Slowing speeds to save on fuel costs

[CA1900]

Thanks for the good wishes, I'll need it!

Vanda did indeed leave us to work for an operator in Burlington. I'm sure the long commute (lol) must have worn on her. Henry W. is now our D.O.

 

[Flying Illini]

THANK YOU DIESEL!!!

Let us theorize an average fuel burn saving per hour of 300# total with an average speed impact in still air of 25 KTAS reduction.

In a 250 KTAS aircraft this is one additional tenth ".1" flight time.
If this 250 KTAS a/c costs $750 per hour to operate, this equates to increased cost of that flight by $75.

300# of fuel or 45 gallons (rounded) with an average increase (last year) of 75 cents per gallon is only saving ON GAS $35 dollars per hour, BUT increasing the overall cost of the flight by that $75 from more time on the a/c.

You would have to be paying over $2 per gallon ABOVE normal in order break even on the offset in increased operational costs. This is true for any Corporate/Charter Aircraft. Higher speed, higher fuel burn will incidentally have higher operational costs and inversely lower performance the more the fuel flow is reduced.

100-1/2

It's refreshing to know I'm not the only one who thinks like this...wish I had the power to effect change, but that happens at a pay-grade much higher than mine.

 

[AutoBus]

High Altitudes worked great for me, FL220 from ALB to ROC Fuel flow set to 350pph (no specific torque setting) per side at cruise and climb at the recommended climb schedule. total burn about 700 pounds. Same holds true for BOS to BTV etc.. and generally speaking don't worry about the headwinds, your trade off point is about 3 knots of headwind per 1000' of altitude, in otherwords I would have gladly accepted a 65 knot headwind at FL 220 instead of a 40 knot headwind at 8000

Several months ago, our company (CommutAir) issued new a new normal cruise power setting in an effort to save fuel. (On our Beech 1900s, we've gone from 3000# and 1450RPM to 2750# and 1400RPM.) In principle, it's worked great. It's saving our company significant fuel and money. But it could save so much more.

On legs that are properly blocked, I'm happy to do it. But on legs that are blocked too short, I don't slow, because our passengers are making plans around that schedule. When I'm swapping airplanes at the next station on a short turn, I don't slow. Our training dept. has noted that, after several months of declining per-hour fuel usage, it's starting to go back up, which I attribute to inadequate block times combined with short turns. Don't make me eat into my lunch break.

 

[AutoBus]

THANK YOU DIESEL!!!

Let us theorize an average fuel burn saving per hour of 300# total with an average speed impact in still air of 25 KTAS reduction.

In a 250 KTAS aircraft this is one additional tenth ".1" flight time.
If this 250 KTAS a/c costs $750 per hour to operate, this equates to increased cost of that flight by $75.

I'm affraid it's not quite that simple, because you don't buy the things that equate to aircraft operating expenses by the hour or even a tenth of an hour. Most of the elements that effect the $750/hr cost you quote are purchased annually, so things like insurance, pilot training, buying the aircraft, hangar space, admin staff and maint are fixed expenses and therefore flying an extra .1 a trip does not really cost you ANYTHING, bottom line saving fuel saves you money. Taking that a step further it could be argued that running the engines cooler will increase the life of the engines and where there is a fixed TBO it will decrease the overhaul cost.

In a nutshell the $750 an hour is not an absolute figure, it's a planning number based on the number of hours you expect to fly the aircraft. If you only fly the aircraft let's say 10 hours a month you might have to work with a number of $6000 an hour. If you increase the number of hours above what you are flying now, let say 30% you would expect to see the hourly rate to drop to maybe $650 an hour.

 

[AutoBus]

Hey where the hell is my ESOP money?

QUOTE]

I'd settle for an ESOP statement, where the hell is the ESOP money? I guess we are still waiting for the IPO?

 

[cezzna]

A big benefit to flying higher mostly and slower is the eventual harm to the enginges. I've talked to several mechanics who say there is a big difference at overhauls in what needs to be replaced. The higher and slower you go the lower the ITT's and it can make a big difference. I know of companies that extend their TBO's based on proof of this. i'm not saying it's right but it does add to the equation.