Flying slow to save fuel?

[mamba20]

Question: Why are we talking about indicated airspeed while at FL300? Thats the mach region. Of course your indicated speed is going to be around 250. As far as flying slow to save fuel? As long as your ontime or early there is nothing wrong with it. You never know when you might need that extra gas and take a good close look at the difference in flying at MMO as opposed to flying and a more economy cruise speed. More often then not you will find that you burn WAY more gas to go fast and no make up much time at all.

 

[aewanabe]

Sorry PCL, but I'm gonna fly whatever speed I want on the busy airway (after advising/asking ATC, of course, since my speed and ETE are deviating from what's filed). If that's holding up the flow then center is perfectly capable of asking me to speed up, taking some delay vectors to get somebody else in front.

 

[PCL_128]

Sorry PCL, but I'm gonna fly whatever speed I want on the busy airway.

Fine, be a d0uchebag.

 

[aewanabe]

Fine, be a d0uchebag.

Yeah great job with the partial quote. Did you miss where I advised center of the change or are you just trying to be a jackass?

Seriously, when I was a CHQ captain I was often flying my jet at .63-.67 when we were 30 early, because that's what the book said the most efficient speed was- imagine that. Now what do you suppose would happen when Citrus or Southwest or anyone else came burning up my ass on the airway? Wait for it, wait for it..... Oh yeah, the center controller would speed me up or vector me off the airway depending on what he needed. Seems like it's my job to fly the aircraft efficiently, and his job to manage traffic. Works good lasts long time.

 

[Raskal]

Fine, be a d0uchebag.

What's with the hostility? Why do you give a f%ck what anyone else flies at? As for being held up, request vectors/alt change around, and if you don't get it than it probably wont help anyway.

FYI-.01 mach=6 mph (approx) so, newsflash, it wont make more than a couple of minutes difference for a shorter leg anyway. Relax.

BTW, if you're in such a hurry than take a bit of advice and get out of 121, cuz it's only getting slower.

 

[relief tube]

What's up with some of the regionals flying slow to save fuel these days? Do they NOT want to get to the destination asap? A CHQ was doing 250 over the ground at FL300 the other day on his way to IAD, and had his speed pulled back to "conserve fuel" wtf, is this a company directive?

Why do you think it's only regionals? Majors do it too.
That's why everyone is asking for higher.

Do you live in a cave? B/C it seems like this is a new thing for you.

Fuel prices are up 300%, and this world's ecosystem is going down the sh-i-t-ter.....if we slow up we help minimize the impact of both.

I religiously fly slow if we're showing early, and will do so for the rest of my life...why get in 10 minutes early for a 2 hour sit? And I'll be the first to offer to go faster if we're slowing someone up behind us, except if it's Gojets.

Maybee you should think of doing the same, instead of being busy not knowing about much.

 

[dickburns]

hey unstable aviator, what makes you think I was behind you? I wasn't. but your company was doing it again yesterday. rofl.

 

[dickburns]

hey BoilerUP, airlines have hedged their fuel THAT WELL, that they're paying $2.25/gal? That sounds very cheap. Impressive.

 

[BoilerUP]

hey BoilerUP, airlines have hedged their fuel THAT WELL, that they're paying $2.25/gal? That sounds very cheap. Impressive.

Airlines buy massive volumes, obviously getting them a discount.

For the 3rd quarter that ended Sept. 30th, US Airways (ticker LCC) paid an average of $2.22/gal of Jet-A, using 311.3M gallons of fuel. Fuel Hedges provided US Airways with $20M in savings.

For comparison's sake, Southwest (ticker LUV) paid an average of $1.69/gal for Jet-A over the same quarter, using 388M gallons of fuel. Hedges provided LUV with $188M in savings for the quarter, and without them fuel would have cost LUV $2.12/gal.

Basically, SWA paid $.53 per gallon less than US Airways for fuel for between July and September.

 

[Propsync]

I can't speak for every operator out there, but engine mx can affect slowing down. Power by the hour means go fast and save on engine mx cost, but burns more fuel. Obviously, the opposite is true. Since I have no idea of what mx costs are for engines on a per hour basis, I wonder what scenario is better, and by how much.

 

[PCL_128]

Now what do you suppose would happen when Citrus or Southwest or anyone else came burning up my ass on the airway? Wait for it, wait for it..... Oh yeah, the center controller would speed me up or vector me off the airway depending on what he needed. Seems like it's my job to fly the aircraft efficiently, and his job to manage traffic. Works good lasts long time.

