May 16, 2018, © Leeham News: Pratt & Whitney has a long way to go to fix all its problems on the Geared Turbo Fan engine, but one airline customer says the situation is getting better.
Ted Christie, CFO of Spirit Airlines, said all five A320neos it’s received are now operating. These famously were pictured parked and months at the D/FW International Airport with covers on the engines.
The fuel burn is better than the advertised 15% reduction, Christie said, without specifying how much better. Industry scuttlebutt indicates the GTF is 1%-2% better than advertised.
Christie made his remarks yesterday at the 38th annual Airfinance Journal conference in Miami.
Things may be better, for Spirit at least, but another A320neo customer, lessor Air Lease Corp, says its A320neos deliveries are running about 11 months late. Steven Udvar-Hazy, the executive chairman, believes it will be 12-18 months before PW and other engine makers will “get back to normality.”
GE Aviation, CFM and Rolls-Royce each have engine challenges, Hazy said.
“The last 12 months has been a real eye-opener for engines,” Hazy said yesterday at the AFJ conference.
I wonder what the data says for an A320neo GTF versus an A320neo LEAP? Are they comparable, or does the GTF have a 3-5% advantage that had been talked about early on…
As the GTF-Powered A321neo/LR is getting better and better — leaving behind the 737-9/-10 — the harder it will be for Boeing to make the business case work for the MOM.
That makes zero sense.
As the GTF gets better and better the 797 gets better and better.
Its on an optimized wing vs the old A320 wing that is 31 years old.
Then add in the NEW GTF that is optimized for what the GTF can do that they had to be very conservative on in the first place.
And while the 3 engine mfgs are listed as equal, they are not. The RR Trent 1000 and to be seen Trent 10 (different engine but some core parts in common) are a real disaster and Boeing is not going to let that engine on a 797.
Pick a safe GE and the wave of the future and proven (other than nit noids) P&W GTF.
AFAIK, the current 35,000 lbs of (maximum) thrust PW1100G GTF engine is not powerful enough for the MOM. In short, the MOM requires an all new engine. Meanwhile, the A321neo/LR is cornering the 200 – 240 seat market segment. Come back in 2027.
Yes, I am a technician/mechanic/engineer, I have been around aircraft since age 2, I work on big stuff, I know it needs a new engine.
Yes I know and apparently you do not remember I fully acknowledged and agreed that the A321 is kicking Boeing butt.
Also note I never bought the 737-900/9 was a competitor, there is not Easter Bunny, Santa Clause or a tooth fairy (not to mention a twin engine A380) .
To spell it out.
1. There will be two engines offered on the 797
2. One will be the safe GE.
3. The other will be the engine mfg (P&W) who has proven they know how to do a GTF. P&W has been working on larger designs for the GTF for a long time.
There are two incompatible choices in there. Either a 2025-26 EIS or two engine choices. I doubt there is an engine OEM that wants to be the 2nd engine and enter service 12 mos after the first engine.
The business case for MOM partially depends on striking before Airbus has its production issues ironed out (A320Neo, A330Neo, A350, CS, and A400M–although some on that list are better off then others) so that Boeing can stack up the customer base/backlog before Airbus can deliver a credible response dividing the market back up to status quo of 50/50% (+-5%). Airbus obviously can walk and chew gum; but they can’t walk, chew gum, and finance a new launch with so many gliders waiting for engines because they aren’t getting paid. The 787-8 problems pushed the 787-9, -10, and 777X programs all to the right so Boeing knows how a production issue can upset product planning.
When at least 1/2 of Airbus’ problems lie with engine OEMs, one of which is a proposed 2nd engine supplier to the 797, I think there is a credible case for ignoring Udvar-Hazy on this one and going with one engine choice. Boeing can make U-H happy and add a 2nd engine when it does a major redesign.
“the current 35,000 lbs of (maximum) thrust PW1100G GTF engine is not powerful enough for the MOM.”
You do know that the new heavier 777X model has its engine with less power than its replacement ?
A lighter better optimised wing does wonders even for an aluminium fuselage.
Luckily Airbus can put a new carbon fibre wing developed quickly from its Cseries ‘cousin’ onto a new A321 type plane.
They could even add the tail section/empennage which is carbon fibre as well. All that means a 35,000lb thrust is OK.
