Q400 Not A Slam Dunk

[CANCELIFR]

Hey Rudder, whose loads to LGA are appalling?

[internet]

0 would be "appalling" which is what the loads are until June 4th.

[rudder]

There is a reason that AC's most cancelled city pair is YYZ-LGA. And AC operates mostly with sub-100 seat gauge aircraft on the route. Operationally, dedicating aircraft to LGA as a destination is an operational nightmare and a waste of an otherwise valuable asset. I would expect that WJ will have to start the route with 737's to preserve the slots but that a switch to Q400's would not be unreasonable.

[Bobcaygeon]

The Q400 fuel economics margin narrows significantly if you run it at ATRish speeds. You can slow a Q400 but you can't make an ATR 72 go fast.

With satellite communications now you can monitor operations and ACARS the crew when they aren't operating at the flight planned cruise speeds. ie going fast cause they want to get home early.

[rudder]

How slow (KTAS) can you run a Q400 and what is the % fuel consumption reduction compared to max cruise TAS?

Found speed info here:

http://press.commercialaircraft.bombardier.com/pdf/Q400_brochure_en.pdf

[internet]

There is a reason that AC's most cancelled city pair is YYZ-LGA. And AC operates mostly with sub-100 seat gauge aircraft on the route. Operationally, dedicating aircraft to LGA as a destination is an operational nightmare and a waste of an otherwise valuable asset. I would expect that WJ will have to start the route with 737's to preserve the slots but that a switch to Q400's would not be unreasonable.

Same-day return on Monday is $1220.28 on AC. I can assure you, that when WJ arrives, the walk up fare will be less than half that. We've been through this too many times to count, low fares stimulate demand. Is the -600 too big? Maybe at certain times of the day.

[rudder]

Cheaper fares won't get you in and out of LGA any faster on a bad day

[internet]

Cheaper fares won't get you in and out of LGA any faster on a bad day

You're right. But if AC and WJ are both going to sit there, I'd rather have WJ's cost structure than AC's.

[Thebean]

How slow (KTAS) can you run a Q400 and what is the % fuel consumption reduction compared to max cruise TAS?

I can get my sports car's gas mileage to dramatically improve if I don't drive the crap out of it.

Unfortunately, no matter how economically I drive it, it's alway consumes about 20% more fuel than Mrs Bean's Miata. The engine and overall weight conspire against my miserly desires.

No matter how slow I drive it, it still costs me 25% more to ship the sports car to Hawaii because of its added weight.

[Fido]

What did you find when researching engine overhaul costs on the Q400 vs ATR?

When all costs are taken into account the difference between an ATR and a Q400 is neglible.

From the cost side it becomes which manufaturer gives the biggest discount on price.

From the revenue side the Q400 wins by a decent margin

From the opoerational side the Q400 wins again

In the end though, if the ATR comes down even more in price, take it.

[DEFCON]

Does anyone have the data comparing the fuel burns of the Q4 @ an lrc of 287kts to the ATR 72-6 @ a 276 kt hsc? Also; when the Q4 operates at the lower power, by how much are the associated engine mtx costs reduced and by comparison; what are the associated ATR engine costs if operated at max cruise power settings?

[rudder]

Toughest phase of flight for a turbine engine is idle thrust to T/O thrust (rapid temp rise and peak temp). Once air is flowing through the engine, temp stabilises at a lower level. Hence the value of derated thrust for T/O. I doubt that reduced cruise power setting would extend engine life but the value would be based on reduced fuel flow and the resulting specific range metric (lbs/nm).

[DEFCON]

Reduced demand on an engine surely would extend its life. Maybe things have changed, but I was always under the impression most engine failures occured with the first after T/O power reduction due to the rapid temp / pressure change. The reduced thrust T/O profiles everyone’s familiar with today are apparently employed for this reason?

[boestar]

Defcon:

you don't get credit for taking it easy but you are penalized for overtaxing.

you can run the engine at very low poer settings but The TBO is the TBO. If you have an engine failure after V1 and need the extra power from the good engine then there is a calculation to be done that reduces that TBO. I am not sure what the hit is on the Q400.

