"...prior to level acceleration."
 

ICAO Annex B noise abatement climb procedure is set standard to 3000ft. The procedure is usually some thing like climb to 1500 ft at V2 plus 10, set climb thrust, then to 3000 ft at V2 plus 10 and commence acceleration to 250 kts with clean up. This is usually not a level acceleration though.

So where a chart calls for "Climb to 4000' prior to level acceleration" such as the COR2F Departure on 10-3b (Jepp) in Athens does, what does one actually do differently, and why? As much GENUINE info on this subject as is out there would be appreciated.

I'm assuming that you're querying the "level" acceleration bit?
As far as I'm aware there's no reason that you HAVE to perform a level acc. - all that the chart is signifying is that you may do so if you need/want to. As far as I know, the noise abatement procedures (both A and B) are actually designed for a level acceleration segment, basically to cover the engine-out case, but if all the donks are turning and burning there's no reason we can't do a climbing acceleration - it's entirely up to us. In the SID that you quote, the 4000' restriction is to keep you above the high ground in the vicinity - once you get to 4000' you will be able to accelerate in level flight and still miss the hills, even with an engine out. If they're all still in running order you are perfectly at liberty to continue the climb whilst cleaning up.

Hope I understood your question right (and that my gen. is correct :))

Thanks for the reply. My query is actually this: do we need to maintain V2 plus 10 until reaching the altitude published: in this case 4000', before commencing the acceleration, even if our normal acceleration is a climbing one? That is; instead of doing V2 + 10 to 3000', we go to 4000' and then accelerate??

The SID reads "Climb to 4000', prior to LEVEL acceleration." This might imply that aircraft which do not normally accellerate in level flight need not comply with this note!???

[This message has been edited by Rusty A300 (edited 18 March 2001).]

What I do understand, looking at this departure, is that if you do your acceleration and clean up it should only be done after 4000' even though your aircraft might be able to accelerate in the climb. I would rather follow the safe route and only start the acceleration at 4000' This is more a safety issue than a noise related problem.

I might be wrong!?

Dr know, I think you`re wrong. This is in my opinion solely a noise restriction. You see it mentioned in more SID`s and even in some go-arounds (CDG?). In my opinion you can start your acceleration from 3000`. The level acceleration bit is something from way back when the planes were wooden and the pilots from steel. :)

Makes an interesting discussion. Especially since almost everybody flies these types of SID's and Missed Approaches every day, without giving them any thought. We all just fly these acceleration segments the way we feel, or the way our own logic tells us is correct.

In the Jep Air Traffic Control section, on pages 236 and 237, is an extract from the Flight Procedures (Doc 8168) Appendix 1 - Acceleration Segments. After reading this document, it is clear that the note "Climb to ....(altitude/height) prior to level acceleration" is only used in the terrein clearance instance. This IS NOT a noise abatement procedure.

MY LOGIC, (which too may be wrong) tells me that a V2 plus 10 (all engines) or V2 (engine out) climb is required until passing the specified altitude!???

Anybody else care to comment, or does anyone have a more specific knowledge on this subject???

Might be right!

Looking at the terrain clearance for this departure!

Can anybody comment on their own experiences of this departure, or similar ones, and the exact profiles that they actually fly under these circumstances?

Rusty A300 - yes, you are right. You MUST maintain V2+10 till 4000' before beginning the acceleration.

I think you're right also that "climb to XXX before level acc." is only used for terrain considerations, though it may also be airspace-related in some places (ie to keep you out of a conflicting SID/STAR) - I don't think it has anything to do with noise abatement.

Unfortunately I haven't been to Athens for ages and can't remember this particular SID, but I would certainly maintain V2+10 until 4000' if departing to the north - from what I remember there are some high hills in that direction!

Well, I'll let you know if I find out the exact rule. In the meantime, I've been onto Jepp about it, and hope to have a reply in a day or two.

While we wait though, perhaps someone in the know could let us in on their info...?

[This message has been edited by Rusty A300 (edited 20 March 2001).]

Perhaps you are being required, for terrain clearance, to maintain best angle of climb (Height vs Distance travelled) rather than best rate of climb (Height vs Time ? To do this with flap extended you must maintain max climb thrust at V2 + 10 until you can safely accelerate to commence flap retraction when clear of the specified terrain.

How the hell do you maintain V2 +10 when you cutback at 1000 ft agl? See this is why you guys cost your airlines money when you set off the buzzer because nobody trains you how to fly Noise abatement procedures and how to turn away from the Mic points. I see an STC in this somewheres.

