sg38

The A320 has inner and outer wing tanks. There is fuel trapped in the outer wing tanks to reduce the wing bending moment by design. Fuel is used in the FADEC to cool the integrated drive generators (IDG) and to cool engine oil. Not all fuel is used by the engine and some is returned to the outer tanks. When each fuel content in the inner tanks is down to 1650 pounds, the content of the outer tanks are drained by means of transfer valves to the inner tanks for use. In addition there is a load alleviation function (LAF) on many A320 airplanes which relieves wing structure loads in turbulence by rapid movement of ailerons and spoilers 4 and 5. This scheme of design sums up the reason for the reduced wing flexing in the A320 series airplanes. Kurt Gamnig