NADP2 procedures?

[Will]

Regarding noise abatement procedures, I spent some time looking online and reading through past posts on this forum, and I'm left with a question. If you try to fly noise abatement procedures according to the NADP2 protocol, how is that different from a normal takeoff in the 744?

I have found two answers to this question.

1. There is no real difference between NADP2 and a normal takeoff, as long as you set your acceleration height to something like 1000 feet, and your thrust reduction point to something like Flaps 5. Otherwise, NADP2 is just a normal takeoff.

2. It's a normal takeoff, except that you might hold the flaps up maneuvering speed a bit longer, delaying your acceleration to climb speed. For example, if you reach 2500 feel AGL at the flaps clean maneuvering speed, you would hold that speed, and delay accelerating until passing 3000 feet. (The exact altitude might vary by published airport procedures.)

To sum up: in a typical NADP2 scenario, do you always accelerate as per the FMC? Or do you sometimes delay acceleration until passing some defined altitude?

Thanks!

[Mariano]

Will,

At the company for which I work, a variant of NADP2 is the default procedure unless a local requirement calls for NADP1.

On our fleet of 747s (both the -400s and the -8s) the (NG) FMCs are set as below in the AIRLINE POLICY page 1/2:

THR RED
FLAPS 5

ACCEL HT
1000/1000

So, unless modified by the crew during the preflight procedure (because of local requirements or very specific high/complex terrain situations), VNAV will begin acceleration at 1000 ft. and thrust will be reduced at flaps 5.

If NADP1 is required, acceleration is edited to 3000 ft., and thrust reduction is edited to 1500 ft. (in the TAKEOFF REF pages).

On the 767, in some situations, we allow VNAV to begin acceleration as programmed, but speed intervene to hold a specific flap (setting) maneuvering speed until a (radius-limited) turn is complete. Sometimes we program this speed in VNAV CLB page if we can pair it with an altitude, or in the LEGS pages if we can pair it with a waypoint and an altitude as well (A/B). I believe that the NG FMC does not require an altitude if a speed is entered abeam a waypoint in the LEGS pages (very nice feature).

In the vast majority of takeoffs, we allow VNAV to do as programmed.

So, as for "...do you always accelerate as per the FMC?", yes, almost always we do (if programmed correctly).

I hope that I have answered your question (not sure that I have ;-).

Best regards,

Mariano