COMAC C919

Info on Leap-1C engine from the manufacturer.

An environmentally-friendly engine​

Designed to meet the challenge of decarbonizing air transport, the LEAP-1C engine offers COMAC C919 operators enhanced performance in terms of fuel consumption and CO2 emissions (15% lower, note1), NOx emissions (up to 50% lower, note 2) and noise (in accordance with Chapter 14).

1. Compared to previous-generation engines.
2. In accordance with the ICAO’s CAEP/6 environmental standard.

Full info in below official site:-

taxiya said:

There was a question about A320's "impressive" range advantage over C919 in this thread. Today for an unrelated reason, I happen to read wiki page of A320neo again and noticed this highlighted texts.
View attachment 106993
The ACTs give 24% increase of fuel capacity. Question for people to think, is the "impressive" range achieved by the additional fuel tanks? I think very likely.

However the wiki figure about C919 has nothing about any additional tanks. If we calculate the max takeoff weight minus the operating empty weight and fuel capacity, there is a more than 2 tonne gap between C919 and A320neo. Is't ACT uncounted for? If so what is the fuel capacity of C919's wiki range? Or maybe COMAC sees no reason for C-919 to fly as far as A-320 therefor choose to give more rooms to the passengers and cargo.

My conclusion is that C919's performance is UNKNOWN. People should not take the western "experts" and Wikipedia for granted. Nor should people automatically believe that China is always behind the west for unknown or unexplained reasons without carefully examine available data.

Also worth to note, C919 is to be able to operate from Tibetan plateau. Many A320 variants can NOT do that. China uses an A319 variant with 120kN thrust for the purpose. A319 is 75.5t max takeoff with 120kN, C919 is 75.1t with >129kN.

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Well, they just did the SYX->HRB test. That's one of the longest flight you can do in China. And it did this in the dead of winter when there are often heavy wind that cuts range in one of the directions. The only remaining flight I would like to see it do is SHA->URC. Flight range normally reduces going West due to earth rotation and wind. So that would be a tougher flight to complete. If it can do that one, then it can basically do every domestic flight.

I don't think we should be concerned about much higher range. Airbus added A321LR and then A321XLR so that they can operate across the Atlantic Ocean even during the coldest winter months. I don't see the same demand for MU. Where does it need an 8 hour range aircraft to fly to? PVG->SIN might make sense, but is C919 certified to fly into Singapore? If it just stays inside China, why does it need more than 6 hour flight time range?

The bigger issue is cost per seat. We will see how it works out. Based on my previous calculations, its weight per seat numbers look comparable to A321NEO. Beyond that is a bunch of operational, maintenance/servicing numbers that we just don't know yet.

tphuang said:

Well, they just did the SYX->HRB test. That's one of the longest flight you can do in China. And it did this in the dead of winter when there are often heavy wind that cuts range in one of the directions. The only remaining flight I would like to see it do is SHA->URC. Flight range normally reduces going West due to earth rotation and wind. So that would be a tougher flight to complete. If it can do that one, then it can basically do every domestic flight.

I don't think we should be concerned about much higher range. Airbus added A321LR and then A321XLR so that they can operate across the Atlantic Ocean even during the coldest winter months. I don't see the same demand for MU. Where does it need an 8 hour range aircraft to fly to? PVG->SIN might make sense, but is C919 certified to fly into Singapore? If it just stays inside China, why does it need more than 6 hour flight time range?

The bigger issue is cost per seat. We will see how it works out. Based on my previous calculations, its weight per seat numbers look comparable to A321NEO. Beyond that is a bunch of operational, maintenance/servicing numbers that we just don't know yet.

Click to expand...

SHA-URC already done.

PopularScience said:

SHA-URC already done.

Please, Log in or Register to view URLs content!

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nice, that would be an even longer block hour day than the HRB, SYX flights.

taxiya said:

There was a question about A320's "impressive" range advantage over C919 in this thread. Today for an unrelated reason, I happen to read wiki page of A320neo again and noticed this highlighted texts.
View attachment 106993
The ACTs give 24% increase of fuel capacity. Question for people to think, is the "impressive" range achieved by the additional fuel tanks? I think very likely.

Click to expand...

There are 2 versions of C919. The basic C919 and extended range version C919ER. Their MTOW (and a little surprising, the OEW) is the same, but C919ER carries more fuel, should be something like ACTs.

taxiya said:

However the wiki figure about C919 has nothing about any additional tanks. If we calculate the max takeoff weight minus the operating empty weight and fuel capacity, there is a more than 2 tonne gap between C919 and A320neo. Is't ACT uncounted for? If so what is the fuel capacity of C919's wiki range? Or maybe COMAC sees no reason for C-919 to fly as far as A-320 therefor choose to give more rooms to the passengers and cargo.

Click to expand...

Wiki gives the specification of C919ER carrying 15 tons of commercial payload. Same for A320neo. Two reasons for this: 1. A320neo's structure is lighter, 2. Airbus may have played some tricks on the Payload/Range diagram.

