A turn in the approach path to minimise noise?

[uhb129b]

I always wanted to ask this from an ATC expert:

Is it possible to design a turning point into the approach path close to the runway in order to minimise the noise load on the population around the airport?

There is an airport where it would make a difference, if the landing aircraft would make a right turn of about 5-10 degrees as near as possible to the beginning of the runway. Currently, the final approach leads straight over a village, but if there was a turn in it, then the aircraft would fly a large portion of their approach over some corn fields. The closer the turning point would be to the end of the runway, the more the aircraft would be flying over the cornfields.

All comments are wellcome!

[normally right blank]

Just interested: Was the airfield there before the village? What kind of runway - length/users?
Best regards

[uhb129b]

Ex-military airfield. Military left 20 years before. It was peaceful and quiet, so people started building houses more or less illegally close to the runway. Airport complex was sold to an investor, who reopened it for commercial traffic. Since then there is a war between the involved around the noise. On one hand the airport brings good business to the village. On the other hand it is noisy.

Traffic is mostly low-cost (737 or 320). Some cargo with 744s. Roughly 35000 ATMs annually.

Runway is 3000 m.

[wiggy]

Most operators, certainly of the 747, would be most unhappy with a close in turn. In "my" oufit, a major 747 operator, it's a requirement that the aircraft's wings are level ( essentially, the aircraft is lined up with the runway) not lower than 300' above the runway, which equates to roughly one mile beyond the runway's end. In addition, whilst there are ATC let down procedures around the world which do contain a turning element (e.g. 13Left/Right at JFK) such approaches are unuseable in poor weather. If it's a 24/7, all weather airfield you are stuck with straight in approaches, all IMHO.

[120.4]

It is theoretically possible, although the aircrews wouldn't be too happy about it and would almost certainly refuse it in anything other than good wx.

From an ATC point of view: It would reduce the capacity of the runway in question. One of the reasons that Heathrow and Gatwick are able to squeeze so much capacity out of their pitiful runway resource is that we operate long finals. This creates a situation where the aircraft in the landing stream are set up in similar fashion (not identical, due to the wind gradient). That is to say, they are all on the same heading and on the final approach track. This gives ATC the opportunity to "see" the errors in vectoring and use speed differentials (usually 20kts) over an extended period to correct them. if you join the final short then ATC get no opportunity to correct vectoring errors (which there will always be) and the landing rate will drop. It is also much more difficult to apply wake vortex minima when traffic is not on the same track.

.4

[uhb129b]

Thank you for the responses!

I guess, the same considerations apply to making the approach steeper at the beginning and then align to the usual 3-4 degrees at the end. Is that true?

[Roffa]

Do a google on "offset ILS approaches" and see if that's the sort of thing you're thinking of.

Wouldn't be a quick fix though.

[Jerricho]

*Edited coz I was intoxicated*

[cossack]

He's talking arrivals not departures Jer:cool:

[Bern Oulli]

Well, presumably departures in the reciprocal direction cause even more of a noise problem, so a turn off the runway QDM asap after take-off might be an answer. In respect of arrivals however, wasn't MLS supposed to offer the possibility of a curved approach? Indeed, several different approach paths even.

[Jerricho]

RTFT Jerricho :rolleyes:

[begbie]

Like this!?

http://www.youtube.com/watch?v=LjRTy7yxAUs