And the end result is the ’31 year old A320 series’ has a new lease of life long before Boeings new plane/new engine
I think Airbus already propsed a stretch and rewinged A321++ to some key customers with 35k GTF’s, but then put it on hold, most likely the key customers (LH, AF, IAG) wanted more performance (new 37-40k engine). The 35k A320neo engines are not yet certified at that thrust level and they want to get the present LEAP-1A and PW1100G sorted out first before trying to reach the old 757 thrust of 37k.
LNR didnt think so
‘If so, launching the A322 sooner than later (and at a much lower cost will put Airbus in a position to capture the lower end of the MOM Sector.”
‘performance’ can mean many things, often it just means full loads out of short or hot/high airports or a bigger wing span that doesnt fit the standard gates.
But at the price point Boeing cant match and much sooner might suit the LCC and the majors who like a plane more like a 757 or 767 will just have to miss out
PW have said the GTF is scalable. GE have said the ceramic approach is reliable. My concern for the GTF is the planetary gears don’t have tapered bearings. I am expecting increasing vibration due to gyroscopic forces on the gear wheels wearing the flat bearings unevenly. With the ceramics in GE approach I ponder if too porous then salt and carbon could be a problem if too vitreous or hard degradation due to thermal expansion and cooling contraction..maybe the ceramic could be kept hot? Of the 2 I think gtf would be more relaible. Bring on a pw4000gtf for the747-8?
Transworld, the difference between the A321neo and the 797 is that the former can be purchased and flown on revenue flights, the latter is still vapourware. That gives Airbus sales now, profits, and plenty of time for an upgrade of their own.
I do feel sorry for Boeing’s engineers and designers. They’re perfectly capable of producing a fantastic aircraft, but the longer their management wait before committing to it the worse the business case for it becomes.
A321NEO available now? (well if you can get a couple of engine for it)
But who knew?
Kind of like telling me the sun rises someplace in the east isn’t it.
I never said anything to say otherwise have I.
Maybe less overstating the grossly obvious and contribute something worth while?
Vaporware refers to software, clearly Boeing has done a great deal of development on the 797.
They also did so on the Sonic cruisers. That did not come to be either, the 787 did.
You really need to understand aircraft development before throwing out terms that do not apply.
Is there any evidence you could link to as to what this magical 797 might be?
As far as I know it hasn’t been launched yet and very little data on it is in the public domain?
Until it is launched, designed, tested, and industrialised, I tend to agree with above opinion that it’s vapourware. A321neo can be ordered now, 797 can’t.
I think both the LEAP and PW1000 series have a design maximum of around 40k lbs for critical components. As could be expected, there is some growth potential left in the engines.
Boeing knows & probably calculates includes an A322 growth version in their longer term outlooks / business cases. It probably made the MoM / NMA grow a bit over the last 5 years.
Think AB wisely put the 321++ (322/3) on the back burner. The LEAP-A and GTF’s most likely max out at 35-37Klb, so enough for a 321+ with small stretch and new CAT-C wing, EIS 2 years before the 797?
AB could possibly be looking at an NMA/MoM (whatever you want to call it) based on an 50-60Klb Ultrafan ready for EIS in 10 years, 2 years or so behind the 797 but years ahead in engine technology.
The most probable engine for the 797 is a scale down GE9X, lika a “GE5X”. That will be “good enough”. The real danger is how good and mature the RR Ultrafan will be and if Boeing belives it will be on time, on cost and reliable, Still RR saved Boeing on the 757 when the PW2000 had its problems, so the young ones at Boeing most likely will go for the “GE5X” while the older ones think dual engine sources is a good insurance and good for competition. CFMI kept saying that the LEAP was “a CFM56 with 15% better SFC” but it was a brand new engine with its natural problems even though it is derived from the GEnX. The same people will probably claim “Derived from the proven GE9X, just a derivative from th GE90”. We will se who prevails at Boeing.
The only ones who have a say are the upper managers, probably the CEO.
And RR has a severely tarnished rep on the Boeing flagships aircraft.
RR is late to the game while P&W has real life experience with GTF and has been requested by parties unknown for a larger engine design/concept. Seal issue are miner nit noids, having the guts of your engine blow out is not.
We will see how the “new” PW1100G engines turn out to be. I guess thay incorporated close to 50 SB’s on the engines returned for the new airseal, so they might work pretty good. After next shop visit another 150 SB’s will be incoporated to take them to 35k thrust and make it the ovious choice for the A321neo.
