A320 Single Engine Climb Gradient

[Snecma]

I've been looking into single engine climb gradients at hot and high airports and have a question about the A320 with CFM's. How does it perform at hot and high airports, specifically in the 3rd and 4th segment climb?

Perhaps an example will help:
What is the single-engine climb gradient (% or fpnm) at MTOW, 28 degrees C, no wind, 8,500 ft pa airport (so 10,000 ft in 4th segment climb)?

Anyone with Airbus docs that can help me out?

[loc22550]

This is a theorical problem.

What you should known first is; are you are able to take off with your A-320from such an airport(8500 p.a, 28 degrees...) at MTOW...i doubt:bored:
That's why i would turn your question upside down:

What is my Max RTOW (regulated take off weight) for this 8500 p.a Airport, 28 degrees..(in order to fullfill the minimum climb gradient on one engine (2.4 % for the 2nd segment,1.2% for the 3rd segment))?
Performance Table or PC for this particular airport will tell you taking everything in consideration..obstacle....

[Old Smokey]

Straight from the Regularity Authority to you -

"In the en-route configuration existing at the end of the level flight acceleration
manoeuvre, an aeroplane must be able to achieve a gross gradient of climb of
at least:
(a) for a twin-engined aeroplane — 1.2%; or
(b) for a 3-engined aeroplane — 1.4%; or
(c) for a 4-engined aeroplane — 1.5%."

That describes the 4th segment. In the 3rd segment the climb required is zero, but the aircraft must have the CAPABILITY of meeting a 1.2% climb anywhere in the 3rd segment (It helps in a number of OEISID creation problems).

Obviously then, the A320 in your example must meet a minimum climb gradient of 1.2% Gross (0.4% Net), it will, of course, do better than this at lower weights.

That's from the Australian Regulations (CAO 20.7.1B), these fairly much 'parrot' the FAR and JAR requirements.

Regards,

Old Smokey

[Flyman35]

hello old smokey I am one of your fan I hope you are doing well and wish you all the best.:D

[Snecma]

I'm familiar with the minimum 2.4% for 2nd segment and 1.2% thereafter, but it's not a question of minimums. Will an A320 be able to fly a single engine climb gradient of 5.8% (350 fpnm) up to 16,000 ft from an airport pressure altitude of 8,500 ft? (28 degrees C, no wind, MTOW, CFM engines)?

If not, does anyone know at what TOW it would be able to achieve 5.8% on one engine?

I'd be willing to bet good money that it can't make 5.8% at MTOW, but would like some sort of confirmation before I make that bet ;)

[mcdhu]

Half the trouble is that for those of us with the Airbus laptop performance device (LPC), we can only perform calculations for airports on our network; it does not give us the facility to do the sums that you ask and there simply aren't any airports even close to that elevation in Europe that could accommodate the A320.

Having said that, I too am pretty sure that the answer is no!! Eg typical app/climb gradient at or around MLW in temperate climate with around 1000' pressure alt is 5%.

mcdhu

[rudderrudderrat]

I don't know where you'll find that information easily. I thought that once the aircraft was clean and MCT set, then all you have to do is climb in a safe holding area until you can definitely make the next MSA / MOA.

[Snecma]

rudderrudderrat,

You're absolutely correct. This is really a hypothetical situation that would never happen because after a lost engine, you'd return to the airport. Problem is, the people I'm talking to don't necessarily believe that. They think you should be able to continue the SID on single engine. Of course airplanes have run into cumulogranite with that mindset, which is why I'm trying to influence the change.

I'm trying to prove that they've been operating outside the safety margin, or more probably, they're not aware of exactly what their operations group is doing (it's not a group of pilots I need to convince, rather a group of execs).

Thanks all for your help. I'm certain enough that the Airbus can't maintain 5.8% single engine at FL100 to challenge them on it.

[PappyJ]

You're absolutely correct. This is really a hypothetical situation that would never happen because after a lost engine, you'd return to the airport.

Soooo, if the airport you just departed from was below landing limits....or you just left a bunch of debris on it's only runway.... or.... You'd return to that airport?

Funny, I seem to recall something about "Take-Off alternate within 60 minutes, blah, blah, blah...

Problem is, the people I'm talking to don't necessarily believe that.

And those people would be called.....Professionals?

They think you should be able to continue the SID on single engine.

The nerve of some people. How utterly absurd!

Of course airplanes have run into cumulogranite with that mindset, which is why I'm trying to influence the change.

Could you provide ONE example of this "cumulogranite' event where the SID was flown properly, aircraft operated properly and performance properly calculated?

[Pugilistic Animus]

hello old smokey I am one of your fan I hope you are doing well and wish you all the best


Old Smokey tends to get busy,...but we are all his fans on here:D

[Old Smokey]

Flyman35, Pugilistic Animus,

Aw shucks!:} Now I'm embarrassed, there's a GREAT many things that I don't know, Performance just happens to be my little niche. I avidly read other poster's comments on the great many things that I don't know.:ok:

rudderrudderrat, You stated (correctly) ".....once the aircraft was clean and MCT set, then all you have to do is climb in a safe holding area until you can definitely make the next MSA....."

The manoeuvre that you describe is otherwise known as the 4th Segment.:ok: (Which is what this thread is all about).

After leaving the MSA "protected" area for continued flight to another airfield, another set of "En-Route" requirements apply.

POST SCRIPT

Just to reinforce the very wise comments made by TRUE professionals on this and other threads, any pilot who believes that he/she can safely follow the SID with an engine inoperative is a BLOODY IDIOT!!!:* (Please advise the airline that you fly for so that I can add it to the "no fly" list).

Regards,

Old Smokey

[Pugilistic Animus]

I know what you mean O_S everyday that passes all I can say is "I wish I could just know much more....:)

[Old Smokey]

PA, I figure that I'll have just about enough knowledge to consider myself a complete professional about 1 day before I retire, which is just 1 year away.

Come to think about it, one year isn't enough, I'll probably have to retire with amateur status.:{

Regards,

Old Smokey

[john_tullamarine]

Come to think about it, one year isn't enough,

I find it intriguing that, for most of us who don't have too high an opinion of our innate knowledge .... start off knowing nothing .... a year or two later (as young bucks with a few hundred hours) know that we know everything .. and then spend the rest of our careers coming to realise just how little we really do know.

Those of us who might end up experts, of course, understand that an expert is someone who knows an impressive amount about next to nothing, a workmanlike amount about a number of other useful things .... and zip about near everything else.

Learning commences with humility.

OS, salut !