Seaplanes are a Seattle icon. Their pilots are mystified by a tragic crash.

Last Sunday’s fatal crash of a seaplane off Whidbey Island stunned and mystified the region’s aviation community, for whom sturdy de Havilland floatplanes have been a routine yet thrilling part of life here.

Seaplanes have been part of Seattle’s fabric since Boeing’s first plane took off from Lake Union in 1916. Today they provide regular commuter and tour service throughout the Pacific Northwest from Seattle to the San Juan Islands, Alaska and British Columbia.

The trajectory of Sunday’s flight — a normal takeoff and climb with no significant weather and about 18 minutes of routine flying before a sudden, steep plunge into the sea without a distress call — is, for now, unexplained and deeply disturbing.

Colleen Mondor, an author who specializes in investigating air accidents in Alaska involving similar aircraft, said this flight pattern before such a disastrous end is very strange.

“That sure sounds like a stall,” Mondor said. “It’s weird to be 18 minutes into a flight and all of a sudden to exhibit that kind of behavior with the aircraft.”

The plane was a de Havilland Canada DHC-3 Otter turboprop operated by Renton-based Friday Harbor Seaplanes.

Though this aircraft type has suffered a rash of accidents in Alaska over seven decades of service, those have almost exclusively been tied to poor pilot decisions in rough terrain and bad weather. The aircraft is considered safe.

“They’re older. But they’re really good airplanes,” Mondor said. “They’ve flown for a long time for good reason. They don’t fall out of the sky.”

Jay Todhunter, chief pilot with Kenmore Air, which runs a much bigger floatplane operation than Friday Harbor Seaplanes, described the Otter as “a great airplane to fly.”

“We all love it. It’s perfect for what we use it for. It’s a fairly tame airplane, for the most part easy to fly,” he said.

Todhunter said pilots at the two companies know each other. He had occasionally shared casual conversations on the dock at Friday Harbor with Jason Winters, the pilot on Sunday’s fatal flight.

“There’s kind of a community within the pilot group here,” Todhunter said. “It’s a tragedy and it’s in all of our thoughts right now.”

An icon of Pacific Northwest aviation

Seattle seaplane flights typically delight first-time flyers as they look with fresh eyes from the air at the region’s breathtaking scenery of mountains, lakes and ocean.

Kenmore Air flies out of both Lake Union and a seaplane base at Kenmore on the north end of Lake Washington. Vancouver, B.C.-based Harbor Air and charter company Seattle Seaplanes also fly in and out of Lake Union, while Friday Harbor Seaplanes operates out of a base at the southern tip of Lake Washington in Renton.

These commuter and tourist seaplanes are permitted to fly only in daytime, clear weather conditions. They cannot take off unless the cloud ceiling is above 1,000 feet with visibility of at least two miles ahead. Fog means canceled flights. Winter flying is limited.

The most popular destinations include Friday Harbor, Orcas Island, Victoria, Vancouver and Desolation Sound in the northern reach of the Georgia Strait.

Many of the flyers are island residents commuting to Seattle and destinations beyond.

In addition, air charter company Seattle Scenics offers seaplane tour flights from Lake Washington at Renton and Kirkland. And there are thousands of takeoffs and landings performed by private noncommercial floatplanes in this region each month.

It’s not all tourists and commuters on these flights. The floatplanes ferry professionals of every description to and from the islands, including whale biologists, doctors, architects, attorneys, boat technicians and IT specialists.

The planes routinely transport perishable food to island restaurants and, when the ferries are down, essential supplies.

The more than 100-year history of floatplanes here has a grip on those in the business. Once flying catches the imagination, it tends to be passed along through generations.

Todd Banks, president of Kenmore Air, has been in the aviation business 31 years. His grandfather, Bob Munro, started operating seaplanes on Lake Washington and Lake Union in 1946.

“Seaplanes are vital part of the transportation system in the Northwest ... to access some of the most beautiful places in the world,” said Banks. “It’s been a privilege to be part of it.”

The DHC-3 Otter, seating 10 passengers, is an aging workhorse of this system. It was first built in the 1950s and a total of 466 were produced through 1967. Almost all those flying today have been updated from piston to more powerful turbine engines.

The Otter is a familiar sight even to Seattleites who’ve never flown in it. Kenmore uses it, along with a smaller six-passenger model called the DHC-2 Beaver, on the scenic flights that take off from Lake Union and top the downtown skyscrapers as they fly out.

Weighing in just below the 12,500 pound threshold above which regulations require a crew of two in the cockpit, it’s one of the largest airplanes that can be flown by a single pilot.

The Federal Aviation Administration aircraft registry shows Northwest Seaplanes, the parent company of Friday Harbor Seaplanes, with just a single DHC-3 Otter in its fleet — the one that crashed — along with four DHC-2 Beavers.

