The quick fuel draining system (called Fuel Jettison) is an onboard system in large aircrafts like B747, B767, B777 and some B757 and also A330 and A340.

When an emergency procedure around an airport is carried out, the airplane must be able to land with the Take Off Weight (sometimes Maximum Take Off Weight). Then, the low/mid range airplanes have no problems dealing with that, but long range airplanes does.  

Heavy airplanes usually carry a huge amount of fuel (because of long haul flights). Thence, according to JAR regulation JAR 25.1001 about Airworthiness, these heavy aircrafts must be equipped with a Fuel Jettison system. The regulation require to the system to empty the tanks in 15 minuts, and then leaving enough fuel to keep a 3.2% climb gradient in landing configuration at 1.15 stall speed. For example, a B727 releases 1060 kg (2330 lbs) of fuel per minute, with all tank pumps running. The fuel nozzle is set at the wing tip, in order not to make any damage at the airplane fuselage. 

    Source: Wikimedia

Even though this procedure seems pretty enviromentally harmful, it isn’t much critisized because its low frequency, low amount of sprayed fuel and the procedure conditions. If possible, fuel jettison procedure must be done over the sea.

The ETOPS (Extended-range Twin-engine Operational Performance Standards) defines the twin-engine aircrafts requirements to operate flights where the nearest enroute alternative airfield is further than 60 minutes.

At the beginning of commercial aviation, because of the lack of regulations concerning alternative airfields further than 60 minutes, the air carriers started putting pressure on Aviation Administrations to be modified,  in order to be able to operate transatlantic routes with twin-engine. Because of that, ICAO and the FAA drawn up a new reguation that allowed to operate those routes. 

Nowadays, there are several ETOPS ratings depending on some parameters. These parameters are including the engines and systems’ reliability, crew training and ratings, manteinance and so on.

Author Andrés Meneses

These are the different ETOPS ratings issued these days by Aeronautical Authorities:

• ETOPS-75
• ETOPS-90
• ETOPS-120/138 (138 minuts is a 15% plus 120 minuts, in order to cover a little part of the Atlantic Ocean, not covered with ETOPS-120)
• ETOPS-180/207

An ETOPS rating is gradual. That means if you want to reach ETOPS-120 rating, first of all the aircraft must have reached the ETOPS-75 rating (with 200 sectors with 98% relieability), then the ETOPS-90 rating (with 300 sectors with 98% reliability), and finally the ETOPS-120. For example, in order to achieve ETOPS-120 rating, the airplane must prove less than 0.05 per mil in-flight shut-down. That means, flying 20.000 flights there’s only one in-flight shut-down (obviously, an airplane does not achieve 20.000 routes in its life).

There’s a tremendous application called Great Circle Mapper where you can compute each ETOPS rating maximum range around the earth.