Auxilliary Fuel Tank

BBJ (Boeing Business Jet) can travel longer range compared to conventional 737 due to this extra fuel tank added in its cargo hold.

Depend on certain configuration per customer specific need, this extra tank can be placed at aft area of the forward cargo or forward area of aft cargo hold. This is to ensure center of gravity of the aircraft remain close to the center of the aircraft.

Each tank can hold around 1800 liters of fuel which if converted to kilograms will be around 1500 kg except the master tank which will have much higher capacity.

All fuel from auxiliary tank will be routed to the center tank of the aircraft before goes to the engines. What unique about this system is, fuel from auxiliary tank is "pump" to center tank using differential pressure from the cabin which will start once fuel in center tank dropped to certain level.

During initial refueling before the flight, the fuel will be added to the wing & center tank fuel first, extra fuel required for the flight then will be filled up in this auxiliary tank.

It's hard to see how this aux tank looks like, i found this extra tank kept in the store, it has been removed form one of the BBJ due extra cargo space required for the baggage. if you need extra range for the distance, cargo space has to be sacrifice for the fuel tank...