Indigo set an altitude limit of 30,000 ft for the A320NEO fleet

AirbusMDCFAN · Sat Mar 25, 2017 9:28 pm

Link/Source: http://jetlinemarvel.net/2017/03/25/ind ... ne-strain/

Indigo has sent a max altitude cap of 30,000 feet for it's A320NEO fleet, to help reduce strain on the P&W engines.

How much more fuel will the P&W1100GTF NEO engines burn at 30,000 vs if the aircraft were to go to 36,000 - 39,000 feet.

KFLLCFII · Sat Mar 25, 2017 10:19 pm

I've been out of flying for a long time now, but wouldn't a lower altitude limit actually force the engines to work harder? (Denser air = more fuel burn/hotter, while longer flights = more total burn time?)

Newbiepilot · Sat Mar 25, 2017 11:25 pm

I find this interesting. Is this a new problem with the engine:

"On 21 March, Ashim Mittra, vice-president (flight operations), IndiGo, said in a note to pilots that Pratt & Whitney had proposed limiting the altitude of flying to 30,000 feet for A320neo planes to avoid a possible glitch in the engine lubrication system and that, effective 22 March, IndiGo had decided to adopt the recommendation. Mint has seen a copy of the note. Since flying at lower altitudes consumes more fuel, the note asked pilots to fuel up accordingly."

lightsaber · Sat Mar 25, 2017 11:44 pm

Lower altitude also reduces the peak temperature during climb. The NEO combustor are having durability issues and a lower initial climb helps. But step climbing would mitigate if always flying below maximum possible cruise. This sounds like solving two issues with one easy to understand set of rules.

Fuel burn doesn't effect combustor durability. It is peak temperature. Ironically, flying lower will run the combustor and turbine inlet guide vanes colder as it avoids an end of climb trap where the pressure drop across the combustor is reduced increasing temperature due to reduced cooling effectiveness.

Lightsaber

Newbiepilot · Sat Mar 25, 2017 11:49 pm

Is the combustor problem the same lubrication problem that the article is referencing? If PW is recommending altitude limits, that is a big step.

anshabhi · Sun Mar 26, 2017 1:56 am

This brings 6E's brand new NEOs and AI's 25 year old CEOs on level!

prebennorholm · Sun Mar 26, 2017 1:58 am

KFLLCFII wrote:
I've been out of flying for a long time now, but wouldn't a lower altitude limit actually force the engines to work harder? (Denser air = more fuel burn/hotter, while longer flights = more total burn time?)

Nah, it is basically correct what they tell in the link.

Cruising at FL300 and FL360 will demand almost identical thrust since the lift/drag ratio of the plane at economic speed will be almost identical. But to produce the same thrust in the less dense air at FL360 the engine will have to spin faster. There will be less air mass to pass the core, so it will have to burn hotter. Less cooling air will be available. The exhaust gas temperature will be higher.

But economic speed at FL300 is slower than at FL360, so fuel burn will go up slightly.

The main issue is maybe to totally avoid the extra strain on the engines during climb from FL300 to FL360. It is likely that the procedure change also involves a less steep climb to FL300.

aemoreira1981 · Sun Mar 26, 2017 2:56 am

All of a sudden, Qatar Airways' decision to cancel its A320 orders (it had selected the Pratt & Whitney engine) seems prudent. I will expect that most orders will prefer the LEAP engine going forward, which I have not really heard of as having problems.

As for Air India's A320s---some of them are 28 years old (with double-digit line numbers).

Channex757 · Sun Mar 26, 2017 5:55 am

aemoreira1981 wrote:
All of a sudden, Qatar Airways' decision to cancel its A320 orders (it had selected the Pratt & Whitney engine) seems prudent. I will expect that most orders will prefer the LEAP engine going forward, which I have not really heard of as having problems.

As for Air India's A320s---some of them are 28 years old (with double-digit line numbers).

That isn't the way the industry works.

