noise abatement

[mstram]

Ok, I'm not flying jets (yet ;) ),

but I'm curious, what is the difference between these two procs, and
what kind of planes would which one, (when if both) ?

What would a 767 use ?


Mike

========

From the Canadian Air Pilot - GEN

VNAP (Vertical Noise Abatement)

Procedure 'A'

===========

Take-off to 1500' above aerodrome elevation

- take-off power

- take-off flap

-climb at V2 + 10 to 20 kt (or as limited by body angle)

At 1500':

- reduce thrust to not less than climb power/thrust

1500' to 3000':

- climb at V2 + 10 to 20 kt

At 3000'

- accelerate smoothly to enroute climb speed with flap retraction on

schedule

Procedure 'B'

===========

Take-off to 1000' above aerodrome elevation

- take-off power/thrust

- take-off flap

-climb at V2 + 10 to 20 kt

At 1000':

- maintain a positive rate of climb, accelerate to zero flap minimum

safe manoeuvering speed (VzF) retracting flap on schedule

therafter:

reduce thrust consistent with the following:

a) for high bypass ratio engines, reduce to normal climb power/thrust

b) for low bypass ratio engines, reduce power/thrust if practicable to

below normal climb thrust but not less than that neccessary to maintain

the final take-off engine-out climb gradient: and

c) for aircraft with slow flap retraction, reduce power/ thrust at an

intermediate flap setting

thereafter

From 1000' to 3000'

- continue climb at not greater than VzF + 20 kt

At 3000'

- accelerate smoothly to enroute climb speed using normal climb

power/thrust

[Tor]

The first procedure gets you up fast - a lot of noise at a local area for some time.

The other gets you away fast - a lot of noise but distrubuted over a larger area.

Which procedure that is used depends on the surroundings - correct me if I'm wrong.

And a little joke:

"Flight 103, descend FL290"
"Roger, leaving 330 for 290 ... what's the reason for that, Sir ??"
"Noise abatement"
"Noise abatement ??? We're cruising at high level Sir, what kind of noise abatement ???"
"I know, I know. But there's opposite traffic at level 330 ... and there will be a LOT of noise if you both meet at FL330 !!!"

:)

[This message has been edited by Tor (edited 11 April 2001).]