The de Havilland Canada DHC-6 Twin Otter is a Canadian engineering marvel, capable of landing on practically any surface: water, snow, ice and rocky terrain. Runways are entirely optional.
In the 1970s and early 90s, I was fortunate to fly with many different Twin Otters and operators on combinations of straight skis, wheel skis, mixed nose ski and wheels, high flotation tires, and floats. Using these aircraft to support our research took me all over the vast landscape of the Canadian Arctic, ranging from Tuktoyaktuk in the Beaufort Sea to the High Arctic Islands and east to the Canada/Greenland border in Baffin Bay.
This work often involved taking everything needed to set up winter tent camps and live out on the floating ice for weeks to months at a time. Temperatures below -30°F were commonplace and one memorable unloading took place out on the ice at -67°C (without the wind chill!) with the engines kept running so the oil wouldn’t congeal instantly. As the charterer, I often managed to claim the right seat, whereupon the pilot on hearing that I had my PPL, promptly handed over the controls and took a snooze. The fact that my experience was with a fabric-covered, 85-hp taildragger seemed to matter not a bit.
A number of experiences from this time flying in some of the remotest and most hostile parts of the planet are indelibly imprinted on my memory bank. Hopefully, my look back at a few of these, focused the iconic Twin Otter will prove entertaining.
In 1974 we were carrying out an experimental oil spill in a small cove called Balaena Bay, south of the Distant Early Warning (DEW) Line station at Cape Parry on the Beaufort Sea coast in the Northwest Territories. Normally, we conducted resupply flights out of Inuvik with the Twin Otter landing on a tiny frozen lake near the camp. Now it was well into June and the ice was rotting and unsafe.
I was instructed by my boss to “create” a sort of runway on a hummocky patch of tundra with boulders sticking out all over, so that 18 VIPs could visit for a show and tell. Nobody paid any attention to my protestations that this was crazy and far too risky. Several days of digging out as many of the bigger boulders as possible provided a patch about 50 ft in width and less than 1,000 feet long. To call it a runway was laughable, and I reluctantly announced its completion with a sense of impending disaster. Large embedded rocks still stuck up a foot or more along the “strip.”
My only consolation was a belief in the basic sense of self-preservation acquired by all good bush pilots. I remained convinced the pilot would do a low pass and then go home with all the innocent souls still safe onboard. To my horror, he came around again and made a full flap STOL approach, hanging on the stall. I closed my eyes and opened them to see the Twin Otter literally bouncing over the rocks on its high flotation tires, with the two PT6s roaring in full reverse. Somehow, he pulled off the landing. This was a good thing as any overrun would have destroyed the aircraft.
The takeoff was even more interesting. I was highly motivated to go along as this was my only ticket to civilization (six weeks in remote isolation really ramps up your internal risk meter). The Twin Otter became airborne at the last second and then dipped down into a shallow valley in ground effect before climbing out. That was the last runway building exercise I ever agreed to.
Skis down but no snow
In 1980 I experienced the toughest project of my life, camped out on 15 ft thick floating ice 650 miles from the North Pole at 79°N, and drilling holes to drop sonar and profile the keels of old ice pressure ridges extending up to 120 feet underwater. We had a Bell 206 with us to haul gear around and depended for supply runs on a Twin Otter out of Resolute Bay, the nearest speck of civilization 300 miles south of us. In this case we had the camp all packed up and were anxious (read desperate) to get home. The photo at right shows the Twin Otter arriving as our ticket to paradise (i.e. any point south of where we were).
The pilot at the time was held in the highest regard, with tens of thousands of hours of experience—in other words, bush pilot royalty! That day, he had been flying umpteen hours and was way past currently-accepted duty cycle limits. On final approach into Resolute, I could easily see the red ski light illuminated on the panel from my seat in the forward most row. Instead of speaking up, I let the approach continue, assuming that the experts up front must know something that I don’t.
Needless to say, the deceleration on the bare gravel runway with skis down was something to behold. We must have stopped in a hundred feet! Nobody said anything but I’m sure the maintenance crew charged with maintaining the very expensive retractable wheel skis might have had a few choice words. My lesson #1 was to always speak out in a cockpit setting if something doesn’t feel right! #2 was to pay serious attention to the effects of fatigue on my own flying!
Hard (very hard) Landing
Another experience in the early 1980s proved once again that Arctic flying in extremely remote areas came with real risks and that the Twin Otter could handle situations that would destroy many other aircraft. We had waited days in the tiny Inuit hamlet of Spence Bay (now known as Taloyoak) for the weather to clear enough for us for us to work out on the ice. Finally, the ceiling lifted enough for us to fly out over the nearby ice pack to investigate an area rich with very old (five years or more) ice floes. The landing on a smooth patch surrounded by the undulating, much rougher ice of interest was uneventful but still somewhat risky as we didn’t have the benefit of being able to check the thickness ahead of time. We relied entirely on the pilot’s “gut instinct” that the ice would support the aircraft.
The return flight at the end of a long, cold day was anything but normal. Fog had rolled in and entirely obscured the airport and the community right down to the ground. There was no possibility of making a visual approach under the cloud deck, and the presence of low hills nearby squashed any thoughts of a blind letdown—this was 15 years before GPS. The nearest alternate was hundreds of miles away and out of reach with the fuel remaining. With no dewpoint spread and the temperature dropping, waiting for the fog to clear was not an option.
While orbiting on top over the airport, the pilot caught a fleeting glimpse of the runway through a hole in the fog layer. He immediately spiraled down and literally dropped the aircraft onto the runway from an indeterminate height. This was definitely not a stabilized approach or even a “landing” in sense that there was no approach, round out or flare. It all happened in a blur.
I was sure that with the force we hit, there was no way the wings were still attached. Amazingly, the plane appeared to be intact. In absorbing the impact, the undercarriage and wheel skis were slammed up with such force that all the restraining wires connecting the skis up to the wing attachment points were snapped. It was the end of our project and we boarded the Northwest Territorial DC-3 sched home the next day with a huge feeling of relief at having dodged a bullet. The Twin Otter was ferried back to its base in Resolute for what I hoped was a very thorough inspection.
While most of our experiences landing on floating ice involved retractable wheel skis, one operator developed the technique of landing on ice using oversize tundra tires. We would survey the ice pack around the camp by helicopter and select a suitable area with a sufficient run of smooth ice. Preferred sites were refrozen leads where a natural opening between rougher floes earlier in the winter exposed the water to rapid freezing. The resulting young ice sheet was usually quite smooth, with a thin windblown snow cover.
As a final check we would drill in several locations to confirm approximately 20 inches of cold, hard ice with no ponding or slush. Hovering off to one side in the Bell 206 while the Twin Otter “dragged” our selected landing spot provided a birds-eye view of the approach. The pilot would establish a very gradual descent and allow the big tires to just kiss the snow surface, progressively allowing more weight to bear until the pilot was satisfied in the runout. On a clear blue-sky day in March, the landing was a thing of beauty to watch, with a plume of fine powder snow left hanging in the air as evidence of another safe arrival.