There are certain aircraft that are ubiquitous on the Alaska landscape: the Super Cub, Cessna 180 and 207, the Caravan, the Piper Navajo and from de Havilland, the Otter and Beaver. Capable of operating on fixed gear or floats, the de Havilland aircraft are particularly popular among lodge owners and charter operators. There are currently 38 single-engine Otters registered in the state of Alaska, 27 of which have turbo-prop engine conversions.
Following the successful manufacture of the six-seat Beaver beginning in 1948 -- named one of the “Top 10 Canadian engineering achievements of the 20th century” -- de Havilland designed the single-engine Otter in 1951. Able to carry more passengers, up to 10, with a much heavier payload of about 2,400 pounds, the Otter had the same winning combination of short field takeoff and landing capability and utilitarian design that made the Beaver such a hit in the Canadian bush.
In addition to the aircraft’s short field capabilities, the Beaver also incorporates oversized doors allowing for the loading of bulkier cargo items. Further, modification kits may be purchased that make it relatively easy to load snowmachines, four-wheelers and various drilling and mining equipment.
The company ceased production of the Otter in 1967 and soon after joined the Beaver as a mainstay of off-airport operations in Alaska. Many of the Otters underwent engine conversions in recent years, increasing power and performance as turbo-props. This was the case with the Rediske Air N93PC involved in the fatality crash in Soldotna, which had a Garrett TPE33 engine and four-blade propeller.
A quick look at the de Havilland DHC-3 Otter's performance and accident stats in Alaska over the years:
- Otters have been involved in 34 accidents in the past 50 years.
- Seven of those have involved turbine-powered aircraft. (In contrast there have been 200 accidents with the C207.)
- Prior to Sunday's crash, five Otter accidents, regardless of the engine, involved fatalities.
- Of those five fatal accidents, four were due to pilot error.
- Former U.S. Sen. Ted Stevens, R-Alaska, was killed in a de Havilland Otter in 2010; the cause of that accident was inconclusive, according to the NTSB's findings.
- In each fatal accident involving a DHC-3 Otter, mechanical issues with the aircraft were not deemed a factor.
The NTSB has concluded, overwhelmingly, pilot error is the most common cause of all accidents involving DHC-3 Otters. Typically, the errors involve flying into adverse weather or the decisions pilots make when landing floatplane-equipped models.
Wings Airways in Juneau currently operates five turbine Otters for flightseeing purposes. It's a "great" and solid addition to their fleet, said Mike Stedman, a Wings Airways partner.
"We fly them all summer long and are grandfathered in for 10 passengers," he said. "The Otter is a workhorse. The turbines provide great performance. After the engine conversions we were able to reduce our fleet because we could get twice as much flying from the turbines as pistons."
Stedman emphasized the Otter aircraft’s appeal in a "combi configuration," familiar to many Alaskans, which allows passengers and cargo to be hauled simultaneously. "So many people like them because of the performance. You get short field takeoff and landing, the seats fold up to haul passengers and cargo, it’s really a versatile aircraft," Stedman said.
It's a durable Alaska bush plane, too. Wings currently owns and operates Serial Number 7, built in 1953 -- and the first Otter delivered to the Canadian Air Force. It had 7,000 hours of total time when they purchased it a few years ago and now with its turbine conversion is flown as often as the others in their fleet.
Contact Colleen Mondor at colleen(at)alaskadispatch.com