Clarification - Fuel figures

Started by MikeS, January 10, 2020, 01:22:42 AM

MikeS

I am experimenting with an IL-62 and having a detailed look at some figures:

Analizing flight MC509/510 (DotM) MEX-JFK-MEX service (1817nm):
Flight time to JFK is 4:21 at 1843nm still air distance while back to MEX it is 4:56 and 2122nm
So the flight back is 15% longer and takes 13.4% more flight time (35min)

The fuel cost difference, however is 27%: $28373 vs $22340
What am I missing here? Does AWS account for the fact that the total fuel upload would be higher and the aircraft heavier? Still
the difference seems too high, no? It should be closer to 15%. The flight distance is well within the aircraft's performance specs.

JumboShrimp

Extra fuel that is needed for the return trip is extra weight, which in turn causes higher fuel consumption.

Also, it appears you are carrying more passengers on the return trip, so, again, more weight, higher fuel consumption.

MikeS

Not carrying more pax on return leg. Revenue is higher due to higher ticket prices (outbound flight is overnight so I reduced prices a bit)

stealy

#3
Could it be due to headwind vs. tailwind? I think wind direction was implemented to the sim not too long ago. So headwind = higher fuel consumption?

(Just a guess tho... I am not sure.)


Edit: Also, I don't think lowering prices make any difference in LF, at least not noticeably. I actually raise prices 5-10% above suggested.

MikeS

Yes, the head wind makes the journey ~15% longer as originally stated and that translates into higher fuel consumption. My question was whether it is reasonable to suggest 15% longer route uses 27% more fuel. I believe the difference is too high as the flight was well within normal operating performance of the aircraft (the closer to the maximum operating range the more inefficient a flight becomes).

Anyways, that flight was a test flight only. I have a set of 7xIL-62 on order and will check the figures on those when they are scheduled.

Cheers!
Mike

LemonButt

If I am not mistaken, the price for fuel is different at each airport--the values you see in fuel management are simply averages.  Thus, it wouldn't be unreasonable to think the prices are significantly different between the US and Mexico for that route.

LemonButt

Additionally, you probably have a fuel contract at your base that would make these values cheaper one-way?

MikeS

Quote from: LemonButt on January 11, 2020, 08:46:53 PM
Additionally, you probably have a fuel contract at your base that would make these values cheaper one-way?
You are right, haven't thought about that: I have a -7.4% fuel contract at my home base. That must be it. Thanks a lot, now it makes more sense!

Love ya!
Mike