Nick et al
The aim of the exercise is to quantify the effects on overall payload of changing the fuel planning to JAROPS 3 standards whereby you add 10% route fuel to the out and back calculation plus 30 mins res. At this stage I'm doing the equivalent of using the 10nm thumb that all helicopter pilots are equipped with and the numbers seem to work out at an overall reduction in payload of between 5% and 7%.
Next step is to find out just how accurate I need to be. If I need more than a 'good calculated guess' then I also have to get into how many of each type are in our overall fleet of nearly 50 machines and what the future (because we are talking future planning) fleet make-up will be. On top of that each fleet has it's particular mix of routes/payloads so the definitive calculation will of course feature Nick's suggestion to ensure lbs/nm are taken into account.
By the way has anybody come across a published explanation supporting this additional 10% route fuel? What was in the authority's minds when they ratified what had hitherto been a UK requirement?