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Different Engines On The Same Type In A Fleet.  
User currently offlineTSL1011 From Canada, joined Jan 2004, 71 posts, RR: 0
Posted (8 years 11 months 3 weeks 5 days 23 hours ago) and read 4370 times:

Hi everyone.

I was sitting at work today and letting my mind wander (it can be the only exercise I get...) when I started thinking about airlines that have different powerplants on one type of plane within their fleet. The catalyst was seeing one of the 747-400s Cathay Pacific recently aquired from Singapore Airlines (specifically, B-HKD) here at YVR a few weeks back. These planes have PW powerplants, in a 744 fleet which is otherwise all RR powered. Other examples that come to mind are British Airway's B772s (RR and GE), Air Canada's B763s (PW and GE, I think) and American Airlines' B752s (RR and PW). (I know the second two examples are mixed fleets due to one airline taking over another's planes, but the first two were by choice, so to speak.)
My question is, do the pilots in these airlines have to be seperately rated to fly each engine/aircraft combination? Do the various powerplants cause significant differences, for example, in takeoff speeds and performance for a given weight or even different MTOWs? Or are they pretty much the same from the pilots perspective? In my first example, would Cathay have had to hire new pilots to fly the PW 747s, or at least spend time and money retraining some of their current pilots, or is there just one rating for the 747-400?
I know that different engines means more spare parts need to be stocked and more training is needed for the maintainance crews, meaning added costs. I'm kind of curious how much it adds to the aircrew costs as well.

Tim
CYVR

12 replies: All unread, jump to last
 
User currently offlineDougloid From , joined Dec 1969, posts, RR:
Reply 1, posted (8 years 11 months 3 weeks 5 days 14 hours ago) and read 4256 times:

Hmmmmmmmm.....good question.

The only thing I ever worked on that had a similar situation was on some Beech Kingairs that had Garrett engines on them instead of the more typical UACL PT6....although the pilot requirements were no different the way the aircraft performed was entirely different.....the kind of operating envelope that you can use when an engine offers you "instant-on" performance instead of having to set up for the wind up so to speak made it an entirely different and better aircraft. Plus you had all the bleed air you could ever want with no drop in performance....

With the big ones the key would be the maintenance and parts stocking issues on the one hand, and what the ultimate performance of each type of engine would be on the other....


User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 2, posted (8 years 11 months 3 weeks 5 days 14 hours ago) and read 4254 times:

I've never seen any intermix other than differing "dash numbers" which is not uncommon.
I've run a JT8-D-1 on one side and a -7 on the other, or a -7 and a -9 together. Usually it comes with operating limits on the more powerful engine.

Symmetrical intermix used to be common enough.

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With "two turning and two burning" as seen here. I see these all summer long. But the recips are symmetrical and the jets (which run on avgas) are symmetrical.



Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineZB330 From Netherlands, joined Aug 2005, 79 posts, RR: 0
Reply 3, posted (8 years 11 months 3 weeks 5 days 13 hours ago) and read 4247 times:

Doesn't add to flight crew training costs. In my airline we fly the A320 powered by CFM's and the A321 powered by IAE's. All pilots do a base check (simulator check) twice a year. Each base check consists out of two days. So one day we "fly" with CFM's and the other day we 'fly' with IAE's. It is just different sofeware which is loaded in to the sim.
And the only reason we do this is because the CFM's have a N1 indication which you normally use while the IAE's have a EPR indication.

ZB330

By the way you requested was about different engines on the same type within the fleet. Out of pilots point of view you can see the A320/A321 as more or less the same type.

[Edited 2005-09-27 16:54:10]

User currently offlinePihero From France, joined Jan 2005, 4445 posts, RR: 76
Reply 4, posted (8 years 11 months 3 weeks 5 days 6 hours ago) and read 4173 times:
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Quoting TSL1011 (Thread starter):
do the pilots in these airlines have to be seperately rated to fly each engine/aircraft combination?

Generally speaking, no.
Each pilot would be responsible for learning the differences from his flight manual.The first flight should be done with an instructor and that's about it.
In terms of performance, as each engine, for economical reasons has been closely taylored to the aircraft,it's quite transparent.
The worst I have personally seen was the mix of 747-100 cargo planes equipped with the venerable PW with a fleet of -200/300s powered by CF-6s. It was not fun going back to one's books to re-learn the operations of the JT-3 with water injection every three to six months. And I'm not even talking of the abominably poor performance of these PWs at max gross out of Mexico in the summer time !



Contrail designer
User currently offlineCALPilot From United States of America, joined Oct 1999, 998 posts, RR: 13
Reply 5, posted (8 years 11 months 3 weeks 5 days 6 hours ago) and read 4170 times:

UPS operates the B757 with mixed engines, P&W and RR's. You do not have different crews to fly the different sub-fleets.

Similar to operating different aircraft in the same sub-base, ie., the B767/B757 crew base at any of the airlines. It's no big deal.


User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 6, posted (8 years 11 months 3 weeks 5 days 5 hours ago) and read 4161 times:

Fedex has GE and P&W powered MD-11s. The P&W use EPR and start slower.

User currently offlineDougloid From , joined Dec 1969, posts, RR:
Reply 7, posted (8 years 11 months 3 weeks 4 days 15 hours ago) and read 4100 times:

Quoting Pihero (Reply 4):
It was not fun going back to one's books to re-learn the operations of the JT-3

JT3C/D were used on the B707 and 720 plus KC135.


User currently offlineLMP737 From , joined Dec 1969, posts, RR:
Reply 8, posted (8 years 11 months 3 weeks 4 days 13 hours ago) and read 4079 times:

Delta's 767's use both Pratt and GE motors.

User currently offlinePPVRA From Brazil, joined Nov 2004, 8964 posts, RR: 39
Reply 9, posted (8 years 11 months 3 weeks 4 days 12 hours ago) and read 4075 times:

Varig has GE and RR B777s, and their MD-11s are GE and PWs (I think). The MD-11s are especially a bad case since each aircraft has two different engines by default, so that's a total of 4 different engines/training/spare parts.

Cheers



"If goods do not cross borders, soldiers will" - Frederic Bastiat
User currently offlineJeffry747 From United States of America, joined Jun 2005, 963 posts, RR: 2
Reply 10, posted (8 years 11 months 3 weeks 4 days 9 hours ago) and read 4051 times:
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Quoting CALPilot (Reply 5):
UPS operates the B757 with mixed engines, P&W and RR's.

N401UP-N435UP- PW2000s.
N436UP-N475UP- RR RB211s.



C'mon Big B, FLY!
User currently offlineLitz From United States of America, joined Dec 2003, 1764 posts, RR: 0
Reply 11, posted (8 years 11 months 3 weeks 4 days 9 hours ago) and read 4048 times:
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Quoting LMP737 (Reply 8):
Delta's 767's use both Pratt and GE motors.

Which ones, on which planes (or models) ? Is there a list somewhere that shows this?

- litz


User currently offlineCloudy From , joined Dec 1969, posts, RR:
Reply 12, posted (8 years 11 months 3 weeks 1 day 1 hour ago) and read 3963 times:

Can anyone come up with examples that are not the result of a merger? The only thing I can think of is a few 777 operators may be forced to operate a mixed fleet for awhile because of the 777-300ER and 777-200LR use only GE engines.

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