Smarter fuel system

The Airbus A320 NEO is visibly different from its predecessor, the CEO. The difference however, is not limited to what meets the eye, it isn’t just the big beautiful P&W engines and the fancy sharklets. The NEO also gets modification in various aircraft systems; fuel, F/CTL, pneumatic,  to name a few.

Now, I particularly liked the changes they made in the fuel system.The prime focus has always been to reduce weight, increase robustness of any system on the aircraft. In case of the fuel system, they have always wanted to ensure fuel feed segregation during critical gases of the flight i.e. Take off and landing, and that the CTR TK fuel is consumed first.

To ensure that fuel feed segregation happens during the critical phase of the flight and that fuel from CTR TK are consumed first they put a logic in place :

• Fuel from the CTR TK is consumed first
• Whenever the slats are extended, which they are for T/O or landing, the CTR pumps stop to ensure that fuel to engines is supplied from their on side tanks. 

However, if both the CTR TK pumps were to fails, the CTR TK fuel would be unavailable for the rest of the flight. Keep in mind that the CTR TK do not have gravity fuel feeding. 

Let’s look at the NEO now. I am not sure if the above reason was why the good folks at airbus decided to get rid of the CTR TK pumps, but they sure did get rid of them while ensuring that the two things they expect from the fuel system ( segregation and CTR TK priority of consumption) were still in pace. 

The NEO, instead of electrically operated booster pumps in the CTR TK, has mechanical Jet pumps which create a Venturi and move the fuel from the CTR TK to the Wing Tanks.  The working is quite simple and will make sense to you if you have ever used a pipe to take out fuel from car or bike tank . All you need is that initial suction and once that is done , the fuel keeps flowing without your intervention. The same principle, more or less, is used here.

The center tank fuel transfer is done by the Fuel Level Sensing Control Unit ( FLSCU). When the transfer valve is open, the fuel from inner wing tank flows though the jet pumps creating a suction which moves fuel from the center tank to related inner tank.

In case the inner tank gets full, the transfer valve close until 500kg of fuel has been used from the inner tank. Once that is done, the transfer valve opens and the suction is created which again moves the fuel from the center tank to the inner tank. 

This not only reduces weight ( fewer pumps) , increases robustness but also ensures that fuel  segregation is always active and that the center tank fuel is consumed on priority.

*Disclaimer* Data and information presented in the blog should not be used for practical purpose, it is only for understanding. For real life scenario, kindly refer to your company manuals ( FCOM, FCTM, Ops Manual). Also, the images added on the blog are not owned by me and are picked up from the net.