What is cutback? How does it affect takeoff performance?

[royski 0]

Hi Captains, What is cutback? How does it affect takeoff performance? Thanks in advance for the comments.

[Azapata87 173]

Well I don't know the full details of it but I believe it is used for noise abatement procedures on departure. Engine N1 is reduced at a certain altitude to reduce noise. When this happens a shallow climb is maintained until normal climb power is resumed. In this case the CDU shows power is reduced at 800ft and increased again at 3000 feet.

[Steven_Caffey 23]

Like Andres said, it's for noise abatement. An example is KSNA (John Wayne airport, Santa Ana, CA)

[danieln 0]

Well I don't know the full details of it but I believe it is used for noise abatement procedures on departure. Engine N1 is reduced at a certain altitude to reduce noise. When this happens a shallow climb is maintained until normal climb power is resumed. In this case the CDU shows power is reduced at 800ft and increased again at 3000 feet.

Actually while we are on this topic, I've always wondered with the NGX, whats the difference between EO ACCEL HT and ACCEL HT?

[victorlima01 4]

Engine Out accel heightMost cases of noise abatement that I have witnessed in RL had a thrust reduction at 1500 AFE and accel height at 3000 AFE. If I´m not mistaken that would be ICAO B. Don´t know how they choose between one or the other though. Whether the airport authority leaves it up to the airline or whether it´s a standardized airport-specific procedure (either ICAO A or :( that must be adhered to by all departing jet acft.

[Guest tonyf38]

I think the Cutback option is for pilots who smoke too much !!

Hahah. Good one.. Some airports have different procedures, you just have to look at the charts to see their noise abatement warnings and the airports often have a warning sign if you are in a noise sensitive area.. The pilot rooms also have posting of detailed procedures as well... ATC and safety have the authority over any noise abatement procedure, sometimes they can get ridiculous and can't be followed fully, but you do the best you can..Point your aircraft at this heading when holding short blah blah.. Darn Town hall meetings..

[Guest tonyf38]

I don't know about other countries around the world, but a lot of people here in the USA invent things to complain about.. That's my rant for the day.. :)

[ZKOKQ 986]

I don't know about other countries around the world, but a lot of people here in the USA invent things to complain about.. That's my rant for the day.. :)

They do in New Zealand Tony, they build a house near the airport, and complain about the noise. All it's life NZCH has been a 24hr airport, as US aircraft from Mcmurdo land and take off at any time of the day and night.. Why buy a house near an airport, if you don't like the noise<sigh>

[GraemeBr 0]

The automated cutback feature on the 737NG is discussed here. It is known as QCS (Quiet Climb System) http://www.better-gw...Quiet_Climb.pdf Graeme

[royski 0]

Thank a lot guys for the helpful replies. What is used to do for noise abatement is set V2+20 in the first 2 or 3 waypoints in the FMC legs page or according to the SID charts. After reaching 3000 ft then I accelerate to 250 kts. I will try this cutback option in my next flight...

[MrPlaneDriver 41]

They do in New Zealand Tony, they build a house near the airport, and complain about the noise. All it's life NZCH has been a 24hr airport, as US aircraft from Mcmurdo land and take off at any time of the day and night.. Why buy a house near an airport, if you don't like the noise<sigh>

Same here in Brazil. São Paulo, more specifically. Congonhas Aiport has been there since 1936, when there were no houses around it. Then the government started building houses around it and people moved in, knowing about the airport, the noise and everything else associated to it. Now Congonhas is forced to close operations between 11p and 5:30a in order to allow the dwellers to sleep. Go figure.

[SierraDelta 1,355]

So far 11 replies - and not a single one that thought about pointing the OP to page 0.00.29 of the Introduction and Use manual where CUTBACK is explained...

[Spin737 102]

Engine Out accel height Most cases of noise abatement that I have witnessed in RL had a thrust reduction at 1500 AFE and accel height at 3000 AFE. If I´m not mistaken that would be ICAO B. Don´t know how they choose between one or the other though. Whether the airport authority leaves it up to the airline or whether it´s a standardized airport-specific procedure (either ICAO A or that must be adhered to by all departing jet acft.

I think ICAO A and B have been replaced with NADP-1 and -2. Couple tweaks. I'm guessing the airport tells the operators which to use. Some airports have NADP-1 one taking off in one direction and NADP-2 in the other.

[victorlima01 4]

So far 11 replies - and not a single one that thought about pointing the OP to page 0.00.29 of the Introduction and Use manual where CUTBACK is explained...

Maybe because that's some people here like to dig deep into their minds and evoke procedures and lessons from their memory. You know, keep things active under the hood. I personally like to try and explain things my own way before replying "rtfm". Makes room for healthy discussions where a wealth of information is shared. They say it helps prevent Alzheimer's as well. As for ICAO vs. NADP, Matt is right. BTW I found these lying around. Don't know how accuarate they are though: http://www.b737mrg.net/downloads/b737mrg_noise.pdf

[royski 0]

Maybe because that's some people here like to dig deep into their minds and evoke procedures and lessons from their memory. You know, keep things active under the hood. I personally like to try and explain things my own way before replying "rtfm". Makes room for healthy discussions where a wealth of information is shared. They say it helps prevent Alzheimer's as well. As for ICAO vs. NADP, Matt is right. BTW I found these lying around. Don't know how accuarate they are though: http://www.b737mrg.n...37mrg_noise.pdf

Thanks a lot Captain!