An example is the problems BA had with a new engine variety for which it was the launch customer. They worked with the manufacturer until they got it right. The GE90 went on to be hugely reliable and sell plenty.

Same went with the early JT9D on the 747-100. That was a dog of an engine. Airlines didn't have much choice at that stage but again it came right in the end. It isn't the probems or issues early on that have a bearing on sales, it's how that engine is going to perform over its lifetime as well as the credibility of the vendor to get it right fast. Penalties come into play as well. The GTF engine holds so much promise I doubt sales will be affected too much. That's what came into play with the two examples I give above. Pratt and Whitney have been in the game long enough to have developed credibility so this should help carry the engine forward.

PlanesNTrains · Sun Mar 26, 2017 6:08 am

aemoreira1981 wrote:
All of a sudden, Qatar Airways' decision to cancel its A320 orders (it had selected the Pratt & Whitney engine) seems prudent. I will expect that most orders will prefer the LEAP engine going forward, which I have not really heard of as having problems.

As for Air India's A320s---some of them are 28 years old (with double-digit line numbers).

Well, they were deferred and not canceled, per se, but I'm not clear if this is just a temporary measure until a fix is in place? As far as the order breakdown, I thought there was a hard limit for each engine on the A32Xneo where a maximum ratio was allowed - is that accurate or based in reality?

tb727 · Sun Mar 26, 2017 12:50 pm

Everyone that is operating the PW engine is doing this or will be soon. Honestly with the fuel burn it doesn't matter a lot with that airplane, there isn't much of a difference in the upper 30's to the lower 30's and can be a dog at high altitudes. Only problem is it's coming up on summer and nothing like dodging weather down low. It's not a hard limit so if you have to climb above it to avoid it, make it so.

cat3appr50 · Sun Mar 26, 2017 8:58 pm

Assuming an estimated 1000-1500 NM avg. flight with the same flight route and winds and temperatures aloft, looks like an A320Neo at FL 360-380 will surely burn less fuel than at FL300. It would be challenging to pilot a commercial (jet) aircraft limited to a ceiling of FL300 relative to potential weather conditions encountered, etc. and the resulting contingency limits. With the diverse weather we get in the USA anyway, that would be quite challenging to say the least, including financially challenging.

Don’t know how long that limit is expected to be in force at Indigo due to whatever engine problem there may be, but if it goes on a long time and with around 150 aircraft of that type (assuming of course they’re all under that ceiling restriction), it would seem prudent to be looking at some capital costs versus operating costs financial cases.

Just my personal opinion.

448205 · Sun Mar 26, 2017 9:26 pm

NK has been doing this for more than a month.

adolecentslookingatpicturesofairliners.net strikes again.

Newbiepilot · Sun Mar 26, 2017 9:26 pm

cat3appr50 wrote:
Assuming an estimated 1000-1500 NM avg. flight with the same flight route and winds and temperatures aloft, looks like an A320Neo at FL 360-380 will surely burn less fuel than at FL300. It would be challenging to pilot a commercial (jet) aircraft limited to a ceiling of FL300 relative to potential weather conditions encountered, etc. and the resulting contingency limits. With the diverse weather we get in the USA anyway, that would be quite challenging to say the least, including financially challenging.

Don’t know how long that limit is expected to be in force at Indigo due to whatever engine problem there may be, but if it goes on a long time and with around 150 aircraft of that type (assuming of course they’re all under that ceiling restriction), it would seem prudent to be looking at some capital costs versus operating costs financial cases.

Just my personal opinion.

I can picture some heated conversations between IndiGo, Airbus and Pratt executives with IndiGo demanding compensation and free of charge fixes and Service Bulletins. The Indian Regulatory Authorities may be involved too:
https://thewire.in/112880/dgca-aviation ... a320-neos/

Does anyone know if a 30K altitude restriction will impact dispatch clearances other than weather deviations? I don't know how crowded airspace is in India, but if they are filing for lower altitudes, may they have sequencing trouble or less direct routing?

