25 septembre 2020 |
Local,
Aérospatial,
Sécurité
Chris Thatcher
In early June, the RCAF regained possession of a CC-138 Twin Otter that, 15 months earlier, had suffered severe damage to its nose and tail during a difficult landing on the ice of the Beaufort Sea
A workhorse of the north, the Viking Air DHC-6 was built to withstand much that the harsh Arctic could throw at it. But this aircraft's return to service is a tale of ingenuity and a testament to the recovery and salvage capability of the Air Force and its partnership with Canadian industry.
The aircraft, 803, was one of two Twin Otters from 440 Transport Squadron in Yellowknife participating in Operation Nanook 2019, an annual Canadian Armed Forces interoperability exercise with allies and civilian agencies held across the Arctic.
The crew was on a scouting mission near Pelly Island on that afternoon of March 10, 2019, carrying three defence scientists looking for landing spots on the unprepared sea ice to conduct research later in the exercise.
They had landed without incident near Tuktoyaktuk earlier in the day and were attempting to set down on a smooth area of ice when the aircraft “bounced into the air after contacting a drift perpendicular to the aircraft's heading ... [and] impacted the base of a larger drift,” according to the flight safety investigation report, collapsing the nose landing gear.
One hundred and sixty kilometres away in Inuvik, Maj Andrew Oakes, commander of the second Twin Otter, had just settled into his hotel room when the phone rang. “I thought to myself, this is not good. There is only one person I know with a sat phone at the moment who could be calling my cell phone.”
The news was mixed: There were no injuries but there was no way the crew was flying the aircraft off the ice.
Armed with their location, Oakes and a crew immediately took off in the second CC-138 “to see if we could land and pick them up.” When he arrived overhead an hour and a half later, the damaged Twin Otter was sitting low in the ice and the nose, buried in the snow, appeared to be sheered off. With the low angle of the sun, the undulations of snowdrifts were now visible across the ice. He quickly reconsidered attempting a landing.
Landing on ice requires a deft touch. Because of its varied operations, the CC-138 has a landing assembly that includes both tires and skis, a heavier and less flexible construction than just the skis. The aircraft must set down at the exact spot “you want to land” and then slow as rapidly as possible, using reverse thrust and some elevator control. “It is tricky. It is easily the most challenging thing that is done in a Twin Otter,” said Oakes.
While the stranded crew had prepared a snow camp for the night, a civilian search and rescue helicopter, dispatched from Inuvik shortly after the accident, soon arrived on scene and transported them back to the town.
An instructor on the Twin Otter, Oakes had been seconded to the exercise as an aircraft commander from his job as a staff officer for air mobility readiness at 1 Canadian Air Division (1 CAD) in Winnipeg, Man. He soon found himself tasked with commanding Operation Recovery, an air task force quickly assembled to salvage the aircraft.
The RCAF has over many years developed considerable specialized recovery and salvage capability. And in 2012, a CC-138 with a sheared nose landing gear strut was lifted from dry tundra southwest of Inuvik in much warmer conditions. More recently, in -20 C temperatures of January 2019, the RCAF employed a CH-147F Chinook to lift and sling a CH-146 Griffon belonging to 417 Combat Support Squadron some 50 miles from the Cold Lake Air Weapons Range after the helicopter's main rotor blade struck a communication tower. MGen Christian Drouin, commander of 1 CAD at the time, observed: “We now have this recovery capability because of the professionalism and ingenuity of the personnel involved.”
The preferred and most cost-effective option would have been to fly in technicians from 440 Squadron and the salvage and recovery team based at 8 Wing Trenton, Ont., to repair the aircraft on the ice and fly out. “It would have been very good exposure for the technicians, because it is not something they would do normally. They have equipment and some training on how to extract an aircraft from [unusual] sites,” said Oakes.
However, daytime temperatures were already reaching -5 C and forecasted to rise to zero, so conditions to land and take off from ice on skis were no longer ideal. “When you are warmer than minus 10, landing and takeoff distances will start increasing exponentially.”
