Geography Reference
In-Depth Information
226
Chapman had heard about a new turboprop helicopter being developed by Bell that
supposedly could land at thirteen thousand feet. He proposed to NSF that these be used
during the 1961-1962 season to support a wide-ranging topographic survey based out of
McMurdo Station. The foundation agreed, and requested support from the U.S. Army
for the helicopter logistics. Two HU-1B helicopters (the first of the famous Huey line)
were sent directly from the assembly line at Bell to Christchurch, New Zealand, where
they were assembled and test flown, then taken apart, loaded onto C-124 Cargomasters,
and flown to McMurdo Station.
The plan was bold: a series of remote camps supplied by fixed-wing aircraft from
which the helicopters would operate, and two traverses—one south from McMurdo as far
as Beardmore Glacier (Topo South) and one north from McMurdo as far as Cape Adare
(Topo North), establishing ground control over more than eleven hundred miles of the
Transantarctic Mountains. In a single season Chapman's party could conceivably master
the terrain that had challenged an entire generation of heroic-era explorers.
In the first days of the season, the pilots made a series of test flights, shutting down
at increasingly higher elevations on the sides of Mount Erebus and Mount Discovery. At
the summit of Mount Discovery, at an elevation of eighty-eight hundred feet, one of the
Huey's engines overheated and cracked when the pilot attempted to restart it. After in-
stalling a new engine (the only one they had in McMurdo), the pilots and crew succeeded
in getting the helicopter oV the mountain, but this failure resulted in new rules prohibit-
ing the helos from shutting down at elevations above six thousand feet.
The procedure for surveying is to measure the location of a series of points out from
an accurately positioned station. Three readings are necessary: a direction, a vertical angle
or altitude, and a distance. The direction and vertical angle are measured by a theodolite,
mounted with a telescope to see the “signal” the surveyor is targeting. Distance can be
determined by triangulation—that is, by sighting on the same point from two diVerent
surveyed points. Chapman's party, however, used a Tellurometer, an Antarctic first for
that instrument, which sent an electromagnetic signal that was bounced back by a reflec-
tor at the survey point, with the phase of the signal calibrated to distance. The precise
positioning of stations at the start and the end of the traverse was accomplished by find-
ing stars in the daylight sky with a telescope, rather than the more conventional celestial
sightings.
The three engineers worked as two teams, placed by the two helicopters on peaks
typically fifteen to thirty miles apart. Operating solo, the forward engineer would estab-
lish the site for a new station, set a tablet or benchmark in the bedrock (or use a pole if the
site was snow covered), erect a signal composed of two three-foot-square orange cloth
panels on a pole guyed to the ground, and set up and operate the remote Tellurometer
unit. The two rear engineers would measure all the directions and vertical angles with
the theodolite, with one man doing the sightings and the other recording the data. The
rear team would also set up and operate the master Tellurometer unit, and would photo-
identify the occupied station and all intersected peaks. If time permitted, they would
also build a cairn. If a site was above six thousand feet, the helicopter would leave the en-
gineers and fly to a lower elevation, where it would shut down and wait for a flash from
a signal mirror or, if out of sight, would return at an appointed time. Then the forward
