PT6A
I would be curious to the "briefing" that BA provide its pilots.
Scratches head and tries to remember something he was told a long time ago, so forgive me if I've got this wrong: as far as I recall it the logic behind C.I. zero for the climb was to give a quicker climb to cruise (
) verses a non zero CI, and therefore you reduce engine costs (I believe paying manufacturers for "power by the hour" comes into it). Apologies again if that is BS, but that certainly was the story I've heard regarding climb C.I., I'd welcome other thoughts.
Tonic Please
So it seems that you don't have an official CI for a flight, so my question is: How do you know what CI to put in when you want to modify your ETA/Cruise FL? Is there a graph to look at? A data sheet of some kind? Or do you guess and say "Oh well CI80 is giving us FL360 and ETA of 1645, let's try, erm, 45 and see what that does"? I'd be surprised if that were the case?
Tonic -I'm surprised that you are surprised, because that is pretty much what we do....i.e. try changing the CI, see what that does to ETA/Fuel and modify the plan accordingly.
I suppose we
do have what you could call "official" CI for each sector, it's detailed on the front page of the fuel plan we run off at briefing. If you've got very favourable winds you'll be presented with a CI zero plan (and also low fixed Mach numbers for Oceanic portions of the flight), if you've got unfavourable headwinds you'll have a high CI plan (and higher fixed Mach numbers over any ocean). If it's a high CI plan you're also given the fuel and time gain for CI zero as a note at the bottom of page one of the plan.........
however.... the company policy is that the CI/Fixed Mach portions of the flight can be varied
by the crew during flight,e.g. to try to achieve a punctual arrival. The flight planners in the office can't factor everything into the plan and come up with a perfect CI. Just one example - an off schedule arrival can incur extra costs for the airline (e.g passengers missing connections), and stand plans (yes we do have one!!), ground handling personnel allocation and the like can be ruined if we arrive very late or very early at the likes of LHR, so being flexible with the CI once airborne is an official policy.
... your company would be a little miffed if you changed it en-route since they fixed it to adhere to their own fuel policies/prices for that day of weather... the route planning chaps, etc.
No my company wouldn't be miffed at all - see previous comments. Yes, on an ideal day you depart on schedule and fly the planners plan
, but there would certainly be adverse comments on a Long Haul line check if you departed late, and then, despite fuel in hand, let the CI sit at the planned value for hours, and as a result arrived late at destination simply because the planners had said fly at CI X
.
I'd be surprised if we were the only airline that had such a policy, fortunately we're not complete slaves of the machine, .........yet.