Noise abatement procedure

[Walter Kranl]

Hi,

What are the typical values for thrust reduction height and acceleration height to perform a noise abatement procedure with the 744?

The procedures itself are described as follows:

Noise abatement departure prodecure 1 (NADP 1) =
noise reduction in close proximity to the departure end of runway.

- Thrust reduction height: 800 - 1000 ft
- Climb with V2 + 10 to 20, remain takeoff-config
- Acceleration height: 1500 - 3000 ft, retract flaps/slats on schedule


Noise abatement departure procedure 2 (NADP 2) =
noise reduction in a distance from the airport.

- Thust reduction height: at the initiation of the first flap/slat retraction or
   when zero flap/slat config is attained or
   at a specific height
- Climb and accelerate to Vzf (mimimum safe manoeuvring speed with zero flap)
- Acceleration height: 800 - 1500 ft

Walter

[tango4]

Hi Walter,
All i can give you is what we use at LFPG:

We have NADP1.
Take Off Thrust until 1500ft AFE
Acceleration to 250kt at 3000ft AFE (you can request more than 250kt if you are heavy and need it to clean the airplane, this will almost never be refused. And sometimes ATC can ASK you to increase to more than 250kt for traffic reasons).

Not much information, but that is a start !

Charles

[Hardy Heinlin]

Hi Charles,

what would be the reason to refuse 250+ kt? I see the only options for the poor crew would be to defuel or to wait until 250+ is possible again.


|-|ardy

[tango4]

Actually, 99% of the time, you won't say NO, you just want to be aware of it, especially if it is "significantly " more than 250kt (let's say closer to 270; of course, I won't see any difference if you increase to 253kt !).
I'm interested in knowing it because first of all, the aircraft might take longer to accelerate, and so climb poorly for "longer" between 3000ft and reaching that speed. And then it might be faster than the other aircraft ahead.

The only reason that I have sometimes refused more than 250kt (but really not frequently) is when the aircraft is in a big regulation (for example number 3 or 4 on a given departure, and I am in a situation when I don't have much space to work with). But to be honest, in those cases, I will not only refuse this request, but perhaps limit the aircraft to something like 220/230kt for a while to get some "breathing space". But as you mentioned, I know it is quite penalizing for the aircraft so this is really rarely used.
At CDG, we are supposed to transfer our aircraft to PARIS ACC 8Nm apart if they depart on the same SID. If they takeoff from the same runway, well, OK (even if they depart very close to each other).
But we have departures on 2 runways, and we also integrate traffic from LFPB (LeBourget) and LFOB(Beauvais).
Our runways are basically east west.
Here is a quick example: we are facing east. You can have a RANUX departure (eastboud) from 09R, another one from 08L, another one from LFPB, and another one from LFOB, almost at the same time. And you can then have another wave of RANUX from 09R immediately afterwards. As we are facing east, and this is an eastbound departure, you might find yourself in  a situation where you are "out of airspace" to separate your aircraft with headings and need to be a bit more agressive with speed control.

Hope this answer was clear enough, tell me if you did not understand something.

Charles

[tango4]

I am at work right now and just took a few pictures to illustrate what I just said above.
This was not rush hour of course, so it is just to give you an idea of what I was talking about.

https://www.dropbox.com/s/wzp3k5lnijui28p/20160719_145642.jpg?dl=0
https://www.dropbox.com/s/g5vleo78f915n4t/20160719_145911.jpg?dl=0
https://www.dropbox.com/s/vuys5j0nrl7whbr/20160719_150606.jpg?dl=0

Look at BRU866 (Belarus Avia) and DLH2J. These are two RANUX departures. (BRU is RANUX1H, DLH RANUX1G)
First picture, you see them on the ground radar, just about to take off, first BRU866 from runway 08R (08L is closed for 4 months for maintenance), then DLH2J on runway 09R.
Second picture, you see them just airborne.
Third picture,they have been sent to PARIS Control. On the third picture, you see a green cross between them. This is the waypoint NEPAR. The "contract" with Paris is that we are supposed to send them with at least 8NM separation, enroute to NEPAR, no catching up, cleared to FL190.

