united319 From United States of America, joined Jul 2006, 549 posts, RR: 0 Posted (1 year 7 months 3 weeks 9 hours ago) and read 6039 times:
Just noticed in the new photos that AA has different engines on their A319 & A321 fleets....
The A319 has CFM's and the A321 has IAE V2500's...doesn't seem to make sense for brand new aircraft. I would think they would want the same engine manufacturer on their aircraft. Can anyone shed light on this?
Starlionblue From Greenland, joined Feb 2004, 17327 posts, RR: 66
Reply 1, posted (1 year 7 months 3 weeks 9 hours ago) and read 6034 times:
Quoting united319 (Thread starter): The A319 has CFM's and the A321 has IAE V2500's...doesn't seem to make sense for brand new aircraft. I would think they would want the same engine manufacturer on their aircraft. Can anyone shed light on this?
I'm thinking it makes sense.
- The two aircraft have very different weights and somewhat different missions, so methinks different engines might be optimal.
- Given the size of AA's fleet, arguments about economies of scale and commonality between models weaken somewhat. Sure, if you have 5x A319 + 8x A321 in total, commonality is a big thing. AA wil have 65x A319 + 65x A321. Quite enough to realize any economies of scale within one model.
- Having two manufacturers ensures competition.
- Given the volumes involved, delivery slots come into play. Perhaps one manufacturer couldn't provide all the desired engines in the desired timeframe.
"There are no stupid questions, but there are a lot of inquisitive idiots."
SPREE34 From United States of America, joined Jun 2004, 2341 posts, RR: 8
Reply 2, posted (1 year 7 months 3 weeks 8 hours ago) and read 6016 times:
The CFM is better suited to shorter legs. The IAE is the better performer on longer legs, and and offers a higher thrust rating, so is the better engine for the 321. I believe Lufthansa if following the same logic. US Airways did as well after the merge with America West.
I don't understand everything I don't know about this.
BlueJuice From United States of America, joined Jun 2010, 281 posts, RR: 0
Reply 6, posted (1 year 7 months 2 weeks 5 days 19 hours ago) and read 5271 times:
Does "Power by the Hour" also play into the equation? I am guessing when fuel was cheap and airlines were responsible for all engine ownership/maintenance/spare parts, the loss in efficiency was made up with a simpler technical operations. Nowadays it seems airlines want to squeeze out every fraction of a percent in operating efficiency. Having the manufacturer bear the cost of engines and maintenance means the airlines can lease the exact engine needed for a particular mission. Am I making a correct assumption?
Could be, not sure how their contracts are set up here. The architecture of the two engines largely determines their optimality, the V2500 has two HPT stages while the CFM56 has one. This means lower mx costs for CFM, but better SFC for V2500. MX on HPT is largely a function of cycles (heating/cooling stress), whereas SFC benefit is a function of distance flown and becomes more important on longer sectors. Thus, the short runs favor CFM because there are fewer expensive parts to replace regularly, while longer sectors favor IAE because you have relatively more hours/cycle, which shifts the equation more to burn and away from mx.
roseflyer From United States of America, joined Feb 2004, 10390 posts, RR: 52
Reply 8, posted (1 year 7 months 2 weeks 5 days 14 hours ago) and read 5181 times:
Quoting BlueJuice (Reply 6): Does "Power by the Hour" also play into the equation?
That was my first thought. I suspect AA might be doing power by the hour. When your engine is power by the hour, you depend on the engine manufacturer for all your support. There's very little benefit to engine commonality because AA won't be doing much engine work in house. The only engine work that they'd be doing is the type that doesn't vary much depending on engine type.
If you have never designed an airplane part before, let the real designers do the work!
The A319 comes available with the V2527M-A5 engines which produce 27k pounds of thrust, so that isn't an issues. The A319s will be used or short to medium stage lengths which are better suited for the CFM56-5B7 due to lower maintenance costs associated with the short haul environment wear and tear.