Jungle Jet and CRJ speeds

[NJA Capt]

The company will not spend the money on extra fuel and wear and tear on the engines for the minimal gain of flying a few knots faster.

Engines TBOs are based on hours flown. If a flight is flown faster, there is less time placed on the engine/airframe. As long as the engines are run at M/C or less (temps etc), there is no harm to the engines. Especially on the engines that are derated so much. Trust me, those AE3007s love flying above .91m
And fuel flows above FL410 are less than 1000pph/each.

Slowing to .84 is like doing 45mph on the interstate.

I agree, you're not going to save much time between .74-.80, you just burn a little more gas. Where if we slow from .90 to .82 it adds substantial flight time.

For the record, our flight crews share operational control of each flight.

 

[DoinTime]

Engines TBOs are based on hours flown. If a flight is flown faster, there is less time placed on the engine/airframe. As long as the engines are run at M/C or less (temps etc), there is no harm to the engines.

This may be true in the world of business jets but doesn't hold true at airlines and their continuous maintenance system. Engines are modular and built into sections that can be replaced independent of the rest of the engine. The "hot" section, which includes the combustion chamber and turbines, is the most frequently replaced and I believe replacement intervals is determined by trend data and visual (boroscope) inspections alone. There are reasons why we (airlines) do flex takeoffs and aren't flying around at max continuous. High temps are the number two engine killer right behind FOD.

 

[NJA Capt]

This may be true in the world of business jets but doesn't hold true at airlines and their continuous maintenance system. Engines are modular and built into sections that can be replaced independent of the rest of the engine. The "hot" section, which includes the combustion chamber and turbines, is the most frequently replaced and I believe replacement intervals is determined by trend data and visual (boroscope) inspections alone. There are reasons why we (airlines) do flex takeoffs and aren't flying around at max continuous.

Actually, we are under continuous mx programs too. Everything is still base on flight time. Trend data is used to spot problems before the inspection interval (time). No-one is going to split an engine open before they have to without just cause (trend). Nothing is usually replaced during a hot section unless it is out of tolerance (condition or AD).

I'm not too familiar with flex T/Os, but I imagine noise and fuel played a big part in it too. I know it did on the 727.

Our engines are derated from the ones the ERJs use (around 8000# ?) to approx 6700# each. They don't have to work very hard and stay pretty cool also. But, airlines use an airframe for 50,000-100,000 hours, where a corp jet isn't used much beyond 10,000. (Our highest Ce750 airframe might be 4000 hours, TBO is 6000)

 

[Jet_Dreamer]

this is just an observation: to all who fly their planes fast.

why not fly the company recommended speeds or slower. by going faster you just taking money out of your pocket. sure, as fast as you can go is cool, but i will get you there 10 minutes later and a few extra bucks in your pocket.
peace!

 

[efiscompmon]

Also, you say "in the manner the company wants." I would think the company wants the customers to be happy so that they return

Heh. You don't work for NWA!

 

[PCL_128]

For the Pinnacle guys...

The Pinnacle FCOM and FOM do not contain climb/cruise/descent speed profiles. The only time the FCOM mentions specific speeds that must be flown is on departure and approach.

On the climb for instance, take a look at your FCOM II. It lists 3 different speeds: 250, 290, and 310 kts. It states that these speeds are recommended speeds for different flight conditions: fuel saving, normal, and high-speed climb. Nowhere in the FCOM does it state that these speeds are mandatory. It says they are recommended.

For that matter, the FCOM II does not mention any speed AT ALL for cruise. Not a single speed (even recommended) is listed. The only place that states .74 is the cruise speed is on the release. That's not a profile, that's a flight plan speed. You can always fly faster or slower than the plan speed. Nothing in the FCOM mentions that you must follow the flight plan speeds.

For the record, I fly .74 in cruise 99% of the time to save fuel. I don't much like arriving within a couple hundred pounds of decision fuel. However, stating that we have a cruise profile is incorrect.

 

[SkyWestCRJPilot]

I generally agree with those that fly the profiles but I have some exceptions with the profiles at SkyWest. We are planned at 290 in the climb to .74 often. If we had pushed early I would climb at 250 and then go as high as possible (often 4000 feet higher than planned) go .74 and descend in the fuel conservation profile. It's so funny to see pilots who taxi on one engine to save fuel, and then climb at 290 in a tailwind, fly 4000 feet below max capable (because that's what filed) and fly .80 in cruise. Doesn't make any sense. The fuel savings on a single engine taxi is around 100 lbs. By climbing at 250 and going higher in cruise and flying .74 you'll save around 400 lbs on a 1.5 hr flight with the addition of only about 3-4 minutes to block. Interestingly it's more fuel efficient at FL 350 at .77 than FL310 at .74 (It's even better at FL 350 and .74 as well.) Altitude is a huge factor on fuel savings and so few people go higher than planned that it boggles me sometimes.

 

[Russ]

Just be careful about that 250 profile. You got the same E mail I did about profile speeds. Company and FAA would rather us play nicely with others out of hubs than save money at 250. Knock yourself out climbing out of Butte. I really wish we could give that place to Comair or ASA.

 

[VFR on Top]

The question then becomes do I pi$$ off center or do I fly the profile to keep the trip values high?

That's a rhetorical one, I hope....

 

[minrest]

It's so funny to see pilots who taxi on one engine to save fuel, and then climb at 290 in a tailwind, fly 4000 feet below max capable (because that's what filed) and fly .80 in cruise. Doesn't make any sense


Actually, it makes plenty of sense. You can't depart an airport below Release fuel. If you're taxiing out and not sure how long until you are released by ATC, common sense says to burn as little fuel as practical. Once you're assured of a release time, go ahead and start up the other engine. You may end up departing with a few hundred above release. If everything looks good to your destination after you're airborne, go ahead and push-up the speed a bit. In the Northeast corridor, you'll be a speed bump at M.74.

Also remember that your dispatcher has probably never even looked at your flight plan. They are computer generated. There's nothing wrong with deviating from the flight plan as long as you can be sure that you'll have sufficient fuel for the flight. It's called "Captain's Authority."

-minrest