Even if the fuel had been in the supply tanks and not the main tank, the helicopter would have landed back at base well below the mandated minimum fuel load.
From the report the fuel policy that was in place at the time was:
"2.1.3 Fuel policy
The PAOM Part 1 provides guidance for fuel planning, advising that fuel for
30 minutes at endurance speed (burning 170 kg/hr) should be included for a
flight over a non-hostile environment at night, in addition to fuel for start, run-up and taxi allowance, as appropriate, and the duration of the task.
At the time of the accident, the operator’s Operations Manual stated that the
Final Reserve Fuel IFR was 85 kg, with a Minimum Land on Allowance (MLA)
of 40 kg, and that:
‘Company policy is that the aircraft should not land with less than
60kg of fuel in the tanks.
If it appears to the aircraft Commander that the Final Reserve Fuel
may be required, a PAN call should be made. If the Final Reserve
fuel is then subsequently reached, this should be upgraded to a
MAYDAY.’
Since the helicopter had 76 kg of fuel on board at the time of the accident, the pilot might have been expected to make a PAN call, upgrading it to a MAYDAY on reaching the Final Reserve Fuel IFR, if he was aware of the fuel state. Again, due to the lack of evidence that might otherwise have been provided by cockpit voice and flight data recorders, the investigation was unable to determine the reasons for this apparent omission."
No surprise that with three different numbers in the mix there, that these policies were updated shortly after the incident to clarify:
"Following the accident, the operator amended their Operations Manual
procedure on fuel calculations, replacing the Minimum Land on Allowance
(MLA) with Final Reserve Fuel (FRF), and increasing the VFR and IFR/night
FRFs to 90 kg."
Now it's easy to sit in an armchair with a calculator and see that it is tight starting with 400kg and running for 1hr 40 (Both 3kg/min and 3.3kg/min have been used as quoted consumption figures, dependant on task type). But IF the display was stuck at 45/x/49 where x is some number, then it is not clear to me that the pilot would think that he is 'well below' any of those levels. What measure does he have other than the CAD display over rough mental arithmetic in his head to cross check?