rule became problematic due to the costs associated with adding a fuel dump system to aircraft in production. Considering the more powerful engines that had been developed, the FAA changed the rules to delete the 105% requirement, and FAR 25.1001 was enacted stating a jettison system was not required if the climb requirements of FAR 25.119 (Landing Climb) and FAR 25.121 (Approach Climb) could be met, assuming a 15-minute flight. In other words, for a go-around with full landing flaps and all engines operating, and at approach flap setting and one engine inoperative, respectively.
Starlionblue From Hong Kong, joined Feb 2004, 15904 posts, RR: 66 Reply 21, posted (6 years 4 months 3 days 16 hours ago) and read 1830 times:
Quoting 747400sp (Reply 16): Wow ! How dangerous, any jetliner should be able to jettison fuel for safety reason.
I think you are assuming that fuel dump capability is installed to decrease the risk of fire/explosion during an emergency landing. This is not the case. If the plane is about to crash into the ground no amount of fuel dumping will change the situation.
It is installed to decrease landing weight for an emergency early in the flight. For a narrowbody, this is not needed. Also, a narrowbody can simply fly around and burn off fuel in some cases. This would take too long in a widebody.
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
HAWK21M From India, joined Jan 2001, 31228 posts, RR: 58 Reply 22, posted (6 years 4 months 3 days 3 hours ago) and read 1741 times:
Quoting TristarSteve (Reply 13): The B747 is partcularly prone to this on the ramp because as the wing bends down with a full load of fuel, the vent intake ends up at the lowest point in the tank! The wing rises during the take off roll so in flight it is higher up. (Never try and store fuel in here on a B747)
Wasn't there a Similar Incident a few years ago where Pax refused to fly an Airline after Fuel poured out of the Vents during Taxi Twice.
Quoting 747400sp (Reply 16): Wow ! How dangerous, any jetliner should be able to jettison fuel for safety reason
Quoting L-188 (Reply 19): any aircraft that has a MTOW heavier their the MLW is required to have the capability to dump fuel so that in an emergency it can make a landing at a weight below the MTOW.
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