Twin Otter flights to Lettau AWS and Tom AWS

It’s been another busy week as we visited more AWS. On Wednesday 22 January and Thursday 23 January Lee and I flew by Twin Otter fixed wing aicraft to Lettau AWS, on Wednesday, and Tom AWS, on Thursday. Wednesday was my first flight on a Twin Otter, so I was eager to get flying. But, of course, it’s not as simple as hopping on the plane and leaving.

There is more time and preparation that goes into flying by Otter than by helo. All the cargo, aside from the literal passengers and some small bags, needs to be entered into the cargo system. Then, as opposed to departing right from McMurdo as you do with helo, the Otter departs from Pegasus airfield. The cargo needs to be ready out there when we want to fly, so we need to enter it into the system at least 2 days before we fly. We find out if we’re on the schedule to fly the night before flight date. Around 7 am the following morning we get a call from fixed wing ops whether we are a go or we have been canceled. If we’re a go, we need to catch the shuttle out to Pegasus, which leaves McMurdo at 8 am. The time between the call and the shuttle can get hectic. That shuttle ride is about an hour, and it takes about an hour to prepare the Otter for flying (loading cargo, fueling up, etc). And finally, inherent in Otter flights is that the travel time to AWS is almost always longer than helo because we only use the Otter for AWS that are too far away for the helo to reach. I’ve now discovered that all these factors add up to very long work days when flying by Otter.

Lee and the Otter, preparing to depart Pegasus

The flight to Lettau took 2 and a half hours. It’s a great time for reading, taking a nap, or enjoying the sights.

Length aside, it’s always great to get to AWS, especially when we get one working again like we did at Lettau. Our goal was just what we accomplished: install the enclosure and get the station transmitting again via Argos. All the instrumentation was already on the tower. The only additional thing we needed to do was raise the lower temperature sensor about a foot. There isn’t usually much accumulation there, so that usually makes servicing easier.

Arrival at Lettau AWS

Me, securing the enclosure

Lettau AWS upon completion

On Thursday, we flew to Tom AWS. We had ambitious goals for this day; we wanted to remove Tom and reinstall it at a location nearby, but far enough away to measure data unique to the original location of Tom. This flight took just over 3 hours, and considering how long it usually takes to remove and install an AWS, our plans had us pushing right up against the Otter pilots’ duty days (the number of hours they can work in a day; I think it’s around 14 hours).

We arrived to Tom AWS at 1 pm and got to work right away. This was a full removal, so we needed to dig out the tower section, batteries, and the dead men attached to the guy wires.

Arrival at Tom AWS

There was more accumulation and many more layers of ice than we anticipated, so the removal took too long. It was the only thing we could do that day. We also had to cut our time there short because we needed to stop at a fuel cache along the way back to McMurdo to refuel. All four of us, myself, Lee and the two pilots, ended up digging the station out. Each of the holes (4 total) ended up being about 5 feet deep. One consolation to the rapid and tiring work was that we successfully removed it all.

Proof of the successful removal

It was time to head back to McMurdo, first stopping at CTAM (the Transantarctic Mountains Field Camp) to refuel. The scenery was stunning. We flew along and over the mountains for the hour-long flight to CTAM.