What happens to airplane fuel that is dumped?

Aircraft must occasionally discharge fuel, but what happens during the process? When an aircraft must make an emergency landing, it must dump gasoline quickly. What is the nature of this process, and what occurs to the fuel? Let’s go exploring.

Which aircraft can discharge fuel?

Surprisingly, not every aircraft can discharge fuel. That is, there is no need for smaller aircraft like the Boeing 737 to be able to dump fuel when it can simply burn it off through a few orbits of the airport. If the plane needs to land quickly, the fuel onboard will not substantially impede the landing operations.

Larger aircraft, like the Boeing 747, have fuel jettison systems. If the aircraft attempted to land without first dumping the fuel, it would be deemed an overweight landing attempt, which could put enormous strain on the airframe. It may also increase the danger of fire and fuel leaking onto the tarmac.

However, airframe manufacturers designed these planes with these conditions in mind, so they usually have these overweight tolerances built in.

What occurs when a plane dumps its fuel?

When the pilots of an airplane decide to dump fuel at altitude, they flip a button in the cockpit, and pumps push the fuel out of nozzles in the wings. Because the fuel is dispersed over a large enough region, the particles evaporate into a fine mist. Essentially evaporating into a gaseous state and then fading into the background gases of the sky.

However, if an aircraft is at a low enough altitude, such as after takeoff, and disperses its fuel, it may remain in a liquid state until it strikes the ground.

As it is the equal of dumping thousands of liters of gasoline onto an urban area, the airplane will attempt to do it overland (rather than on water) or away from populated areas. The FAA expressly states that disposal is not permitted below 2,000 feet.

Worst-case situation, the aircraft isn’t high enough and must land over a populated area; the consequences are milder than you might anticipate.

The concept of ASSIST

When dealing with fuel dumps, SKYbrary emphasizes the following process:

A – acknowledge the emergency, inquire about plans, and provide information on suitable fuel dumping areas and altitudes, as well as landing aerodromes, as needed.

S – separate the aircraft from other traffic. (see next section). If a marked fuel dumping location exists, direct the aircraft to it. Ensure that the dumping happens at an altitude that will enable the fuel to evaporate/dissipate before it reaches the ground – 5000 to 6000″ AGL is usually sufficient.

S – Silence non-urgent calls (as needed) and use a separate frequency where possible

I – inform the supervisor and other sectors/units involved; notify the airport emergency fire rescue services and all parties involved in accordance with local procedures; notify other (uncontrolled) traffic in the vicinity using a general call, e.g. “All stations, [ATS unit], [TYPE] dumping fuel [level] [route or location]”

S – support the flight by giving any requested and necessary information such as approach type, runway length, and any additional aerodrome details, etc.

T – provide time for the crew to assess the situation, carry out the dumping process, and finish any necessary checklists. – Do not press non-urgent issues.

When Delta rained gasoline on a primary school?

In January 2020, a Delta 777 flying from Los Angeles to Shanghai experienced an emergency after takeoff and had to close down one of the engines. The aircraft was then forced to dump 15,000 gallons of fuel at a height of 2000 feet over a coastal city suburb. Unfortunately, it spread to three institutions, one of which was for young children.

Over 50 individuals were affected by the fuel dump, who claimed to have seen the plane pass overhead and then smelled a strong odor of fuel. Only after this point did they note their eyes burning, skin itching, and some breathing difficulties—fortunately, no other serious injuries.Since then, there have been cases. A guy claimed to be covered in kerosene.

We occasionally learn that an aircraft had to dump fuel before landing to reduce its weight. Although it does occur, gasoline dumping, also known as fuel jettison, is not a common occurrence. It is usually used in emergency situations where the plane must land sooner than expected.

Can all planes discharge fuel?

No, not all planes can discharge fuel. In truth, many aircraft, including the Boeing 737 and 757, lack this capability and, in reality, do not require it. However, Federal Aviation Regulations mandate certain aircraft, such as the Boeing 747, to have a fuel jettison system. The same is true for Airbus planes; the A340 and A380 can discharge fuel, but the A320 cannot.

Federal Aviation Regulations have precise requirements for dumping fuel and, as an alternative, overweight landings. After all, aircraft dump fuel to prevent overweight landings, which can cause significant damage to the airframe.

“Landing overweight and fuel jettisoning are both considered safe procedures,” according to Boeing. It is ultimately up to the pilot-in-command to decide if dumping fuel or landing overweight is the best choice, under the given circumstances.

How do planes discharge their fuel?

To dump gasoline, aircraft use their fuel jettison system. This mechanism is made up of various valves and pumps. The gasoline dumping is accomplished by pilots activating the system by flipping a switch in the cockpit. When the system is turned on, gasoline is pumped out through valves in the wings. This fuel is typically discharged into the atmosphere and evaporates.

Why do planes discharge fuel to reduce weight?

To begin, it is critical to understand that an aircraft’s maximum departure weight is always greater than its maximum landing weight. The difference is truly quite significant. Typically, an airplane that has just taken off for a long-distance flight will be considerably heavier than its maximum landing weight, owing primarily to the fuel aboard. If the aircraft must land soon after takeoff, dumping fuel will make it lighter and reduce stress on the aircraft framework and landing gear. Furthermore, it will enhance the aircraft’s landing performance.