Woodreau · Mon Mar 27, 2017 1:22 am

It is not a restriction. It's just recommended that the PW engines stay at FL300 or below as much as practicable. Pilots may climb up to the max certified altitude of FL398 if deemed necessary by the pilot.

By planning the flight at FL300 you are already carrying the extra fuel needed. If you climb above FL300 you have more fuel than you need for the flight.

BawliBooch · Mon Mar 27, 2017 1:54 am

aemoreira1981 wrote:
As for Air India's A320s---some of them are 28 years old (with double-digit line numbers).

14 (ex-IC) out of 60+ A32S's in Air India's fleet are 24+ years old - these are the ones powered by V2500 engines. The rest are of newer vintage powered by CFM56 engines. The 2 latest A320NEO's are LEAP1A powered.

IC was one of the first airlines worldwide to introduce the V2500 powered A320's and they had major problems with them on induction. For a year or so following induction in 1989 with higher fuel burn than promised and various maintenance "bugs". If it matters they were also restricted to 28000 feet for quite some time. Lot of bad blood followed when IC sued. When AI bought 14 of these mothballed A320's back into service in 2012, they were also restricted to below FL280 for some reason.

Air India's old A320 v1's operating under restrictions?

Newbiepilot · Mon Mar 27, 2017 10:49 am

Woodreau wrote:
It is not a restriction. It's just recommended that the PW engines stay at FL300 or below as much as practicable. Pilots may climb up to the max certified altitude of FL398 if deemed necessary by the pilot.

By planning the flight at FL300 you are already carrying the extra fuel needed. If you climb above FL300 you have more fuel than you need for the flight.

Is it being communicated as a flight crew operations manual bulletin or is this just a limit on the cruising altitude issued on flight plans? Sounds a lot easier to deal with than ice crystal icing restrictions were on the GEnx.

Woodreau · Mon Mar 27, 2017 1:45 pm

There was an operating bulletin published regarding this issue. (No different than any other issue I suppose, like the operating bulletin for erroneous date/time indication on the aircraft clock that may occur only in the month of February 2017)

Dispatch will plan NEO flights no higher than FL300 and give you the fuel to operate the flight safely at FL300.
Pilots are free to operate the aircraft up to its max certified altitude.

gloom · Mon Mar 27, 2017 2:22 pm

For A320 CEO, estimated FF from BADA files on F300 is 45.1kg/min, F360 goves 40kg/min. Numbers are for nominal conditions, specified at 62t weight and ISA.
Based on that, I'd expect more-or-less 10% penalty over long range, and bit less than that on short hops. Of course, this is just estimation.

Cheers,
Adam

JoeCanuck · Mon Mar 27, 2017 7:11 pm

gloom wrote:
For A320 CEO, estimated FF from BADA files on F300 is 45.1kg/min, F360 goves 40kg/min. Numbers are for nominal conditions, specified at 62t weight and ISA.
Based on that, I'd expect more-or-less 10% penalty over long range, and bit less than that on short hops. Of course, this is just estimation.

Cheers,
Adam

So a ceo at 36,000ft, has close to the same fuel burn as a neo at 30,000ft.

Here's something I'm saying way too often; "I'm a huge fan of Pratt and the GTF, but it kind of seems like they're dropping the ball.".

Right now, they have a huge lead with their gearbox...but they've been working on it for decades and they seem to have that part figured out. It seems they may have neglected a lot of other rather important stuff on the way...and the competition isn't exactly sitting idly by. Both GE and RR are working on their own GTF's...and GE especially seems to be doing all of the other stuff right, to the point where adding a gear box to the fan might be a fairly simple deal. They already have gearboxes on some very powerful helicopter engines.

I don't think it's out of the realms of possibility that we'll see a GTF on a LEAP engine a few years down the road.
It's about time we heard some good news from the Pratt camp.

