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Monday, January 21, 2013 - Page updated at 07:30 p.m.

Lake Union’s boom sets high bar for planes

By Bob Young
Seattle Times staff reporter

Seaplane pilots have climbed above, steered away from, and dropped down over it all in South Lake Union, from the chaotic Duck Dodge sailing race to the construction cranes that have come to define the neighborhood’s skyline.

Mayor Mike McGinn wants to add a new challenge: three 24-story condo or apartment towers near the lake’s south shore and the seaplanes’ flight path.

Pilots are less worried, though, about the height of the towers than other concerns they expect to come with the city’s plan to draw thousands of new residents to the area.

After agreeing to move the flight path to accommodate the proposed towers, and getting assurances from city planners that new buildings will not creep into their airspace, Kenmore Air — Lake Union’s chief seaplane operator — is convinced taller buildings will not be obstructions.

“Kenmore can operate safely under the proposed South Lake Union build-out as long as we have a protected air corridor,” said John Gowey, Kenmore Air’s operations director.

Added boat traffic and potential noise complaints from new residents are a bigger worry. Lake Union already is congested, at times, with boats. And in nearby Victoria, B.C., noise complaints have called for serious restrictions on seaplane business.

Kenmore executives have recommended remedies they say would keep seaplanes on Lake Union as the area transforms into a more vertical community.

“Tall buildings next to airports are not something you get excited about,” said Todd Banks, Kenmore’s president. “But you recognize growth is going to happen and you have to deal with it.”

Kenmore has used Lake Union as an airport since 1946. It now operates 18 planes that take off as many as 40 times a day on Lake Union, making it the largest seaplane operator in the U.S., according to Gowey. In the winter, many of those flights take off on a path that cuts over the South Lake Union neighborhood.

The much smaller Seattle Seaplane company also uses the Lake Union airport, as do private planes and charter flights from Canada.

Kenmore’s primary concern is increased boat traffic. “We couldn’t land there during the Duck Dodge,” said City Council member Sally Bagshaw, of a Kenmore flight she was on in August. Kenmore has scrapped Lake Union flights during the Duck Dodge on summer Tuesday evenings.

Kenmore has a solution: lights mounted on three buoys that pilots could activate before takeoffs or landings. The lights would warn boaters to stay clear of a central strip, or runway, in the lake. The whole system would cost an estimated $250,000. Gowey said Kenmore hopes to fund the project through a state aviation grant.

When it comes to noise, Kenmore executives are nervous about what they’ve observed in British Columbia.

In Victoria, the James Bay Neighbourhood Association has raised a ruckus about seaplane and helicopter noise and emissions.

“The issue is no longer one of residential buildings being compatible with an airport, but rather, whether an airport is compatible with residential communities…,” said a 2011 report by the neighborhood group.

The report also called for the city to study aircraft pollution, lobby to end charter tourist flights and install permanent noise monitors.

With this backdrop in mind, Kenmore has asked Vulcan, which wants to build the three 24-story towers, to notify new residents that they couldn’t initiate nuisance complaints against seaplanes for legal and normal flights. Kenmore, which only flies between 8 a.m. and 8 p.m. on weekdays, contends such a guarantee must come from property owners, not local officials.

A spokeswoman for Vulcan, Paul Allen’s real-estate firm, said the company is looking into the possibility of such an easement at Kenmore’s request.

Scooting the flight path

While taller buildings are not Kenmore’s chief worry, that doesn’t mean they’re not an issue.

Most flights take off to the north, toward Gas Works Park, where buildings would not be in the way. But when the wind blows from the south — mostly from October to April — planes take off in that direction because the wind gives them lift.

Southern takeoffs occur rarely in summer and about eight times per day in winter, on average, Gowey said. Takeoffs require greater performance from planes than landings, because of climbing and banking.

In the existing flight path, seaplanes taking off to the south fly over the corner of Lake Union Park into a corridor that takes them north of the 605-foot Space Needle and south of Queen Anne Hill.

The existing flight path clips one of the blocks between Mercer and Valley streets, where a Vulcan tower would stand.

Kenmore and state transportation officials raised concerns about proposed towers obstructing airspace. (The Federal Aviation Administration does not regulate local land-use policies.) The city’s draft environmental study warned that planes might be at an elevation of 150 feet as they pass near the Vulcan towers. Planes might be as low as 225 feet as they fly near Aurora Avenue, where proposed zoning also would allow some buildings up to 240 feet, according to the study.

Vulcan then hired a nationally recognized aviation firm, Barnard Dunkelberg, to evaluate the lake’s aircraft and obstacles.

The firm concluded that seaplanes actually were flying higher near the shoreline — at 250 to 500 feet — than initially estimated.

Kenmore’s Gowey agrees with the revision, stressing that elevation depends on a variety of factors, such as aircraft performance, load, weather and point of takeoff.

He said he recently flew a fully-loaded piston-engine plane that was at 350 feet over the lake’s south end. Kenmore’s turbine-engine planes usually reach 500 feet or higher at the same point, he said.

The best solution, according to city planners, would be to move the flight path slightly to the north. That way planes would steer well clear of the proposed towers.

Planners propose two other fixes.

They would keep building heights from penetrating the sloping flight path.

And, every proposed development over 85 feet, north of Mercer Street and west of Fairview Avenue, would need an analysis to show it wouldn’t cause potentially dangerous shifts in wind patterns.

Bagshaw, a licensed pilot, said she’s satisfied by the proposed safeguards. “I really don’t think there’s a problem. The buildings are still far enough from the lake, planes will be at 500 to 700 feet of altitude easily by the time they get to the edge of the lake,” she said.

Landings that approach from the south aren’t as demanding on planes, Gowey said. “They come down easily,” he said.

Even 400-foot towers proposed on Denny Way wouldn’t be a problem. “In some sense, we’ve already faced that with numerous construction cranes in the area,” he said.

Seaplanes can always land farther north on the lake, he added, as there’s a mile between Gas Works and Lake Union parks. But a steep approach underscores the need for lighted buoys warning boaters to stay clear.

“Our city has had a unique ability for people being able to get along and compromise,” said Banks, “and this is another example of that.”

Bob Young: 206-464-2174 or byoung@seattletimes.com.


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