"Targeting airport noise"

Saturday, March 15, 2003

Targeting airport noise
Louisville test of new approach shows promise
By Chris Poynter
The Louisville (KY) Courier-Journal


Louisville International Airport may have found a new way to significantly
reduce airplane noise -- by keeping planes higher in the sky just before
landing.

Tests conducted at the airport with United Parcel Service planes last fall
showed a marked noise reduction in areas seven to 30 miles away and could
have national implications for airports dealing with noise problems, said
airport general manager Jim DeLong.

''If this proves successful in Louisville, it could be common throughout the
country in five years,'' said DeLong, who helped oversee the tests to prove
a theory by a Massachusetts Institute of Technology professor.

The theory involves a change in landing procedures. Planes currently begin
their Louisville descent at 11,000 feet, then level off at 3,000 feet and
cruise for several miles before making a final descent.

The cruising is noisy for people living as far as 30 miles from the airport
because planes must use propulsion to maintain altitude.

Under the new method, there is no cruising, and planes simply follow a
direct and continuous descent path for most of the landing. Because the
planes are higher in the air, it is quieter on the ground.

This type of landing has been shown to reduce noise in neighborhoods that
are seven to 30 miles from the airport. Since many planes landing at
Louisville International come from the north, Southern Indiana neighborhoods
would benefit especially.

The new approach would not help neighborhoods within seven miles of the
airport -- such as western Louisville, Old Louisville and downtown --
because the planes' level at that point would be the same as now.

John-Paul Clarke, the MIT professor whose theory prompted the testing,
cautioned that ''we are a few years away'' from having the approach
universally accepted. But, he added, ''I am hopeful this would be used
nationwide.''

A spokesman for the Federal Aviation Administration agreed it's too early to
say if the tests could have further implications. ''It's important that the
group do further study,'' said Chris White, of the FAA's Atlanta office.

That's exactly what is being planned.

U.S. Rep. Anne Northup, R-3rd District, secured $850,000 in this year's
federal budget to continue tests -- either at Louisville International or
other airports nationwide.

Northup said she hopes the study will ''help airports across the country
expand their cargo and passenger services, while lowering noise pollution in
surrounding neighborhoods.''

If the new approach were adopted, passengers would not notice a difference,
except that the landing would be quicker, said Dennis Roberts, the airport's
deputy general manager. Up to 100 seconds can be shaved off the landing
time -- and there's no leveling off.

''Passengers will stop wondering why they're sitting in the air forever,
cruising at a low altitude,'' Clarke said.

Locally, tests were conducted last fall with help from NASA, Boeing and the
Federal Aviation Administration, among others. NASA brought to Louisville
highly sensitive noise monitors.

According to data released in the last few weeks, monitors placed at seven
points in Southern Indiana showed a reduction in noise of between three and
six decibels -- which is noticeable to the human ear, Roberts said. A
reduction of 10 decibels, for example, would cut the noise in half.

''These are fairly significant changes in noise levels,'' Roberts said.

That's good news for Bill Fender, a Floyds Knobs, Ind., man who finds
airplane noise irritating.

''It's nice to hear that somebody's listening and putting an effort to make
life around airports better,'' he said.

The potential new landing procedure is possible because of advances in
technology that allow computers to guide planes on landing, said Clarke, who
has been researching his theory on reducing airplane noise for several
years.

He first tested his theory in computer flight simulators, then got his
chance to prove it by using real planes after meeting DeLong, chairman of
the FAA's environment and energy subcommittee, two years ago.

Over a two-week period in late October and early November, two UPS planes
arriving from the West Coast -- and equipped with high-tech Flight
Management Systems -- tested the theory.

The first plane used the normal landing approach, while the second did the
direct descent.

They were separated by a few minutes, so weather and wind conditions were
consistent.

Jim Walton, a UPS captain involved in the tests, said the new approach is
less work for the pilots because it's computer controlled. ''It's primarily
on autopilot,'' he said.

But not all planes have the latest Flight Management Systems.

Walton also noted that this was a controlled experiment -- and implementing
the landing procedure with numerous planes coming in at all times of the day
would prove trickier.

DeLong said the new landing procedures also mean more work for air traffic
controllers because not all planes descend at the same rate. Under the
current method, air traffic controllers can have planes stairstep down and
cruise, then give pilots the signal for when to land. That method gives them
more control over planes.

DeLong said the new method makes that work ''much more difficult.''

The tests showed that, in addition to noise reductions, the direct descent
approach shaved up to 100 seconds off flight time and saved about 75 gallons
of fuel over the conventional approach.

''Mainly what this does is reduce operating costs,'' Walton said. ''And it's
part of being a good neighbor if we produce less noise.''

Attached Photo/Graphic:

The approach might cut noise in areas seven to 30 miles from the airport,
but wouldn't help closer neighborhoods.

Flight Patterns.

louisville1.jpg

flight_patterns.gif