BEagle: clearly you've given the matter some thought; thanks. Which is more than can be said for 747FOCAL!!!

For his sake allow me to point out. Nobody mentioned 1000 feet. If you've ever flown an A300, you would know that the climb procedure which I described is not only bog standard, but a mandatory noise abatement climb procedure. Don't they teach you FO's anything at CAL? Haven't you heard of reduced thrust take off and climb procedures? (or does FOCAL stand for Forgot Our Climb/Acceleration Limits) For the record; my company hasn't rang the bells in the last seven years! Has yours?

As it turns out; Jepp have responded to my mail: OUR PROCEDURE IS THE ONE LAID DOWN IN THE GREEK AIP! That's the authority we were discussing here 747FOCAL; if you hadn't heard.

To the rest of you that responded to this mail; thanks for the educated input!

To 747FOCAL;Hope they never promote you to MY job! E.. S... A.. D..!!!!

Athens 10-4 old chart and I’ll let all know if there is any changes to it soon specify that "the minimum steady climb-out speed should not be less than v2+10 (in obscene of turbulence) up to 700’AAL, then reduce to normal climb thrust without acceleration up to 2500'". On all the SID’s (LGAT) there is a minimum climb gradient to be satisfied, as long as you satisfy that you are o.k. (Note the difference between without acceleration and level acceleration). So 700’ AAL you ask for climb power continue v2+10 to 2500AAL accelerate while satisfying the required gradient rate of climb up to the altitude specified then proceed normal. Remember at times you need the level acceleration to clean up like in the case of ENG Failure, don’t do it before that altitude (4000 in your case). In an emergency you can deviate from noise abatement procedures but you continue to fly the SID TO MAKE SURE THAT YOU CLEAR ALL OBSTACLES.


[This message has been edited by Royan (edited 20 March 2001).]

[This message has been edited by Royan (edited 20 March 2001).]

Rusty,

Just ignore the dude. He´s one of the wind up merchants on this site, and stupid childish posts is about all he has to show for here.
I seem to remember that he is some kind of engineer or, whatever.. Certainly not a pilot, and it shows in a lot of his comments.
747FOCAL, back to school now...!

Good on ya mates!

Nice to get some informative gen again; not to mention moral support!

I fly on B737 and our company procedure is to ignore these "climb to .... ft prior level acceleration". The reason is stated, because all missed appr. and departures are calculated with fixed min. climb gradients (something around 2,5%). As long as you can safisty that, you can accelerate and climb at once.
For airplanes like heavy x-weight B747´s etc. they have to watch that and to remain on v2+... until passing the constrained altitude.
You will find details of construction of dep.+missed app. in ths Jeppy and the aip´s of the country.
Needless to say, that in case of engine failure the obstacle clearence is most important. Is there are a special engine failure procedure for that ATH dep. runway?

Do you think that we should tell 747FOCAL that the 1000 feet acceleration height is a minimum value, NAW I guess not!

Mutt

When there is an obstacle problem there I would like to know more about your Company SOP - clean up altitude - when having an engine failure at
- V1
- after diversion point of eosid but still below safe altitude
Rgds Max

Level acceleration segments used to be required by Pans Ops in the construction of all SID and Missed Approach procedures. It had a fixed length of (from fading memory) 6NM, followed by a 1% climb segment right up to enroute safety, MSA or whatever the country deems appropriate.

It was based purely on ensuring terrain clearance. There was never any intention to require pilots to use it that way. It was merely a consideration for aircraft that couldn't sustain the required climb performance above a particular altitude.

Pans Ops no longer requires the use of a level acceleration segment. It was removed from the document quite some years ago. Sooo, either the SID in question has been in existence for many, MANY years, or has been designed to the old criteria because the procedure designer didn't have an up-to-date Pans Ops volume 2 book.

If the latter case is correct, it won't be a worry for pilots as deletion of the level acceleration segment was the only change.

Hmmm, just thought of another reason for use of this segment in a new procedure. Some authorities might actually prefer to retain it in their procedures. Certainly, if terrain isn't very restrictive, this isn't much of a problem. But, as a procedure designer myself, I can tell you that it used to be right b@stard to design it into any procedure!

Anyway, chaps, the bottom line is that if you don't need to use level acceleration, don't worry about it ... just keep on climbing.

------------------
Once a king, always a king.
But once a nite's barely adequate!