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Pilots describe tight airspace around Washington airport

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Planes have to avoid airspace around White House, Pentagon

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Army official questions military training near airports

(Adds details throughout)

By Allison Lampert, Rajesh Kumar Singh and Dan Catchpole

Jan 30 (Reuters) - U.S. commercial pilot Rick Redfern

was preparing to land at Reagan Washington National Airport

about a decade ago when he spotted a bright red Coast Guard

helicopter hovering about 50 feet (15 m) above the Potomac

River.

Air traffic control promptly warned the helicopter pilot to stay

clear, and Redfern said he used evasive maneuvers to avoid it

and avert a potential disaster - and that was in daytime, when

visibility was clearer.

At night "the light can disorient you as to what you might

think you are seeing as to what you actually are seeing,"

Redfern said.

A collision on Wednesday night between a Black Hawk military

helicopter and an American Airlines ( AAL ) subsidiary's CRJ700

regional jet, which killed 67 people, has stirred haunting

memories for Redfern and other pilots who have faced challenges

landing at the Washington airport.

Planes approaching the airport must navigate a precise and

narrow flight path to avoid restricted airspace around the

nearby White House and Pentagon.

"That turn from the eastern side along the river to turn into

runway 33 is very, very tight," said Redfern, referring to the

same airstrip the American Airlines ( AAL ) jet was heading towards

before colliding with the U.S. military helicopter.

It is unclear what caused the crash, which is now under

investigation by the U.S. National Transportation Safety Board

and the U.S. Army. Air crashes typically result from multiple

factors.

Seven U.S. pilots told Reuters the landing at Reagan airport is

unique due to congested space, along with an inability to

communicate directly with military aircraft, which operate on

different radio frequencies. The airport also has shorter

runways, including runway 33, which is generally reserved for

smaller aircraft, one of the seven aviators said.

For pilots, it means traversing narrow airspace, since planes

cannot cross the eastern shoreline of the Potomac River when

approaching the airport that is also used regularly by the

military for training, the aviators said.

The U.S. Army Black Hawk helicopter involved in the collision

was on a training flight and flying at an altitude of about 300

feet at the time of the crash, according to FlightRadar24 data.

To avoid collisions with other aircraft, pilots rely on the

Traffic Alert and Collision Avoidance System, better known as

TCAS. When TCAS detects a dangerously close aircraft, it gives

instructions to the pilots to avoid a collision, such as pull up

or descend, turn left or turn right.

However, when an airplane is below about 1,100 feet, TCAS stops

giving instructions to pilots.

"There just isn't enough room below that to maneuver," said

aviation safety expert and former airline pilot John Nance.

NEAR MISSES

A Reuters review of incidents at Reagan airport involving

helicopters reveals pilots had been raising alarm about

near-misses back to the 1980s.

"You definitely are bringing your A-game when you fly in and out

of Reagan," said former long-time commercial airline pilot

Kathleen Bangs.

Out of 46 incidents flagged anonymously by pilots in the

Aviation Safety Reporting System database, 26 cases involved

near-misses or recklessly close contact.

In a report about an incident in September 1989, one pilot

complained that military helicopters and commercial aircraft are

on different radio frequencies, cannot hear each other and rely

on "very busy" traffic controllers to prevent accidents.

The pilot complained it was his seventh near-miss with a

helicopter in 4-1/2 years flying into the airport.

"Is DCA (Reagan) a congested airspace? Yes, hands down no doubt

about it," said Dennis Tajer, a spokesperson for the Allied

Pilots Association that represents American Airlines ( AAL )

mainline pilots.

"It's in a very tight airspace because there are restricted

areas all around the airport."

While constrained airspace makes the approach more

challenging, aviation safety experts have not raised widespread

concerns about the space constraints.

"We have commercial flights and military flights and all

types of flights operating out of Reagan National every day,"

said aviation safety and crash investigation expert Anthony

Brickhouse.

A PREVENTABLE TRAGEDY?

In the moments before the crash, an air traffic controller can

be heard on recordings asking the Army helicopter to pass behind

the regional jet.

"They'll be studying what the helicopter pilots and

commercial pilots could have seen and any communication between

the two aircraft," Brickhouse said.

Commercial aircraft use Very High Frequency (VHF) radios to

communicate, while military aircraft operate on Ultra High

Frequency (UHF) channels, making direct communication between

them difficult. However, the control tower can communicate with

both frequencies.

"There are established procedures to separate commercial and

military helicopter traffic," said the general aviation group

Aircraft Owners and Pilots Association (AOPA).

Nevertheless, the collision may lead to changes.

Army Secretary nominee Daniel Driscoll said during a Senate

hearing on Thursday that the crash may prompt the military to

reconsider conducting training operations near the busy

Washington, D.C., airspace.

"This seems to be preventable," Driscoll said. "I think we

might need to look at where is an appropriate time to take

training risk, and it may not be near an airport like Reagan."