The A321 ++ doesn’t really need a lot more power if it gets a new wider wing.
Early specifications show the PW1100 and LEAP are dimensioned up to 40k lbs.
777X has smaller thrust engines than the 777-200/300 current
If there is growth potential with the current PW1100 core, could we potentially see (for example) an 38Klb variant with say 85″ fan with higher by pass ratio?
If so, could open many possibilities for future developments of an 321 (+/+)?!
The core is the restriction. You can only push a core so much before you start loosing efficiency.
You can jack up the materials and run hotter, but that is not optimal in wringing out SFC.
I can see that a small stretch and empty mass increase can be compensated with new carbon wings and wingbox but Airbus put in on hold. There is a chance that key customer wanted much more payload-range hence driving up size of the wing and engine thrust with suitable engines not available in a timely manner. Udvar Hazy might some day tell what he wanted before sign the dotted line.
As commented somewhere else, an 47m A321 (“322”) with new wing and ~37/8 Klb engines with EIS around 2024(?) a reality. But, think AB realized airlines wants more and a twin aisle.
So won’t rule out an AB NMA/MoM, possibly pitched between the 797 and 787/(A330). Engines, 50-60Klb PW GTF’s and/or RR ultra fans, realistic EIS 2028?
We will see what the 797 turns out to be and if Airbus do the A322 with different MTOW classe. I would not be surprised if one option will be a pretty heavy 43k RR Ultrafan. (with the same core engine as on their 797 Ultrafan proposal.) With crude oil price passing $70/barrell and a required range of up to 5000nm you would thing fule burn is top prio. Weäll see what Boeing demands and what GE/CFMI can deliver or if it will be another race between RR and PWA with their geared fans.
I think Airbus will eventuall do the single aile A322 with a new carbon wing + wingbox and use RR ultrafan as one engine option forcing PWA or CFMI to upgrade thier engines. Most likley PWA only for a 37-42k engine to compete with a RR ultrafan. GE would most likely not upset Boeing with a 42k engine for Airbus using the 50-55k core 797 engine quenching Safran wiches for another derivative. MTU might take the lead with German money to develop this PW1142G engine in Munich, Ludwigsfelde and Hannover.
I don’t understand why anybody has any faith at all in RR’s Ultrafan. it took PW 20 years to get the gear system to the point where it had the required reliability/maintenance parameters for commercial service. what makes anybody think RR can deliver it in 10 when we are 15 years into T1000, which was a low tech derivative of earlier trents and it is still broken? even the re-design 1000-ten is just barely making fuel spec.
PW took a very conservative, proven approach to the core for the GTF, leaving lots of room for tech insertion and beat spec by ~2-3%, first PIP is said to give another 2%. They also said from day 1 that the existing GTF core was sized for 40k with minor tech insertion (improved 3D aero in the HP compressor, improved materials in the turbine, 85-90″ fan). if they can get over the turbines-101 type issues they have been facing (combustor liners and blade seals) then they should have a much easier ramp than RR.
Agreed fully. Most people are not mechanics (or engine designers) and don’t understand machinery and the learning curve.
I will add that I think the PIP II will be more like 3-5% better.
Your first go is ALL assumptions in your design path, you note the alternatives and pick the best one you think will work.
You build your first test set and find out you were wrong on a lot of it. If you are skilled and lucky, not much and you then can tweak.
You may find out you had flawed assumptions. You then make significant changes.
Those changes affect other things, you have to compensate for those changes as well.
In the end you build a pre production engine and test it.
Often there are more tweaks. Then you build production engine and like P&W, shortly find out there are some miner issue (if you are lucky they are miner)
Or like RR, you find it fails SFC but seems ok until the blades start to corrode and you replace all the blades and then you find you have a harmonic in the flow path (you knew there was an issue but went on anyway) and you have a basic core issue that has to be fixed.
And that is the shock, That sop stuff, it should never happen. RR had to drop the engine and start all over again it was so bad. Worst case scenario and the only analogues one was SNEMCA with their Silvercrest they tried to pull a tech rabbit out of the hat that was proven to be non viable and they failed.
P&W spent 20 years and billions figuring out the GTF. Not because it was non viable but because it had a whole new set of functionality that was different, even the small GTF did not show that.