[DEFCON]

If there's a calculation done to reduce the TBO because you needed 'full' power on a particular T/O; then you are in fact gaining 'credit for taking it easy' by virtue of the now normal 'reduced thrust' T/O's?

In the same vein; I looked at the Q4 data Rudder posted earlier and noticed, the LRC power settings are a 'special approval' item. Correct me if I'm wrong, but that ‘often’ means someone's paid for the privilege, done the work and now 'owns’; the STC. Operators etc go through or pay for the approval because they can then employ an 'approved' procedure that results in an economic benefit / advantage. I presumed there’d be a mtx advantage in addition to fuel savings realized in the present case and that’s why I asked the question regarding comparative savings.

.

[SkyBlazer]

all I have to say is - single engine service ceiling !

The ATR is 11000 ft - thats going to put alot of those mountains up close.

Q400 is a better aircraft hands down - RNP certification, CAT 3 capable.... The list goes on.

SB

[boestar]

Defcon:

You can't really call it a credit. If the engine is delivered with a 2000Hr TBO (it is WAY higher than the BTW) and you use the regular full power takeoffs etc. then you pull the engine at 2000Hr. However if you have an engine out the there is some spare power available on the other side (some call it APR among other names) when this "reserve" is used it uses time at a faster rate for example 1.2:1. This effectively reduces the TBO by a specified amount.

Of course this TBO only applies to the life limited parts on the engine, many parts are on condition and no specific "life" is given.

[Mitch Cronin]

Interesting look into the world of LRT's Boestar... BRT's are not like that... their components are staggered in TX dates, and their excursions to max T/O power are not limited. Only exceedences of temp, vib, or RPM (or ugly findings during inspection) have consequences for time limits.

[Bobcaygeon]

If there's a calculation done to reduce the TBO because you needed 'full' power on a particular T/O; then you are in fact gaining 'credit for taking it easy' by virtue of the now normal 'reduced thrust' T/O's?

In the same vein; I looked at the Q4 data Rudder posted earlier and noticed, the LRC power settings are a 'special approval' item. Correct me if I'm wrong, but that ‘often’ means someone's paid for the privilege, done the work and now 'owns’; the STC. Operators etc go through or pay for the approval because they can then employ an 'approved' procedure that results in an economic benefit / advantage. I presumed there’d be a mtx advantage in addition to fuel savings realized in the present case and that’s why I asked the question regarding comparative savings.

.

Defcon, as a former Dash 8 you pilot should be aware that Bombardier charges for everything possible ie contaminated runway supplement, narrow runway supplement, it's Tuesday supplement, etc).

Reduced power may not extend TBO's but most PW turbo prop engines get increased TBO's based on "on-condition" extensions based on operator history with that engine and overhaul/hot section results.

Not working the PW150 on the Q400 should likely lower hot section & overhaul costs relative to the hard working PW 127M engine on the ATR 72-600

Note: Slightly related, the purchase costs of a PT6-67 vs PT6-65 are large but the hot section and overhaul costs more than make up the difference quickly due to the design limit margins (-67 could easily produce more power, -65 is stretched to it's max.)

[DEFCON]

Bobcaygeon

I understand you to mean; TBO is an 'out of the box' certification stipulation, but the operator can expect to gain progressive extensions to the original TBO based on his experience etc. At this point the TBO stipulation becomes something of a historic starting point making the operator the beneficiary of all that comes with an approved 'on condition' mtx program. Further; reducing the 'in service' demand on an engine will result in lower engine mtx costs.

If the above interpretation is accurate, I believe we've been in agreement?

.

[boestar]

Defcon:

TBO os a life limit determination by the manufacturer of the component. In the case of the engine ALL of the rotating parts have a life which cannot be extended EVER. Experience does not play a roll in it. It was determined that the stresses induced during operation will provide for X number of hours after which the part is scrap. If, however, certain margins are exceeded in operation that TBO or LIFE will be reduced by a specified amount. Now on certain inspection criteria having a proper program of inspection in place and gathering coroborating data, the inspection can be excalated to a longer interval to save some coin. That data takes time to gather. For a new operator it can take a long time indeed.

[DEFCON]

Boestar

We're on the same page then?