Originally Posted by
alfasprite
We've been operating two new H145 T2's since early May and have had the same fuel indication issue on both aircraft throughout. The fuel amount for a full main tank has varied from as little as 677 kgs, up to a maximum of 712 kgs. Our Engineers have been working hard to figure out what the issue is. At first, it was thought it was the 'age old' 145/117 ball valve, slope of the ground issues etc. However, with both aircraft indicating the same main tank fuel amount after refuels on the same day, (within 1-2 kgs) the feeling was the issue was being caused by something else. After multiple defuels and refuels, where, by the amount supplied via a fuelling truck, they could guarantee that the tanks were full to the max possible (as stated in the RFM by Airbus), our engineers narrowed down the issue to being caused by a change in the specific gravity of the fuel being supplied to us. When the refuel company informed us that they were using a new batch of fuel, the fuel SG had changed when checked and the maximum amount indicated in both our aircraft main tanks changed too! The SG has varied from 0.775 up to 0.795. Airbus are aware of this issue elsewhere in the world and are sending out an engineer next week, to train our engineers on how to recalibrate the main tank fuel probes. We're told that airbus are working on a permanent fix?
Pain in the arse when you need a certain amount of fuel to be indicating on TEMPO days!
Hope this helps?
Ok, I’m going to stick my head above the parapet and look stupid, possibly, but where is the volume to weight calculation being done? I thought the capacitance probes simply send volume information, and the SG to weight calculations are done in the VEMD (same with fuel flow - metering valve position equals volume flow rate equals mass flow rate for an assumed SG).