Pie11e · Wed Apr 05, 2017 10:21 am

Any idea on how long this limitation will last ?

That's at least 1,000 $ additional cost per aircraft per day for the GTF engine due to the non-optimized altitude !!!

KarelXWB · Wed Apr 05, 2017 10:24 am

Pie11e wrote:
Any idea on how long this limitation will last ?

A new bearing seal will be introduced later this month.

Pie11e · Tue Jun 13, 2017 10:21 am

"P&W reports that its carbon seal improvement package received certification on 12 April and is deployed to all its operators. The company tells Low Cost & Regional Airline Business that all customers have completed the No 3 upgrade." (in http://www.lowcostandregional.com/featu ... gine-snags)

That's good news indeed!

But it seems that Indian operators are still stuck at FL300... (e.g. https://www.flightradar24.com/data/aircraft/vt-itc)

KarelXWB · Tue Jun 13, 2017 10:25 am

Pie11e wrote:
But it seems that Indian operators are still stuck at FL300... (e.g. https://www.flightradar24.com/data/aircraft/vt-itc)

The DGCA is still going through the paper work.

Pie11e · Wed Jun 14, 2017 6:40 am

KarelXWB wrote:
Pie11e wrote:
But it seems that Indian operators are still stuck at FL300... (e.g. https://www.flightradar24.com/data/aircraft/vt-itc)

The DGCA is still going through the paper work.

So Spirit must be waiting also for the same reason before going back to normal cruise FL ...

dtw2hyd · Wed Jun 14, 2017 11:38 am

A news report suggests DGCA still waiting on PW for an update.

http://www.moneycontrol.com/news/trends ... 01193.html

With private carriers involved and possibly enough palms greased, PW shouldn't expect to get off easily, even though they are doing an excellent job supporting their customers.

Newbiepilot · Tue Jul 11, 2017 2:10 pm

Im not sure why, but a moderator locked a thread that had a rumor that IndiGo has 8 A320neos are currently grounded. Does anyone have information on that?

viewtopic.php?f=3&t=1368011

whiplash · Tue Jul 11, 2017 2:31 pm

Newbiepilot wrote:
Im not sure why, but a moderator locked a thread that had a rumor that IndiGo has 8 A320neos are currently grounded. Does anyone have information on that?

viewtopic.php?f=3&t=1368011

Thanks for replying here. I am really curious as to how its possible for 8 Indigo aircrafts to be standing on ground, and a lot of noise not being made. A friend of mine is an FO with Indigo and claims that Indigo has a sweet deal with P&W, where the former pays for any revenue loss because of their engines. How true is this?

anshabhi · Tue Jul 11, 2017 2:40 pm

I am SHOCKED

VT-ITF,G,H,J,K,M,N,O are parked.

AeroTyke · Tue Jul 11, 2017 2:48 pm

anshabhi wrote:
I am SHOCKED

VT-ITF,G,H,J,K,M,N,O are parked.

VT-ITH is in service. VT-ITS is parked.

Newbiepilot · Tue Jul 11, 2017 3:10 pm

whiplash wrote:
Newbiepilot wrote:
Im not sure why, but a moderator locked a thread that had a rumor that IndiGo has 8 A320neos are currently grounded. Does anyone have information on that?

viewtopic.php?f=3&t=1368011

Thanks for replying here. I am really curious as to how its possible for 8 Indigo aircrafts to be standing on ground, and a lot of noise not being made. A friend of mine is an FO with Indigo and claims that Indigo has a sweet deal with P&W, where the former pays for any revenue loss because of their engines. How true is this?

There has been noise about problems, but the discussion of A320neos that are actually grounded has been limited. I don't think the airlines or manufacturers want to discuss how many planes are actually grounded because of the engine problems. Without hard links and hard news, moderators might lock threads about rumors.