This example of course is the perfect one, where you only have these 2 aircraft to deal with on the RANUX departure. And the towers (North tower and South tower) coordinated correctly to send them "staggered", basically not releasing them so that they are in parallel.
Now imagine the same situation with another RANUX from LFPB (you can see the runways on the radar just southwest of LFPG), another one from LFOB, and, a situation where the towers failed to coordinate (because they forgot for some reason, or because they had to takeoff, etc. I won't go into too much details but it happens for various reasons) so that the BRU and DLH are just abeam each other, plus some other RANUX taking off after that.... Whole other story !

Hope this helps !

Charles

[Hardy Heinlin]

Thank you, Charles.

what would be the reason to refuse 250+ kt? I see the only options for the poor crew would be to defuel or to wait until 250+ is possible again.

What I wrote in this quote is pure nonsense; I was forgetting that the aircraft has flaps :-)

(In the back of my brain I was thinking of a speed limit below flap 20 speed.)

[tango4]

Well, you should get some sleep !
Hope you don't end up mad with this 10.0.9 update.
Once again, my consumption of aspirin has gone very high just trying to follow all your discussions with Peter and Jon...
Lots of headaches but very interesting !

[Walter Kranl]

Thank you Charles!
Just curious, what's the meaning of the black airplane symbols marked with "Z" (picture 2 and 3)?
METAR information ZULU ?

Walter

[tango4]

No, actually, each aircraft has a label with with a letter and a color associated to sort them out by "family" of flight.
The Z aircraft (black ones) are VFR aircraft that we do not control but need to visualise.
The aircraft I'm talking about are labelled ER for Eastboud departure Ranux SID.
But basically, each control center has its own way of sorting things according to their local needs.

Charles

[Icarus747]

We use:

NADP1=1000/3000

NADP2= 1000ft/Flaps 5 selection

The Airport Ref pages in the Jepps will outline other procedures per airport.

[Michael Benson]

At Slough Intl there is no prescribed NADP, it is left to crews to pick a profile which attains the requirements as listed on the SID, for example:

Cross Noise Monitoring Points not below 1083 QNH (1000 QFE) thereafter maintain minimum 4% climb gradient to 4000 to comply with Noise Abatement requirements.

In order to do this on the jumbo at Big Airways they fly the following profile

- Carry out standard takeoff procedure up to 1,000ft AAL.
- At 1,000ft AAL reduce to full CLB power.
- Speed intervene at flaps 10 min manoeuvring speed.
- Accelerate to F10 min manoeuvring speed, retracting to F10 on schedule.
- Climb at F10 min manoeuvring speed to 4000ft AAL.
- Terminate speed intervention, accelerate and retract flaps on schedule.
- Once clean, reduce to CLB1 power.

[cavaricooper]

Peter-

In re-

In order to do this on the jumbo at Big Airways they fly the following profile

- Carry out standard takeoff procedure up to 1,000ft AAL.
- At 1,000ft AAL reduce to full CLB power.
- Speed intervene at flaps 10 min manoeuvring speed.
- Accelerate to F10 min manoeuvring speed, retracting to F10 on schedule.
- Climb at F10 min manoeuvring speed to 4000ft AAL.
- Terminate speed intervention, accelerate and retract flaps on schedule.
- Once clean, reduce to CLB1 power.

Could you clarify re BA please, I was using Flap 10 + 10 selected. Charles sees this daily so has there been a change...or am I generalizing EGLL procs?

Ta!

C

[Britjet]

Carl,

The initial speed is flown at V2 plus 10 as normal, then, once you start the flap retraction...
There is no need for plus 10 on the speeds. That is a legacy of Classic philosophy.
You fly the flap 10 bug up to 4000 agl (unless it's bumpy etc).
Some BA noise abatement departures "terminate" at 3000 agl.

Peter.

[cavaricooper]

Brilliant, my Oracle at Delphi

Ta!

C

[Icarus747]

I also wanted to add, asking for a high speed climb in Germany (over 250) will be denied even if you say it's for safety.  We used to do this all the time.  The problem becomes they are giving permission for airspace they don't control.  So it's 250 up to 10K.  If there's terrain just leave some flaps out so you can turn steeper.