RR is still on the learning curve and they have engineers scrambling to deal with the 1000 (possibly the TEN which does have 25% 1000 parts) and the Trent 900 + we have heard nothing about (an the 900 never even met the GP engine performance)
Thanks for your insightful commentary. It’s “minor” and “lose” though by the way. Peace.
RR seems to have no issues on Trent XWB. Some airlines have feed them back with lot of prises for the engine’s reliability and SFC. So, may be, RR will use this experience and make Ultrafan another fabulous engine.
@bilbo, with all respect, but I have to disagree. I have littel doubt that RR will make the Ultrafan a fabulous engine. But of course nobody knows when it will reach maturity and how well it will perform. But as we already see with the GTF, the fundamental progress of the geared fan is irresistible.
RR is not aiming for a MoM, but for large twins, this is meant to be a successor of the Trent engines. They sure know that conventional engines, including their 3-spool designs have reached their design limits. This is also one key reason for the problems they have currently – the further you drive performance, the less robust is any machine, no matter if it’s a computer chip or an aircraft engine.
Did P&W really work full throttle on the geard engine for 20 years? I don’t think so. I think for the longest time is was just simmering along and most probably small tasks were given to young engineers. On the other hand RR seems to invest quite heavily in this field, so I have little doubt that they will come forth with a usable product this decade.
As soon as that happens we’ll see a new round of NEOs. Certainly the A350, maybe also a modernized A380 with carbon wings too.
In service does not equate to “matches previous generation dispatch reliability rates.”
My guess is GE has a design, and bid submitted to Boeing, using GEnx, GE90 and LEAP tech on a new family. The issue is whether it is signature ready for Boeing with a timeline attached to that. This isn’t a new or secret project Boeing has sprung on any of the three makers, each of whom submitted different bids based on Boeing’s program parameters and different levels of exclusivity if I recall correctly.
What airline though, would hold off multiple years hoping the ultrafan is delivered and reliable for the first five years? Pffft.
P&W has been working on upscale GTF for some time. Airbus (possibly the A330NEO) or Boeing (possibly the NMA) requested a mid sized jet thrust engine at one point.
You can be sure that P&W knows what they would do if they are given the go. RR has given up on the Advance and gone to the Ultra (advance core is used) – not the same as having real world experience with the design and how to maximize what it can do.
The Pip II GTF for Airbus a few years is going to be another jump.
Can see AB launching the 320+ and 321+ with new wing with PW GTF Mark2’s, EIS 2 years or so ahead of the 797. Both ~3.5m stretches of the current models.
AB could retain the current 320 & 321 models as lower capacity and price option models. The new wing, landing gear and GTF+ could be used for an 321LR+ using the current 321 fuselage with increased MTOW and a couple of hundred NM increase in range?
PIP II is not a up-thrust , its a adjusting of the variable to improve efficiency.
I don’t know if they can also push it to 40k or that’s a new engine.
Airlines do not have the freakin slightest idea of how to measure engine efficiency per se during their operation.
When they say ‘15% better fuel burn’, what do they mean?
Is it for a given pair of cities, same amount of passengers and cargo carried from A to B, same cruise altitude, same cruise Mach number, block fuel measured over at least 20 flights? Is this how they get to their declared 15% better fuel burn?
There are Formulas derived in the 1950’s how to normalize Engine/aircraft performance and fuel burn to “standard day conditions”. So for a given trip inputting all the data and normalize you can see the fuel burn for a “standard day” and compare flights to flights hopefully getting a similar number even though your flights were at different temp/altitude/winds/fuel load/routes/pax and cargo loads. Most likely all Formulas are already inputted into some FMS’es.
Airlines also are know to operate dual Airbus and Boeing jets and when they fly the same routes they can do an apples to apples comparison.
That always been the interesting real world facts when Boeing claims they are better than Airbus and the real world ops say that they shift back and forth form one day to the next at 1% different.
Cleaner vs dirty airframe and engine, where the engine is at in its life cycle, atmospherics, additional maneuvering all play into that.
At 2% on a given engine, that’s a clear difference, but that is paper vs fact in the calculations vs what you found out.
In the real world though its major. People like that. It means you weren’t blowing smoke.
Both GE and RR under performed on the 787. RR was so bad they build a new engine. earliest NEO in history.