Kenmore Air has a current floatplane fleet of 10 Otters and seven Beavers.

The air navigation site used by pilots shows an average of 119 seaplane landings or takeoffs per day from Kenmore’s Lake Union base and 118 per day at its Lake Washington base in 2019. About a fifth of those are private seaplane operations without commercial passengers.

The same site shows the Lake Washington seaplane base at Renton used by Friday Harbor Seaplanes averaged 46 takeoffs or landings per week in 2020, a down year due to the pandemic.

Bulk of previous accidents occurred in wilderness

The Otter’s ability to take off in a short stretch and climb fast, which makes it ideal for Lake Union, also means it’s “one of the finest bush planes ever built,” said David Gudgel, Kenmore’s chief operating officer, referring to planes that can land and take off in the wilderness of Alaska.

There, the plane is used by multiple small operators for adventurous operations that have accounted for the bulk of Otter accidents.

“They’re landing in rivers and lakes and flying through mountains,” said Gudgel. “A lot of those (crashes) I think you’ll find are pilot error.”

The Geneva-based Bureau of Aircraft Accidents Archives compiled a comprehensive database stretching back 54 years to 1963 that shows 52 fatal DHC-3 Otter crashes, including Sunday’s.

Of those, 21 were military aircraft. The U.S. Army lost a few in Vietnam. Another eight were wheeled versions for land use or equipped with skis for snow landings. Of the 23 fatal civil floatplane accidents listed, 19 were in North America and caused 70 deaths.

The cause in many cases was attributed to the pilot making a choice to fly in bad weather. A few other accidents were caused by the pilot failing to balance the load in the cargo bay before takeoff, shifting the plane’s center of gravity.

Mondor said the vast majority of these Alaska backcountry accidents have been “very specific to pilot decision-making concerning load or weather decisions and not about the airplane.”

These accidents occurred in an environment much more hostile than the scheduled and charter commuter services operated out of Seattle.

“We don’t deal with the terrain and the weather that they deal with up there. It’s a lot different,” said Kenmore’s Todhunter.

The Swiss database shows no previous accidents for Friday Harbor Seaplanes or its parent company, Northwest Seaplanes.

Kenmore has suffered one fatal crash, in October 1977, when seven people died flying over Stevens Pass in a DHC-2 Beaver. The investigation report found the pilot hadn’t balanced the aircraft’s load and made “improper in-flight decisions,” flying too low.

In the ensuing 45 years, Kenmore has had no fatalities.

The analysis of previous DHC-3 Otter accidents leaves Sunday’s crash mystifying.

The flight path was straightforward. The pilot was experienced.

Though it was a little windy, there was nothing troubling in the weather.

Chuck Perry, who has been a pilot for more than 36 years and was Kenmore’s chief pilot before Todhunter, said the Otter is a heavy, stable airplane in high wind.

The plane was full Sunday, but if the load had been unbalanced that should have been clear on takeoff.

In addition to examining the wreckage once it is retrieved, investigators will look at the plane’s maintenance records, searching for any possible mechanical anomaly.

Northwest Seaplanes deferred questions to National Transportation Safety Board investigators.

A stressful time

The entire aviation community has been through a financial crisis that forced layoffs during the pandemic-driven air travel downturn. That has stressed airplane operations everywhere, from Boeing to major airlines to aircraft repair and overhaul shops.

Bureau of Transportation Statistics, which provides data on scheduled passenger services, though not similar figures for charter flights, shows that Friday Harbor Seaplanes carried nearly 3,400 passengers in pre-COVID 2019 but just half that number in 2020.

However the business rebounded in 2021, with more than 5,500 passengers carried.

Kenmore’s Banks said that in this “very small, niche part of aviation” he knows fairly well Shane Carlson, who runs Northwest Seaplanes, founded by his dad, Clyde Carlson.

“They do a good job,” Banks said of his smaller competitor.

He texted Shane on Sunday after the accident to express condolences.

“It’s a tragedy,” Banks said. “It’s just a hard time for us right now.”

Banks said he understands if people are now afraid to fly on a seaplane. This week, one customer canceled a charter flight with Kenmore.

“We are more than happy to give people refunds, or whatever they want to do, if they’re feeling anxious about it,” Banks said.

Todhunter, who spoke Tuesday before he took off on a sightseeing flight, said he remains “very confident in what we do.”

“I don’t know what happened in this accident, I don’t know why it happened,” he said. “But I feel very good about the way we do things. We like to play it safe.”

Perry, his predecessor as chief pilot, said, “I just really hope that they can get that airplane out of the water, because it’ll tell the story.”

“That’s going to be all-important to figuring out what happened,” he said.