737NG: ctr tank & density error?
Fairly new to the 737NG and was wondering about the following:
Common technique in my company is to increase the desired uplift of fuel by 100-200kg due to the fact that ~200kgs will be "lost" as soon as the CTR tank is empty inflight. Fine to me, but nobody seems to have a reasonable explanation for this. I've heard several talking about an error in the density sensors of the tanks, others mention the fact that this technique only applies when the fuel at the point of departure is hot due to high OAT....
There's nothing in our books about it... could anyone shed some light on this for me? Why is there an error in the fuel qty indications and what exactly does it have to do with the ctr tank and/or the density sensors?
thx in advance
tadex