I would expect warranty to pay for repairs but loss of revenue is rarely included in warranty contracts.

dtw2hyd · Tue Jul 11, 2017 3:12 pm

Must be really really short on spares, otherwise, vendors wouldn't keep these on the ground and pay hefty compensation to 6E.

Or 6E burned up DGCA allowed cycles/hours.

anshabhi · Tue Jul 11, 2017 3:18 pm

dtw2hyd wrote:
Must be really really short on spares, otherwise, vendors wouldn't keep these on the ground and pay hefty compensation to 6E.

Or 6E burned up DGCA allowed cycles/hours.

They recently took delivery of a 13 year old CEO!! I don't get this...

dtw2hyd · Tue Jul 11, 2017 3:19 pm

anshabhi wrote:
dtw2hyd wrote:
Must be really really short on spares, otherwise, vendors wouldn't keep these on the ground and pay hefty compensation to 6E.

Or 6E burned up DGCA allowed cycles/hours.

They recently took delivery of a 13 year old CEO!! I don't get this...

They will scoop up any free A320CEO until NEOs are issue free. Kind of deviation from their premium support model, because getting premium support on a 13-year-old frame would cost an arm and a leg. May be they will sign a support contract with AIESL.

Okie · Tue Jul 11, 2017 3:27 pm

One of the 320neo birds was grounded at Patna on June 30 until July 5 waiting on engine due to turbine failure on take off.

I have no idea which frame.

Okie

whiplash · Tue Jul 11, 2017 3:30 pm

anshabhi wrote:
I am SHOCKED

VT-ITF,G,H,J,K,M,N,O are parked.

How did you find out the tail numbers?

anshabhi · Tue Jul 11, 2017 3:48 pm

whiplash wrote:
anshabhi wrote:
I am SHOCKED

VT-ITF,G,H,J,K,M,N,O are parked.

How did you find out the tail numbers?

FR24.

Okie wrote:
One of the 320neo birds was grounded at Patna on June 30 until July 5 waiting on engine due to turbine failure on take off.

I have no idea which frame.

It wasn't a NEO. VT-IFC

ameya wrote:
..

please provide some details on this!!

anshabhi · Tue Jul 11, 2017 4:40 pm

could it be that these are the actual NEOs which are supposed to replace the CEOs which 6E leased in while the neo were being delayed?

If the aircraft are perfect and enough demand is not there for 6E to deploy them, why would it take them? A320neo is in extremely high demand..

Are there any such known issues with any other airline?

dc10lover · Tue Jul 11, 2017 4:47 pm

So much for "Pure Power".

Polot · Tue Jul 11, 2017 4:49 pm

anshabhi wrote:
If the aircraft are perfect and enough demand is not there for 6E to deploy them, why would it take them? A320neo is in extremely high demand..

Because they are obviously not perfect, something is wrong with their engines so they are parked for the time being. 6E is not going to take delivery of brand new aircraft and just park them because they don't need them yet. That would be an incredibly worrying sign, considering 6E has committed to over 400 Neos (+50 ATRs) vs a fleet of ~100 Ceos. They should be ready to handle rapid growth.

dynkrisolo · Tue Jul 11, 2017 6:50 pm

I'm surprised this is not reported by anyone. I went to FR24 and see if there are other PW1100G A320neos grounded. Here's what I have found.

Volaris newly deliverd N529VL has yet to enter service, this one doesn't count.

As previously stated, IndiGo's VT-ITF, G, J, K,M, N, O and S are grounded, out of a total fleet of 22.

Spirit still has two out of five (N901NK and N905NK) grounded.

LATAM Brazil has one out of two (PT-TMN) grounded.

Hong Kong Express has one out of three (B-LCL) grounded.

China Southern two out of seven (B-8673 and B-8637) grounded.

Both of ANA's two neos have not been flown since July 8th (JA211A & JA212A).