Sometimes he'll do that, or sometimes he'll just slow down the people behind you, which seems to be the more common solution from most controllers. If you're flying on busy airways with people behind you, then you need to be flying your flight planned speed.

 

[time builder]

I can't speak for every operator out there, but engine mx can affect slowing down. Power by the hour means go fast and save on engine mx cost, but burns more fuel. Obviously, the opposite is true. Since I have no idea of what mx costs are for engines on a per hour basis, I wonder what scenario is better, and by how much.

There can be MX savings in going slow. We use a reduced power setting on our turboprops to not only save gas, but it also saves on compressor washes and hot section inspections. Not to mention turboprop engines going over 20,000 hours without a major overhaul, the effects of running at a lower temperature can be more important than the time accumulated on the engines.

I know my company is considering reducing power settings even more. My personal opinion is that if you can catch a tailwind, pull the power back and milk it (particularly if you're running ahead of schedule and you know your ground crew won't be ready for you anyway), if you're encountering a strong headwind, you're only prolonging the time spent battling the headwind and not saving much fuel, heck, that's 9th grade algebra.

Another thing I don't get, why do some people insist on taking a delay vector over a speed reduction. I can just see my coworkers scratching their heads when I request a speed reduction after getting a delay vector (as if I'm just asking for punishment), but then they almost immediately vector me back on course and I arrive at the same place at the same time having burned less fuel.

That, and if something opens up (the C208 ahead switches routing, or one of your other freight dog friends cancel IFR, for instance), you have less distance to cover being on your original course, and you might get there sooner.

 

[BoilerUP]

Flex thrust climb to 10,000 also keeps engine temps lower, and therefore hot section inspections cheaper and engine time on pylon longer. I think it also saves a bit of fuel, though that isn't the primary motivator...

 

[SBD]

To the CMR folks, I don't know if anyone knows the JFK FO who did his own independent study of PPAS v.s. flying at .77. It turns out that flying at .77 actually saves more fuel than flying the PPAS profile. I only heard it second hand so it is probably not true, just wondering if anyone has heard about it.

 

[5ontheglide]

yup just like everyone else said, more money in your pocket, saves the company money, and you dont have to sit on the ground for 20minutes waiting for a gate to open. but agreed if you are holding someone else up pick it up and get out of the way

I'll take a vector to let whoever is in hurry get by us. My goal is six minutes extra per leg. For me it averages out to $40-50 extra on a 4day trip. I can cover my food bills on that! Yes I eat cheap and pack snacks. Out early and arrive on time baby!

 

[SKYWRJGUY]

2 cents:

I use the VNAV page to see if slowing actually saves any fuel on the proposed profile. Many times I have noticed the increases inflight times nearly offset lowered fuel flows, so it's a push--lower fuel flow doesn't equate to less overall burn. On longer legs, I've actually played around and had higher burn at lower speeds--too slow and you get on the back side of the power curve. At 250kts the -700 burns ~3000lb/hr at any altitude, and when we slow to a clean holding speed (i.e. 210 or so), the fuel burn comes back up to around that number.

If you're that early, land and then shut down an engine [both if on the power-by-the-hour program] and leave the APU off (-700); at 450-500pph, that 15 minutes early on the ground translates into 100+lbs .

 

[PCL_128]

Flex thrust climb to 10,000 also keeps engine temps lower, and therefore hot section inspections cheaper and engine time on pylon longer. I think it also saves a bit of fuel, though that isn't the primary motivator...

It actually burns a tiny bit more fuel (extra time spent at lower altitude), but the engine mx savings under most mx programs more than makes up for the extra fuel burn. We use de-rated climb power on almost every flight. Saves a ton of money on mx. I wasn't aware that any RJ operators had a FLEX climb program going, but GE did put out some documentation on it.

 

[BoilerUP]

AWAC went to it about 8-10 months ago in their never ending quest for lower engine MRO expense. It supposedly has helped put our engines' reliability even further at the top of the list of CF34 operators (along with restricting use of TRs, no single engine taxi, etc).

Guess they were following AirTran's lead...we both get yelled at departing PHL for flex climbing! :laugh:

 

[PCL_128]

Guess they were following AirTran's lead...we both get yelled at departing PHL for flex climbing! :laugh:

I solve that problem by avoiding PHL as best I can. Guess you can't do that, though.

 

[SSDD]

Skywest has been doing FLEX takeoffs for about 7-8 years.