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Rothera to Scar Inlet AMIGOS to Cape Disappointment AMIGOS

November 25, 2012

Terry writes:

After a Mexican Night dinner and party, including dancing until 3:30 am, I somehow made it to the usual weather briefing at 7:45 am. Clear but windy forecast for Scar Inlet, so probably not flying. But the Scar AMIGOS showed diminishing winds all morning, so I received the word from Andy Barker we’d be flying after lunch with pilot Ian Potten, GA Roger Stilwell, with GA Ash Fusiarski serving as co-pilot. We took off at 3:47 p.m. and arrived at Scar Inlet AMIGOS at 5:24 pm. Ian landed somewhat farther from the AMIGOS this time at about 300 meters, so after putting on harnesses, we had a 15-minute hike with Ash checking for crevasses, followed by me, and then Roger pulling a sledge carrying AMIGOS-4, our tools, and a pallet to place under the new battery box.

New battery box on its wooden pallet platform, and suspended by ratchet straps and rope and lashed to the tower.

New battery box on its wooden pallet platform, and suspended by ratchet straps and rope and lashed to the tower.

Once at the tower, Ash and Roger quickly replaced AMIGOS-1 with AMIGOS-4, which I then verified was working properly. Then Roger attacked the snow and ice covering the old battery box while Ash and I used a couple of ratchet straps to suspend the new box above the snow surface. We then excavated a space under the box into which we slid the forklift pallet. In doing so, we uncovered another narrow crevasse just a meter from the new box but running parallel to it. Meanwhile, Roger succeeded in lifting the lid of the old box without damaging it, revealing ice filling the box and encasing its four lead-acid batteries, its charge controller, and a data logger once used to collect a temperature profile down to about ten meters below the snow surface. Roger closed the old box, we lashed the pallet to the tower, closed up AMIGOS-4, and hiked back to the plane and Ian. We then took off for Cape Disappointment at about 7:35 pm.

The old battery box with its opened lid showing it full of ice and fully encasing its contents.

The old battery box with its opened lid showing it full of ice and fully encasing its contents.

A narrow crevasse unconvered by Ash while removing snow from underneath the suspended new battery box.

A narrow crevasse unconvered by Ash while removing snow from underneath the suspended new battery box.

First image taken by newly fixed Scar Inlet AMIGOS4 showing Ash, Terry, and Roger walking back to the Twin Otter to be flown by Ian to Cape Disappointment.

First image taken by newly fixed Scar Inlet AMIGOS4 showing Ash, Terry, and Roger walking back to the Twin Otter to be flown by Ian to Cape Disappointment.

We circled Cape Disappointment a couple of times, and spotted the tower. It clearly had been blown over. Ian found a landing site about a mile or so to the northwest. After the usual skis-down touch-and-go pass, Ian landed us at 7:55 pm. We decided we would attempt a repair, so we loaded most of the equipment and tools we had brought, including a spare 70-pound, 12-volt battery onto three sleds. We still had our harnesses on. Roger and I donned crampons and Ash wore skis. Roger towed the largest of the three sledges which left Ash with a train of the two smaller sledges. We headed off to the toppled tower about an hour after we had landed.

The rock cage at the base of the tower next to the damaged battery box and the top of the upwind rock cage anchor that had been dragged toward the tower.

The rock cage at the base of the tower next to the damaged battery box and the top of the upwind rock cage anchor that had beed dragged toward the tower.

The three foil wrapped cable connectors that had been ripped from the battery box.

The three foil wrapped cable connectors that had been ripped from the battery box.

At first the tower was visible, but it soon dropped below our immediate horizon as we climbed a small hill. Most of our route was over moderately sculpted sastrugi. The tower soon became visible again near the top of the first hill. We then hit a flat spot for a while, but soon started climbing again. The last few hundred meters was over blue ice, so Ash traded his skis for crampons. The sledges were a bit hard to control over the ice, but we eventually made it to the scree patch surrounding the tower about an hour and 10 minutes after we had left the plane. We took a few photos, noting that all three plastic connectors on the battery box (the two solar cable connectors and the AMIGOS power connector) had been damaged when the tower blew over. The upwind wire cage had been ripped open by its guy wire attached to the tower. We measured about 12.5 volts on the batteries, but zero volts on the load output of the charge controller whose top light was solid red. We tried hot-wiring a battery directly to the power input on the AMIGOS enclosure and did succeed in getting the computer to boot up. I was able to reset the date/time using the ethernet interface since I couldn’t get any output from the serial port.

Opposite side of base cage.

Opposite side of base cage.

Downwind side of tower showing apparently undamaged weather sensor, albedometer, cameras, and solar panels.

Downwind side of tower showing apparently undamaged weather sensor, albedometer, cameras, and solar panels.

By now it was near midnight local time and the sun had dipped slightly below the horizon. We decided to disconnect the charge controller and the entire AMIGOS enclosure, which we then loaded onto the sledeges, leaving the 12-volt battery we had brought. On the way back I relieved Ash of the smaller of the two sledges he had towed which simplified the trip across the blue ice. The trip back was down hill a bit, so we made slightly better time. We loaded up the plane, Ian took off at 01:05 am, and we made it back to Rothera at 2:25 am. Several people had to stay on the job until we landed, including Karen, Adam, and Rosie doing communication and weather observations in the tower, with Clem and Brian in the hangar helping us unload our gear and park the Twin Otter. I got to bed at about 3:30 am, roughly five minutes or so earlier than the previous night.

Terry and Ash returning from Cape Disappointment AMIGOS6, which can be seen at the leftmost tip of the outcrop just above Ash.

Terry and Ash returning from Cape Disappointment AMIGOS6, which can be seen at the leftmost tip of the outcrop just above Ash.

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