Tuesday, December 19, 2006

Helicopters

Besides hiking, helicopters are the main way we travel around the Dry Valleys. The US Antarctic Program and the National Science Foundation handle the helicopters as a service for all scientists down here, who pay for the helicopter hours with grant money. There are 4 US helicopters in use: 2 small A-Star models that can accommodate up to 5 passengers (with limited gear), and 2 larger Bell-212 models that can carry 10 passengers or a lot of gear. The Bell-212s have a helitech on board that serves as a co-pilot and helps with on and offloading gear. This is a complicated process because weight distribution has a great effect on the safety of the flight as well as the amount of fuel used. Since our group is small and we generally don’t have to transport a lot of weight in gear, the stream team usually rides in the A-Star models. These helicopters are special because it is just you and the pilot and one person gets to ride in the front passenger seat (where the helitech would normally sit). This is where you get some of the best views of the scenery!

View of the Commonwealth Glacier from an A-Star helicopter's front seat

Before anyone gets to ride in a helicopter, you must go to a class that teaches you how to fasten the complicated seatbelts, how to act/load gear on a helicopter when the rotors are turning, and what to do in case of an emergency. Before you depart McMurdo, a helitech gives another short lecture about how to weigh and label your gear and how to pick a helmet that fits properly. The sound of an operating helicopter (especially a 212) is deafening and helitechs encourage the use of earplugs because it cuts down on the sense of hurriedness that you get when working around helicopters. Good luck trying to sleep in if helicopters are in the area!

Offloading a Bell-212 when the rotors are turning

The helicopter pilots come from all over (the states, England, Bulgaria, etc) and we’ve gotten to know them all. Some have been coming down to fly here for years. There are 6 or 7 of them that rotate doing day flights and evening flights. They are all interested in what we do, and will do their best to help you out by flying over a stream you’re surveying, or trying to land as close as possible to your destination. Mostly they just enjoy flying the helos (as they’re called down here) and if they have extra time you get to play around a bit.

Riding in one of these machines is fascinating. Instead of creating pressure differences to generate uplift like fixed-wing aircraft, the helicopter’s rotors beat the air into submission through much more complicated physics, allowing the pilot to hover. This feature makes it easy to land in tight spots and most importantly allows you to do some neat sightseeing because you can go slow without losing altitude.

The instrument panel in an A-Star


Both the A-Star and Bell-212 helicopters can transport a lot of weight by something called a sling load. This is basically a net attached to a cable that is hooked onto the bottom of the helicopter. Most of our fuel drums get out to camp this way. The loads have to be pretty heavy (at least 700 lbs) or they can bounce up or get blown into the rotors! This was the cause of the most recent (2003) helicopter crash in the Antarctic.

Pilot Marco in an A-Star helicopter delivering a sling load to F6 camp

2 comments:

jianantonic said...

How tall is that glacier? And why are the sides like that? (non-science speak, please)

Your pictures are incredible. More blogging, more pictures, and more cowbell, please.

Emily said...

Distances and heights are difficult for me to gauge out here...but the glacier dude says that the sides of the Commonwealth are probably about 30 meters high.

The sides are cliffs because of calving (ice chunks breaking off). Because the sun is so low in the sky, the vertical surfaces of ice recieve more heat and melting than do the horizontal surfaces. This causes weakening of the sides and subsequential calving. That's the basic explanation but I'm sure there's more to it than that.