ICAO Noise Abatement Procedure

[George Yogi]

+ Takeoff Power and flap climbing at V2 plus to 800' AFE
+ Set Climb power at 800'
+ Constant speed climb to 1500' AFE
+ At 1500' reduce pitch , Accelerate and retract flaps on schedule
+ Constant Speed climb to 3000' AFE
+ At 3000' accelerate to 250 kts
+ constant speed climb to 10000' AFE

Above is an ICAO defined climb profile for noise abatement procedure for A320 aircraft.
Why flaps are retracted only at 1500' AFE ( Above Field Elevation) ?, If this profile is to be followed for a noise abatement , then pilots need a Higher Angle or gradient of climb , which will get reduced due to reduction in excess thrust supplied by config 1+F or Config 2 , so why this profile is not suggesting an early retraction of flap in sequence after reaching V2 speed plus or 500' AGL (which is standard) to get a higher gradient or Angle of climb ?

[sonicbum]

Hello,

which NADP are you referring to ? That would be a good start.

[MarkerInbound]

I think you're asking why don't you retract the flaps at a lower altitude? Remember distance is your friend for noise reduction. In order to retract the flaps you have to lower the nose to increase your speed and this lowers your climb gradient. You're only worried about the first 3000 feet of climb. The tech people have figured out you'll spend more time down low retracting the flaps even if you will have a better climb once they're up.

[Natstrackalpha]

Not withstanding departure procedures / SIDs / OCLs and OCHs, MSAs or SSAs -


Is there a panacea climb profile which would be the quietest (please don`t say shutdown the engines) - I was on the ground the other day and saw a nice BA flight out of EGLL and s/he flew over it was a 319 or 318 or a 320 - possibly a 318 anyway he was just trickling along - clean and looked nice and slow to my Earthbound eye he looked to be doing about 160 and he was quiet as anything - actually it might have been 180 or 190 but not more.


Would not 1,000 fpm do it with a nominal climb speed like - green dot - like, a speed which would not demand to much coal from the engines?


Why is distance your friend? Is it because you are going further away from the area of noise abatement?


I have seen some quiet climbs and some roaring climbs - they are kind of obvious. One can always tell when somebody is at full bore even at 28,000 feet -especially Tornados and F15s.


From the flightdeck though where everything sounds the same, most of the time, could there be a cool power speed roc combo that keeps it hushed?

[Mark 1]

It's been a while since I was involved with it, but I recall that the criteria for cut-back on departure etc was based on minimising the noise exposure contours based on noise/power/distance tables for the aircraft/engine combination and associated climb performance.

The Integrated Noise Model (http://www.faa.gov/about/office_org/headquarters_offices/apl/research/models/inm_model/) is a software tool for predicting community noise exposure.

There are over-riding constraints such as minimum engine-out climb gradients etc, but there will usually be an optimum point where the noise reduction for power reduction outweighs the increase in the contour due to the reduced climb rate.

[MarkerInbound]

Why is distance your friend?

Sound is energy, it dissipates over distance.