Boeing met SFC numbers as the airframe over performed just enough (even the -8)
That data long term on the A380 has been enough to show the GP does better than the RR.
That is important as RR with 3 Spool is more complex and cost more to overhaul. It has to do better, not even just break even to recover the costs vs the GP.
RR is in deep crap right now. Admittedly, I’m a GE (no pun intended) “Fan”, but I don’t see how anyone can objectively say that RR’s UltraFan will be this great, big, massive leap in technology and efficiency when they can’t even beat the GENx or GP7X on the A380, even when EA has basically not done a whole lot since they don’t see a big market for the A380 anymore, and RR still can’t beat them on efficiency (any wonder why EK is rumored to try to go EA again on future A380s, even when they went RR for a batch after RR promised too much?)
I think that P&W will get the GTF sorted, but I think that GE already has a GTF answer waiting and will counter P&W’s moves rather quickly. P&W is the one on the outs looking in for the 797, I think, as GE has to be in pole position to be the preferred engine choice, as their products right now are doing pretty well. (I’m betting a lot of RR Trent 1000 users are kicking themselves in the proverbial balls right now)
Looking back in history for the 757, GE designed a CF6-32 that was below expectations in SFC. Then GE closed the CF6-32 and teamed up with RR, they helped eatch other on the RB211-535 and CF6-80C2. That friendly RR relation with Brian Rowe as GEAE president lasted until RR did the wide cord fan blades on the RB211-524G for BA 747-400’s staying within agreed max fan diameter but making a CF6-80C2 competitor. The agreement was terminated over a weekend. Now you can have a similar situation where both RR and PWA come with geared fans and GE most liklely will bring a scale down GE9X. We will see what Boeins reactions are this time.
Commercial transport aircraft all have mass flowmeters on the engines that should provide fuel burn on a given flight to within 1% or so. Take a large enough sample set of flights and aircraft and you can hone in on fuel burn in given conditions with a high degree of confidence.
Trent 900: I know there are those of you who think I don’t know what I am talking about, and sometimes that is true.
But when it comes to tech stuff, I am well informed. Here is a direct quote from RR about the 900.
“At its annual results in March, Rolls-Royce estimated that the cash costs of fixing these and similar, but less extensive, problems affecting the Trent 900 on the A380 superjumbo would come to £750m in the three years to 2019.”
Not clear if its the old one or the new whiz bang one that was suddenly 5% better (BS per Tim, Clark of Emirates) than the GP.
Here is the link.
I can smell this stuff 3000 miles away. If they aren’t bragging (and Clarke nor RR are) then something has gone off the rails.
The Trent 900 also seems to be a fan blade issue but they are not talking about what aspect of the blades it is.
TW: I’m with you. I smelled RR’s BS on their sudden “our Trent 900 is 5% better” claim as soon as they said it. There was no way they could do that (about 7% efficiency gain overnight) and I’m thinking that’s why Tim Clark is going to be begging EA to give him something for any new A380 they decide to buy.
Yea that was my take at the time, the Trent 900 was 2% less SPC than the GP7000 an suddenly its 5% better??????????? Pile of Bull
And where there is BS there is a large Bull lurking.
TC is talking GP again and how they have agreed to “improve” the 7000.
Anyone can improve the numbers for a particular in of the OEMservice engine. Its not too hard as they are developing new technologies all the time. When a particular model goes into production, the overall design is frozen at it takes the technologies available.
5 years later newer tech comes on stream, some of it can be used in an older engine as a PIP, others require a new build version mostly for new airframes. Often the upgrades come at a price, depending on the volume that airlines may not wish to pay .
The people talking bullsh#t are those who think they really know something about aero engines when they are involved with construction diesels, which are literally agricultural engineering in comparison.
Ahh my fellow Leeham acquaintance, there you are wrong.
The tech changes but the basics stay the same. But if you are emotionally involved you have to TRY to insult someone to change the reality.
So, lets actually look at an ALL NEW engine, an RR no less with ALL the advantages plus new architecture (did not think I knew that one did you?).
So what did that get them. 5%, nope. 4%, seriously iffy. All of 3%!!!!!!!!!~ Whoppeee , new engine, new latest greatest techy. Pathetic is the word.
So you are going to claim that with a few fiddly bits that RR made the Trent 900 a never has been done joke of 7% better? Really?????.
