A320 family engine question

Hey guys,

A little bit of a dumb question, but this has been nagging me for quite a bit.

Is the CFM56 engine on the A320 different from the one on the A321? I’m asking in terms of just looks, I know the performances are different.

I was recently spotting at MSP, and I couldn’t help but feel like they were different sizes.


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The CFM56-5 engines used by the A320 family have different internal variations. And none of those variations are limited to just one A320 family member. But all those variations only differ internally (different pressure Chambers, fan casing etc). The only distinguishable difference is that the engines for the A321(and I think the A320 too but it wasn’t applied as much) have the options to add chevrons(as seen on all Delta A321s and some American Airlines A321s) for noise reduction.

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same engine, albeit there are slightly different versions as you move through the years. outward size is the same tho

are you seeing the iae engines as well and perhaps comparing those to the cfm engined a320s?

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@ATK @airjonathan1

Hmm I see

I was looking back and forth between the (both delta) A320 and A321, and it almost seems as if the A321 has a bigger CFM engine in it. I’m aware that they’re both a 56-5B , so perhaps the nacelle is different?

Alternatively, I may need to have my eyesight checked :)


So I solved the mystery actually, so it turns out, all of delta’s A320s (ex Northwest) are rather old, so they all have the CFM56-5A variants. Delta’s A321s are all obviously rather new, and have the more advanced versions of the CFM56-5B engine. And according to wikipedia (https://en.wikipedia.org/wiki/CFM_International_CFM56), The 5B has “a new fan in a longer fan case, and a new low-pressure compressor with a fourth stage (up from three in earlier variants)” In other words, it’s got more stuff inside, making it bigger.

These CFM56-5B engines can produce at most 10,000lbs of thrust more than the CFM56-5A.

And you guys are not wrong either, Most of the newer A320 family aircraft (Including 319 and 318) are built with a variant of the 5B model. I just happened to see an older A320.

Thanks for your help!

Edit #2,

The A320 family in IF all have the CFM56-5B engines


The differences in engines on the A32X family are based on thrust rating-to get different ratings on the same engine, they use what’s called a thrust rating plug-basically a circuit board that tells the engine “output this much maximum thrust”

As for physical differences, you’re slightly correct. The CFM56-5(A) which powers the A319/A320 and the CFM56-5B which was designed originally for the A321, but yet powers the A320 family overall are about 7” apart in length and of course have different thrust ratings.
Check under specifications here:

Also have a peek here

Found specific differences listed.

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Wow nice reply!

Thanks for the help, I learned something really cool today.

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So did I! I was aware of the thrust ratings etc. also, you can tell which specific version of an engine an Airbus aircraft has by the designator code (way cooler than Boeing’s code imo)

You likely saw an A320-211 and then an A321-211 versus seeing an A320-214 which would have the CFM56-5B instead of the 5A

Here’s a list of the version codes for you


Yep, I hopped over to Airfleets just to check.

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This is a better code version. I was just looking on FR24 and I saw multiple Delta A320-211’s and -212’s

Interesting with the variant codes, I never knew they actually meant something. Does Boeing do a similar thing with their codes?

Boeing uses a customer code. Ryanair as an example is “Aircraft” B737-8(00) and then customer code instead of “00” which in this case is AS. So a B737-8AS is a 737-800 flying for Ryanair.

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Adding to what @emil said(which is 100% correct), Boeing stopped doing this after the arrival of the 787 and every new aircraft type after that. So if Ryanair ordered a 787-8 it would just be a 787-8 and not a 787-8AS.

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@emil @airjonathan1

Ah that makes sense. You guys know so much more than me, thank you!

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