So, 16 out of the 55 PW-powered neos delivered (not including the Volaris second aircraft) are out of service.

musapapaya · Tue Jul 11, 2017 7:39 pm

Those 5 (D-AINA - D-AINE) A320NEO with Lufthansa seems to be happily flying!

N212R · Tue Jul 11, 2017 8:34 pm

musapapaya wrote:
Those 5 (D-AINA - D-AINE) A320NEO with Lufthansa seems to be happily flying!

Flying yes, how happy they're making their owners and operators is a different question.

hOMSaR · Wed Jul 12, 2017 1:43 am

What constitutes "grounded" in this sense? If we're using FR24 (or other public website, vs some internal maintenance system), how long does a plane have to be on the ground before we say it's grounded?

anshabhi · Wed Jul 12, 2017 2:49 am

hOMSaR wrote:
What constitutes "grounded" in this sense? If we're using FR24 (or other public website, vs some internal maintenance system), how long does a plane have to be on the ground before we say it's grounded?

Even a week is enough to conclude that a plane is grounded, IMO.

TOI has an article on it today:

http://timesofindia.indiatimes.com/indi ... n=referral

They are grounded because of unavailability of engines from PW.

neutronstar73 · Wed Jul 12, 2017 8:57 pm

lightsaber wrote:
Lower altitude also reduces the peak temperature during climb. The NEO combustor are having durability issues and a lower initial climb helps. But step climbing would mitigate if always flying below maximum possible cruise. This sounds like solving two issues with one easy to understand set of rules.

Fuel burn doesn't effect combustor durability. It is peak temperature. Ironically, flying lower will run the combustor and turbine inlet guide vanes colder as it avoids an end of climb trap where the pressure drop across the combustor is reduced increasing temperature due to reduced cooling effectiveness.

Lightsaber

I think someone here on A.net was saying how the PW was going to beat the LEAP at service entry, how it would be ahead in performance, would be ahead of performance expectations, and the LEAP would be guaranteed to not meet performance, and be behind right out the box..........

And I vehemently disagreed. Wonder how that worked out....

I know Pratt and Whitney will get it sorted eventually, but the CFM appears to be the choice to have at the moment.

As I've said before, GE/CFM is well-preserved for the future. They have the lead in materials technology and when they decide to go to a geared fan, they'll be set. It's going to take the others a long time to match GE's and CFM's materials technology.

KarelXWB · Thu Jul 13, 2017 1:04 pm

dynkrisolo wrote:
As previously stated, IndiGo's VT-ITF, G, J, K,M, N, O and S are grounded, out of a total fleet of 22.

VT-ITU and VT-ITT are the most interesting aircraft to follow: both aircraft were delivered in May, after P&W introduced an improved seal for the number three bearing in April. Both are believed to be equipped with the improved engine.

flee · Sat Sep 02, 2017 6:00 am

neutronstar73 wrote:
I think someone here on A.net was saying how the PW was going to beat the LEAP at service entry, how it would be ahead in performance, would be ahead of performance expectations, and the LEAP would be guaranteed to not meet performance, and be behind right out the box..........

And I vehemently disagreed. Wonder how that worked out....

I know Pratt and Whitney will get it sorted eventually, but the CFM appears to be the choice to have at the moment.

As I've said before, GE/CFM is well-preserved for the future. They have the lead in materials technology and when they decide to go to a geared fan, they'll be set. It's going to take the others a long time to match GE's and CFM's materials technology.

The CFM LEAP-1A isn't without problems - however, these are probably minor teething problems and CFM are working to resolve them without the need to swap engines for major repairs and upgrades. From what I can gather, the LEAP 1-A is also meeting CFM's performance and fuel burn promises.

I tend to agree that the CFM LEAP is experiencing a more normal entry into service than their competitor.

SQ22 · Sat Sep 02, 2017 8:35 am

The altitude restriction has been removed. Please continue your discussion in the new thread:

viewtopic.php?f=3&t=1372693

Thread will be locked.

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