We used to have an early Video game where when you hit the duck it burst into flames and did a screaming dive (dog barking in the background). Consider yourself shot down in flames.
As is said: Facts are true whether you believe them or not.
Your link is the FT which is $$ blocked. Its much better to have actual quotes rather than some ones elses summary which is further summarized.
What was RR actual statement and what engine was the 5% referring to. ?
Heres a specific example of what I was referring to:
‘A good example of such feedback arises from T1000’s elliptical leading-edge (ELE) high- and intermediate-pressure compressor (HPC and IPC) blades, which lower fuel burn and are available for all Trent models, including upgrade kits for the T800EP and T500EP+. The blades’ sophisticated aerodynamics, which reduces airflow separation behind the leading edge, provides a 0.5- to 0.7-percent benefit to fuel consumption worth up to $200,000 per aircraft per year, said R-R. With the higher benefit being felt by T800 operators, because that engine is older and therefore relatively less efficient, the first T800EP engine entered service last month.’
And more generally
‘Other developments, such as optimized blade-tip clearance, pocketless fan-spinner fairing, super-polished turbine hardware and HPC improvements, contributed to a 1.3-percent fuel-efficiency gain on new engines.’
I did not say they could not make miner improvements.
I said it will not be 5%
The 5% is a direct quote from TC (Trent 900 A380).
For an all new engine to get a few percentage improvement is pathetic.
And while you think a lowly mechanic does not understand metallurgy , we go.
Its not as sophisticated as a jet engine, but its there, and it has to perform and work.
I can go on endlessly about fasteners and their characteristics. I do metal stress relief and I do decision on grade of fasteners and the characteristics of those fasteners to do the job and do it right and why they are not.
And why if all the PR is right is RR having problems with those same blades? For them it should be like me getting to work on time in the morning, its routine.
Blades that corrode? Are you kidding me. That’s bolt grade 101.
And you could have man upped and apologized for the attempted insults.
Finding direct quotes myself doesnt come anywhere near ‘your 5%’
eg last year
“Previous engine improvements have lifted fuel performance by as much as 1.5 percent ‘with each package’, Schulz said Monday at the Paris Air Show. ”
Schulz was RR head of Civil aviation and they have had 2 EPs.
As usual you havent read the story fully and mixed up this proposed upgrade by Airbus.
“Airbus on Sunday announced plans to introduce a “plus” version of the A380 with aerodynamic changes, including the addition of winglets to improve fuel burn by 4 percent. ”
Aerodynamics arent RR territory!
Historically the engines Ametek fuel flow transmitters has not been that accurate and are replaced wth better ones in the test cells. When you refill after flight I guess you get a pretty accurate volume or mass upload.
What I know about aircraft engines are more than dangerous, but why not XWB’s for the A380?
Physical dimensions fairly similar to the T900, weight the big difference, 1T heavier than the T900 and 0.5T heavier than the GP7270.
Big question, will there be a market demand that warrants an NEO with say XWB’s, new wing lets, etc, certification cost, maybe even an A380-900? With oil prices rising there could be a return to the Hub-Hub principle.
Anton, none of the other Trent engines are really much better in their fundamental design than the 900 and that is the key reason the A380NEO hasn’t been launched yet.
My take is that Airbus is waiting for the Advance or the Ultrafan to mature. They will want to see some engines in the air before launching the NEO, and it looks we’ll have to wait a few years to see that happen.
I agree on that. Airbus feels that the A380 engines were ‘too early’ to catch the current ‘ engine standard technologies’ and they wouldnt want to be caught again doing that.
I would think GE would want to crank out a second gen Genx by 2025-6. (About 15 years out from 1st gen.) Why wouldn’t they work with this as their “base”, and downsize it to the 40,000 to 45,000 lb. thrust level—for the 797?
Sad news of an 737-200 going down shortly after take-off in Cuba with ~100 onboard.
Maybe RR and PW joining up again could work for a 50-60k lbs requirement. PW’s matured GTF technology and RR’s core / none bleed technology / WB foothold.
Get in MTU and you have a real powerhouse. An IAE 2.0 consortium. Might boost efficiency in the aftermarket too.
Too much bad blood between RR and PWA, also between RR and GE. Maybe MTU will buy PWA large Commercial Engines of 797 Engine size and up?
737 getting these geared turbo fans?