He also weighed a second option of calling in a Chinook from 450 Tactical Helicopter Squadron in Petawawa, Ont., to lift and transport the Twin Otter back to Inuvik. But nighttime temperatures were “still going down quite a bit and there was a chance the aircraft would freeze in .... That would be a worst-case scenario where no one is getting the aircraft off the ice, period.”
In the end, the discussion among the crews and with 1 CAD was “pretty short,” Oakes recalled. In coordination with the Combined Aerospace Operations Centre in Winnipeg, a plan was soon in place to lift and sling the aircraft with contracted support from Momentum Decisive Solutions.
By March 16, a CC-177 Globemaster III carrying two Griffon helicopters and various technicians from 440 Squadron and the salvage team arrived in Inuvik. Under the watchful eye of a Canadian Ranger patrol from Tuktoyaktuk that arrived by snowmobile and set up predator defence from polar bears that had been spotted in the area, the technicians began to lighten the CC-138 for airlift. They removed the nose gear, fuel and non-essential parts, and then strapped wooden blocks to the top of the wings to sling the load. They also attached a drogue parachute to help stabilize the flight.
On March 24, Oakes watched from one of the Griffons as a Sikorsky S-61R, a derivative of the S-61/SH Sea King, operated by VIH Aviation Group of British Columbia, lifted the 7,800-pound CC-138 and, steadied by the chute, began the 160-kilometre flight to the Inuvik airport. To manage the distance, VIH had prepositioned a fuel cache on the ice about midway from Inuvik. Even without its own power, the Twin Otter still wanted to “fly,” Oakes observed. “It was pretty spectacular to watch.”
A brand-new aircraft
Bringing the Twin Otter back to life was no small task. KF Aerospace, formerly Kelowna Flightcraft, is the prime contractor for a CC-138 life extension project as well as regular in-service support. Within days of the incident, the company was contacted and dispatched aircraft maintenance engineers to Inuvik to guide the removal of the wings. Back in Kelowna, they then built special fittings to anchor the aircraft in the cargo hold of a CC-177.
When the damaged Twin Otter arrived at their facility on June 14, special jigs and a donor nose were already in place. “This isn't the first time we've had to fix the nose section of a Twin Otter, so we had some good jig structures ... and we were able to reuse them,” explained Gregg Evjen, vice-president of maintenance and engineering.
KF Aerospace frequently performs heavy structural modifications, including freighter and tanker conversions, so the tricky modifications to the CC-138 were well “within our wheel house,” said Evjen. Still, the company had to fabricate some parts to connect the new nose and repair the landing gear and tail section.
With the aircraft already stripped bare, the company took advantage of the situation to conduct a full periodic inspection and maintenance program and complete the life-extension package, including re-winging the airframe. “It looks like a brand-new airplane,” he said.
KF Aerospace has taken on some challenging jobs in the past, including an upgrade program for the Bolivian Air Force T-33 jet that involved taking apart and crating aircraft, flying them to Canada for the modifications, test flying them, and then re-crating and returning them to Bolivia to be assembled. Resuscitating a Twin Otter was hardly new. “But the fact that it was up North and had to be brought off the ice pack, and we had to mount it in a C-17 and manufacture special fittings so we could strap it down properly – that was unique,” said Evjen.
Though the military strives to be self-sufficient and will build capacity to overcome most obstacles, Operation Recovery was a textbook example of the collaborative role civilian partners can play.
To Oakes' surprise, it was also a remarkable instance of how quickly the chain of command can make decisions when time is of the essence.
“I was really impressed with the speed that this came together, and with the level of co-ordination and teamwork,” he said. “It was a great example of how we can get things done. It did help working with the civilian contractor. They were experts. They knew exactly what to do and they had the equipment.”
https://www.skiesmag.com/features/operation-recovery-airlifting-cc-138-off-arctic-ice/
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