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Centaurus
20th Aug 2014, 12:35
The B737-200 FCOM included under the Fuel chapter that the fuel gauge accuracy tolerance was plus or minus three percent of the total fuel gauge contents. It meant that when operating into fuel reserves where for example you were down to 1500 kgs total fuel before landing, allowance must be made for the worst case of three percent gauge tolerance. That worked out for the main tanks of around 130 kgs per tank. So you planned to land with an extra 260 kgs over and above the 1500 kgs.

Request information if the 737NG series and the 737 Classics have similar fuel gauge tolerance as I cannot find it mentioned in the FCOM. How about the A320 as well?

Also with regards to calculation of (say) 30 minutes holding fuel as the basis a fixed reserve, I recall that figure was based upon fuel required for an ILS from the Outer Marker - plus one go-around and a circuit inside the outer marker, touch down and full reverse. It was anticipated the engines would flame out due to fuel exhaustion on completion of he landing roll.
Can anyone verify if that is correct keeping in mind these figures were from the FAA many years ago.

FlyingStone
20th Aug 2014, 13:00
Check B737 Technical Site (http://www.b737.org.uk/fuel.htm#Fuel_Gauges) for fuel gauge accuracy.

According to EASA, final reserve fuel for turbine-powered aircraft is:

1.5. Final reserve fuel, which shall be:
(b) for aeroplanes with turbine engines, fuel to fly for 30 minutes at holding speed at 1 500 ft (450 m) above aerodrome
elevation in standard conditions, calculated with the estimated mass on arrival at the destination alternate
aerodrome or the destination aerodrome, when no destination alternate aerodrome is required.

BARKINGMAD
20th Aug 2014, 19:23
73NG guages accurate to +/- 2.5% when tanks are full.

For further info, track my thread on 73NG fuel guageing anomaly, sometime last year?