Departure profiles cutback and reduction altitudes

[MED1473 18]

Hi all!

Could anybody explain the difference between cutback and reduction altitude? it's not very clear atm

Thank you!

[hughesj2 0]

Matteo, check this article out..

 

http://www.boeing.com/commercial/aeromagazine/aero_21/quietclimb_story.html

[ctdesing 5]

Reduction Height with cutback off is the elevation at which autothrottle reduces from takeoff N1 to Climb N1. When cutback is on the reduction height is the elevation at which autothrottle reduces from takeoff N1 to Cutback N1, then at Restore height the autotrottle set Climb N1. Cutback N1 is lower than Climb N1 to comply with field noise abatement procedures. You can find more information on 737NG FCOM Flight Management Navigation Chapter.

[3-2-1-Now 126]

It's silly how they worry so much about noise from aircraft, yet there are cars that make far more noise driving by my house that are clearly breaking the law on noise limits, yet nothing ever gets done!

 

For the record, I find the noise from cars far more objectionable than the sound of any aircraft, at any time of day.

 

Best regards,

Robin.

[scandinavian13 5,192]

It's silly how they worry so much about noise from aircraft, yet there are cars that make far more noise driving by my house that are clearly breaking the law on noise limits, yet nothing ever gets done!

 

My senior project in college was all about noise and how asinine the whole deal is...

It's not that it's louder, it's that the noise is more identifiable. It's also that it isn't long enough to just give up and continue talking (highway noise), or short enough that it's "acceptable." Lawn mowers live in an in-between area. They're loud and annoying, but residents put up with them because a neighbor's jungle brings your property value down.

 

The only time people don't care about aircraft noise is when they're the ones on the plane. And then they get irritated that they can't land at DCA past the curfew and blame the airline...

 

Interestingly, in a study at IAD, the fewest complaints came from a quaint town off of Runway 30 that is affected the most by the noise. Most of the complaints came the well-to-do/new-money area of Ashburn, with moderate impact at best.

 

Stupid. Stupid. Stupid.

[kevinh 409]

I think it's more a case that aircraft noise is high profile and well publicised. People are less aware of traffic noise. Also near a busy airport the noise repeats at regular and frequent intervals. Aircraft are much quieter than they were in the 1960s yet people will still complain if they can even hear an aircraft, regardless of how intrusive the sound really is.

 

My family used to live near Heathrow up until the mid 1970s, just far enough away that we didn't qualify for a grant to install double glazing to reduce the noise impact. As an aircraft enthusiast the noise didn't bother me at all. I could identify different aircraft by the sound they made before they appeared overhead. In contrast my parents hated the roar of turbojet noise, but didn't mind the whistle of turboprops so much. It's very subjective.

 

Departure profiles which reduce aircraft noise footprint are worthwhile if only to show that the aviation business is doing what it can to reduce noise impact. In flightsim the different takeoff profiles add interest and variety to virtual flying.

[acko52 13]

You also get the people that buy a house, knowing full well that it is under a flight path of an airport, and then scream blue murder about the noise.

Ilive near an airport and can relate to Kevin about identifiing aircraft by their sound , and know instantly when some uncommon aircraft has taken off

Jeff

[scandinavian13 5,192]

You also get the people that buy a house, knowing full well that it is under a flight path of an airport, and then scream blue murder about the noise.

 

Yep. Welcome to Ashburn. Whole bunch of people moved out there in the .COM boom (90s). The airport has been there since the late 50s. Flights from the early 60s.

 

Same goes for Leesburg (JYO - where I fly). It was surrounded by farmland until the early 2000s. And then people put houses less than a mile from the runway (and wanted to put some even closer, but the town finally stepped in and did something - partially too late).

[dmwalker 612]

It's silly how they worry so much about noise from aircraft, yet there are cars that make far more noise driving by my house

 

I assume you are not living under the flightpath of a major international airport.

 

Interestingly, in a study at IAD, the fewest complaints came from a quaint town off of Runway 30 that is affected the most by the noise. Most of the complaints came the well-to-do/new-money area of Ashburn, with moderate impact at best.

 

Maybe the complaints were proportional to the populations. I believe these studies measure 24 hr average noise levels but I would think that it is the noise levels during the two minutes that the aircraft is flying overhead which are the cause of complaints.

 

I would estimate that a 747 taking off over my house, which is about 15 miles from the runway, would measure about 85 dB overhead. There used to be about five 747s one after the other each evening heading for the UK and Europe. Fortunately, patterns have changed and I think there are now less 747s these days and they don't fly over my house.

[scandinavian13 5,192]

Maybe the complaints were proportional to the populations. I believe these studies measure 24 hr average noise levels but I would think that it is the noise levels during the two minutes that the aircraft is flying overhead which are the cause of complaints.

 

I adjusted for time of exposure and complaints per cap. My stats prof didn't let me get away with half-[rear-ended] stuff. Arcola is the most affected, as IAD uses 30 for departures constantly. The arrivals and deps on the 19s are spread across the 3 (2 at the time) runways.

[acko52 13]

Usally the airport is there before the houses, as Kyle has said, and it is the case as regards to where i live.

They actually wanted them to move the airport to woop woop/ out in the sticks.

jeff

[dmwalker 612]

I adjusted for time of exposure and complaints per cap.

 

Were you doing your own measurements or were you analysing data from the Annual Aircraft Noise Reports of the MWAA? I like that they add 10 dB to the noise measurements between 10.00 pm and 7.00 am.

 

They actually wanted them to move the airport to woop woop/ out in the sticks.

 

It's a tough choice whether to build close to a large population of voters or to eliminate 5000 acres of prime agricultural land.

[scandinavian13 5,192]

Were you doing your own measurements or were you analysing data from the Annual Aircraft Noise Reports of the MWAA? I like that they add 10 dB to the noise measurements between 10.00 pm and 7.00 am.

 

A little bit of both. I had access to the AoA through a connection, as well, so I measured close readings on my own along with my own readings in the main neighborhoods (Assburn, Chantilly, Cville, Arcola, Reston, Herndon and so on). The MWAA data was added into that mix as well.

 

They do a good job of capturing the data here.