"A Tango of mistaken identity"

Saturday, July 2, 2005

A Tango of mistaken identity 
Even with safety measures, pilots confuse Sea-Tac taxiway for runway 
BY JOHN GILLIE
The Tacoma (WA) News Tribune


Federal and local aviation authorities remain puzzled by a persistent case
of mistaken identity at Sea-Tac Airport despite their best efforts to avoid
it.

The case involves an airport taxiway that pilots have repeatedly mistaken
for a runway. Eight times in the last four years pilots have mistaken the
runway-like Taxiway Tango for the westernmost of Sea-Tac's two parallel
runways, Runway 16 Right.

Three times aircraft have landed on the taxiway. And five other times pilots
have noticed their error before landing and either aborted their landing or
corrected their course to land on 16 Right.

The airport hoped it had solved the problem a year ago. It painted the
taxiway end with a large yellow X, it had briefed pilots based here to use
more care in identifying their landing sites, it had issued notices to
pilots on approach maps and on a recorded advisory, and it equipped the
adjacent runways with daytime flashing runway-end identification lights.

Despite these precautions, a Southwest Airlines flight from Albuquerque,
N.M., to Sea-Tac lined up to land on the taxiway Jan. 30 this year.

Only when the flight was 250 feet above the runway level did the crew abort
the taxiway landing after the captain and the first officer noticed the "X"
painted at the taxiway end. The flight crews went around and landed on the
correct runway.

Johanna Forkner, Sea-Tac's manager of airport certification, said the
airport, the Federal Aviation Administration and the National Transportation
Safety Board have formed a task force to discover why the taxiway has been
repeatedly mistaken for a runway.

A team of experts has flown many approaches to Runway 16 Right to study the
lighting conditions and visibility. To duplicate the conditions present when
most of the incidents happened, the airport's firefighters have wet down the
taxiway. Many of the identification problems have happened after a passing
shower has wetted the pavement and then the clouds have cleared to bathe the
taxiway in bright sunshine.

"We found that under the right conditions, the glare just washes out the
markings at the ends of the runways and the taxiway," she said.

The runways are marked with large numbers painted on the pavement.

The misidentification problems have happened when pilots are visually flying
the plane to a landing, not when they are following their instruments. The
instruments typically warn pilots when they stray even a few feet left or
right of the runway.

FAA spokesman Mike Fergus said the briefings, the lights and the information
available to pilots should help prevent further incidents, but the federal
agency is keeping a close eye on the situation.

Forkner said FAA human factors engineers are working with the airport to
develop new methods of identifying the taxiway. The NTSB in a 2004 report
recommended the taxiway be painted with a serpentine stripe to further deter
landings. The airport is awaiting the task force's report to decide whether
that marking will be visible after a rain.

Landing on the taxiway now is not highly dangerous because of limited
activity there. The taxiway, which is as long as the adjacent runway and
nearly as wide, is used now only for access to the Weyerhaeuser corporate
hangars and to an aircraft tie-down area on the airport's west side.

The port, however, is building a third runway west of Taxiway Tango. Once
that runway opens in 2008, the taxiway will be much busier, raising the risk
of a collision much higher for planes that mistake the taxiway for a runway.

Sea-Tac Airport's Taxiway Tango

Length: 9,500 feet

Width: 100 feet

Location: 600 feet west of the airport's Runway 16 Right

Landings: Three commercial flights have mistakenly landed on Tango 

Source: Port of Seattle

Attached Photo:

Taxiway Tango

BIZ0702_taxiway_g.jpg