Larger planes like the Boeing 747, on the other hand, have fuel jettison systems. If the aircraft tried to land without dumping the fuel first, it is considered an overweight landing attempt and could place immense stress on the airframe. It could also increase the risk of fire and fuel leaking onto the tarmac.
The exact fuel capacity of the Boeing 747 varies. However, on average most planes can hold up to 238,604 liters (63,346 U.S. gallons) of fuel.
In almost every case, any commercial plane flying is technically able to land even at close to its maximum takeoff weight. It will, however, likely put excess strain on the landing gear and other structures, so it's best avoided unless there's simply no other option.
Long haul aircraft such as the Airbus A380 and Boeing B777 are equipped to jettison fuel in emergency situations only. According to CAA guidelines fuel should be dumped over the sea or if this is not possible it should be above 10,000 feet to allow the fuel to evaporate before reaching the ground.
A captain has three choices when having to land quickly and overweight: Fly around long enough to burn the fuel down to the maximum landing weight, land with the plane still overweight or dump fuel. Depending on the situation, each option may be appropriate.
Fuel dumping (or a fuel jettison) is a procedure used by aircraft in certain emergency situations before a return to the airport shortly after takeoff, or before landing short of the intended destination (emergency landing) to reduce the aircraft's weight.
Airlines find that fuel dumping can actually be cheaper than not dumping in certain circumstances. But it's not something pilots do on a routine basis. We spoke with Alison Duquette, spokesperson for the Federal Aviation Administration (FAA), who assured us that it doesn't happen very often.
The MLW is set in order to ensure safe landings; if an aircraft weighs too heavy during touchdown, it may suffer structural damage or even break apart upon landing.
It would seem strange that pilots would purposefully dump fuel from their aircraft at a time when fuel prices have skyrocketed. What's more bizarre is that they do it in the air while flying. Tossing fuel into the air is a safe procedure for a good reason. Additionally, it is not as wasteful as it seems.
The reality is that the A380's fuel burn per seat is 2% lower than the 747-8's. The 747-8's cost per trip is just 12% lower than the A380's, while the cost per seat is 9% higher – the A380 is still the most fuel-efficient large widebody ever.”
Fuel is usually discharged to reduce the aircraft's weight to facilitate making a safe landing.
Fuel Capacity
Fuel tanks of large planes, such the Airbus A380 and Boeing 747-800, can hold up to 140,000 and 216,000 liters of gasoline, respectively. These aircraft are able to nonstop flight for as much as 16 to 18 hours, achieving as much as 15,000 kilometers.
Condensation in Exhaust Gases
As the airplane's engines release exhaust gases, moisture vapor is released as well. The cold temperature and low air pressure at high altitudes forces this moisture to condense, which creates the characteristic white smoke trail for which airplanes have become widely known.
4 November 1993: China Airlines Flight 605, a Boeing 747-409, ended up in water after it overran runway 13 at Kai Tak International Airport on landing during a typhoon with wind gusting to gale force. All of the 396 occupants donned life-vests, boarded the eight slide/rafts and no fatalities resulted.
With today's fuel prices, it costs about $450,000 to fill up a Boeing 747, depending on your market. By contrast, the Gulfstream G280, a popular business aviation aircraft, costs around $8,000 to fill.
Conclusion. While it's very clear that a 747 cannot fly properly with the failure of three engines, we can see that a single functioning engine would at least extend the aircraft's distance and prolong its time in the air. Hopefully, this would buy enough time and distance for the 747 to reach a suitable landing spot.
Aviation/jet fuel is not environmentally friendly because it emits CO2 and other chemicals that contribute to global climate change. Although there are ways to minimize its environmental impact, there are still many environmental drawbacks.
Also, not all planes have the capability of dumping fuel. But big ones like the 747, 787, or A380 can release it from their wingtips.
Although aviation fuels are sterile when first produced, they inevitably become contaminated with microorganisms that are omnipresent in both air and water. Microorganisms found in aviation jet fuels include bacteria, yeasts and fungi.
Like with water, adding heat to air separates the molecules and forces more space between them. Hot air makes it harder for planes to fly. Warm air expands and is less dense—it's why hot air balloons go up. It also means the air is thinner so it takes more power to get the lift that allows a plane to take off.
Bigger jets, like those made by Boeing or Airbus, can operate in hotter temperatures — specifically, the mid-to-high 120s. “All of our airplanes are designed and tested to operate in both extreme cold and hot weather conditions,” a representative for Boeing told Nexstar.
The most obvious is the waves. The larger the waves, the more dangerous the landing. Pilots try to land parallel to the waves, instead of across them, so the waves don't push the plane around, which could cause damage to the plane, injure passengers, and make evacuating more difficult.
Preventing overweight landings
The most common reason for aircraft to dump fuel is to keep them from landing above their maximum permitted weight. This will generally occur in instances when a flight needs to return to the airport shortly after departure.
So burning off fuel was the quickest way to bring the weight down under the maximum allowable for take off. Otherwise, the pilot could have just burned fuel in flight if the problem was simply too much fuel onboard for landing at a closer airport than originally intended for the aircraft.
Video shows Russian jet dumping fuel on US Reaper drone during 'reckless' interception over Black Sea. A former jet pilot tells Sky News the fuel dump was probably an attempt to down the unmanned drone but that the collision was almost certainly an accident.