Have you ever looked up and saw an aircraft flying with long white lines like gas behind it ? Iâ€™ve seen it many times and what the aeroplane is doing is called fuel dumping. Now youâ€™ll be wondering why pilots will dump fuel considering the fact that aviation fuel is very expensive and also causes serious pollution to the environment. In this post techcapon be explaining to you why it is necessary for the pilots to dump fuel sometimes.
Now this also includes our local airlines in Nigeria like DANA, AERO etc. Although fuel dumping is more common with airlines that travel long distances and make international flights. Before take-off, the airline do the maths. They calculate how much fuel is needed to the aircraft to complete their journey and they fill the aircraft tanks with enough fuel to make the complete their journey. There are some terms Iâ€™ll like to explain in this post for you to understand how it works.
Dry operating weight: This is the weight of the plane without fuel, passengers or luggage.
Payload: This is the weight of the passengers and their luggage
Zero fuel weight: This is the weight of the fuel needed to reach their final destination including reserve.
Dry operating weight + Payload + Zero fuel load = Take-off weight
Take-off weight MUST always be greater than landing weight
The major reason why pilots dump fuel is because the landing weight of the plane exceeds the maximum. Inside the cockpit, pilots have a meter that tells them the weight of the aircraft at all times. For example, Boeing 747 aircrafts have a maximum landing weight of 312000kg.
Anything above that weight will cause the aircraft to suffer serious damage during landing or even crash during landing. Infact, if the maximum take-off weight is above 312000kg, the cockpit will blink red lights and give the pilots warning. The question on your mind right now will be, if the airline calculates how much fuel is needed to arrive their destination, why dump fuel before arriving ? The answer is simple.
For example, a plane thatâ€™s suppose to fly from Lagos to New York city loads enough fuel to reach their destination. Everything is going fine then suddenly a pregnant woman who is on board goes into labor. If thereâ€™s no nurse on board and the flight attendants cannot handle the issue, the only choice will be to make an emergency landing.
The flight crew will alert the pilots on the situation and the pilots will have to land in the nearest airport. The first thing the pilots will check is the weight of the aircraft. For an aircraft that has enough fuel to reach New York, of course the landing weight will be far above normal. In this scenario, the pilot must dump enough fuel in order to reduce the weight of the aircraft before landing.
The pilots have no choice. There are 3 things that add weight to an aircraft. Passengers, luggage and fuel. Obviously the pilots cannot dump passengers. Neither can they dump cargo (except in very rare cases), the only option is to dump fuel.
The pilot will dump the fuel, make the emergency landing in order to get the pregnant woman to the hospital, refuel before they can continue the journey. Of course dumping fuel is a big loss to the airline companies. They lose big money anytime these things occur but itâ€™s better to dump fuel than land an overweight aircraft thereby damaging the aircraft or jeopardizing the lives of everyone on board.