The Payload/Range diagram is more reasonable than the figures on the brochure. Manufacturers prefer to use extreme operational conditions for advertisement. Some may reduce the time for diversion and go around. Even further, reduce the presumed body weight of passengers.

taxiya said:

My conclusion is that C919's performance is UNKNOWN. People should not take the western "experts" and Wikipedia for granted. Nor should people automatically believe that China is always behind the west for unknown or unexplained reasons without carefully examine available data.

Click to expand...

When COMAC finished the flight test, they release the ACAP file on their website. The characteristic of aircraft is quite clear then. Here is the link:

Here is an article (in Chinese) comparing the performance between 737max8, A320neo and C919ER:
Several points worth noticing:
1. The C919ER is not optimized. It is heavier than the competitors, which further lowers its payload. The calculated fuel efficiency is 10-15% lower than its competitors.
2. In the Payload/Range figure of C919, COMAC gives a very detailed description of the typical flight mission, compared with its competitors.
3. Although not as good as 737max8 and A320neo, C919 still shows better fuel efficiency over B737NG and A320ceo.

taxiya said:

Also worth to note, C919 is to be able to operate from Tibetan plateau. Many A320 variants can NOT do that. China uses an A319 variant with 120kN thrust for the purpose. A319 is 75.5t max takeoff with 120kN, C919 is 75.1t with >129kN.

Click to expand...

For C919, it is an initial requirement to operate on Tibetan plateau. But A320neo can do that too, as they finished the test successfully many years ago. However, many Chinese carriers keep buying A319neo, so far the only operators for this type in commercial aviation.

by78 said:

Spotted in Harbin.

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From the hottest region to the coldest region, I guess the difference of the ground temperature reaches 50 degrees lol.

taxiya said:

The ACTs give 24% increase of fuel capacity. Question for people to think, is the "impressive" range achieved by the additional fuel tanks? I think very likely.

Click to expand...

Again, nope:

taxiya said:

However the wiki figure about C919 has nothing about any additional tanks. If we calculate the max takeoff weight minus the operating empty weight and fuel capacity, there is a more than 2 tonne gap between C919 and A320neo. Is't ACT uncounted for? If so what is the fuel capacity of C919's wiki range? Or maybe COMAC sees no reason for C-919 to fly as far as A-320 therefor choose to give more rooms to the passengers and cargo.

Click to expand...

I'd be very wary of Wiki specs for aircraft, especially a question as complex as OEW - Airbus doesn't normally publish this info, as it depends so strongly on customer cabin fit. If you look at the A320 family ACAP, they have an insane variety of MTOW variants already, the situation with OEW would be worse still. Note how OEW is almost the only line without a reference to cite...

Credit where it's due though, the figure is probably in the right ball park compared to the C919 ACAP value, the writing has been on the wall for a while that the aircraft was going to be somewhat overweight. Most recently Leeham picked up and reported indications to that effect and years ago during development Aviationweek stated weight was over spec at the time. With the other weight goals being deliberately chosen within +-200kg of certain A320neo weight variants, one might logically assume the OEW target was very close too.

It's also possible to extrapolate a rough estimate from other known info and it seems something around 2t OEW difference (all else equal) is plausible. It is possible that, as Mischa says, the payload/range diagram could be distorted by Airbus positing different reserves (which, unlike COMAC, it doesn't explicitly state). But the assumptions for the C919 are not especially generous, so that is not going to be a huge difference even if the A320 data incorporates only the bare minimum.

taxiya said:

My conclusion is that C919's performance is UNKNOWN. People should not take the western "experts" and Wikipedia for granted. Nor should people automatically believe that China is always behind the west for unknown or unexplained reasons without carefully examine available data.

Click to expand...

Yes, the exact performance is subject to too many variables to be precisely known, but there are sufficient indications to conclude that it probably has somewhat shorter legs than the A320neo in a like-for-like comparison. It should still get the job done, certainly for the domestic market.

Mischa said:

From the hottest region to the coldest region, I guess the difference of the ground temperature reaches 50 degrees lol.

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Yup, big countries are funny like that I've driven by car through a temperature range of 50°C in the space of 3 days in the USA (early morning Red Canyon to afternoon Death Valley)! And that's with a day's layover along the way included - you could quite feasibly drive that route in one day.

tphuang said:

Let's not get into conspiracy theory here. C919 program will have many issues like this. Teething issue with regard to propulsion is quite common for new aircraft.

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I don't know how common it is, but one source is now reporting that it's unusual enough that it may force the launch date to be pushed back.

That's convenient for Comac's Western competitors.

It's also confirmed that the source of the problem was with GE components.

"Air engineering experts said that although a failure in thrust reversal is not a big problem, China Eastern probably will have to push back the plane’s commercial launch. They said an initial investigation found that the failure was caused by some problems in foreign-origin parts.

Those parts are produced by CFM International, a 50-50 joint venture between American GE Aviation and French Safran Aircraft Engines."

The thrust reverser malfunction is not a big problem and it is common in CFM engines.
But it is still a malfunction and should be eliminated.