Many of these flights were fuelled for travel well into the American interior for those mid-flight aircraft unable to land due to excessive fuel weight, dumping was necessary. were either turned back to their point of origin or diverted to land in Canada and other countries. International flights en route to the U.S.
airspace was closed due to the September 11 attacks.
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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.Ī large-scale fuel dumping occurred on September 11, 2001, when U.S. Considering the more powerful engines that had been developed, the FAA changed the rules to delete the 105% requirement, and Federal Aviation Regulations 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. 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. During the 1960s and 1970s, both Boeing and Douglas "grew" their respective aircraft as far as operational capabilities were concerned via Pratt & Whitney's development of increasingly powerful variants of the JT8D engines that powered both aircraft series. Any of those aircraft needing to return to a takeoff airport above the maximum landing weight would jettison an amount of fuel sufficient to reduce the aircraft's weight below that maximum landing weight limit, and then land.ĭuring the 1960s, Boeing introduced the 737, and Douglas introduced the DC-9, the original models of each being for shorter routes the 105% figure was not an issue, thus they had no fuel-dump systems installed. Aircraft such as the Boeing 707 and 727 and the Douglas DC-8 had fuel dump systems.
If an aircraft lands at more than its maximum allowable weight, it might suffer structural damage or even break apart on landing.Īs jets began flying in the US in late 1950s and early 1960s, the FAA rule in effect at the time mandated that if the ratio between an aircraft's maximum structural takeoff weight and its maximum structural landing weight was greater than 1.05, the aircraft had to have a fuel-dump system installed. If a flight takes off at the maximum takeoff weight and then must land well before its destination, even returning immediately after takeoff to the departure airport (for example, because of mechanical problems or a passenger medical problem), it will contain more fuel than was intended for landing. It is the abnormal, non-routine flight where landing weight can be a problem. This allows an aircraft on a normal, routine flight to take off at the higher weight, consume fuel en route, and arrive at a lower weight. Aircraft fuel dump Weight issues Īircraft have two major types of weight limits: the maximum takeoff weight and the maximum structural landing weight, with the maximum structural landing weight almost always being the lower of the two.