Thomas L. (Tommy) Thurlow worked with the Fairchild Aviation Corporation to
develop a small and rugged aircraft sextant suitable for military use. The basic
form received Army designation as the A-10 in 1941. It has a plunger that the
navigator could push when making a shot, that would make a mark on a white
plastic disc. After taking several shots in quick succession, the navigator
would remove the disc and determine their median value.
This example (an A-10-A) was made in 1944 by the Fairchild Camera and Instrument Corporation, as the firm was then known. It has an electrically
operated timer such that observation marks were made once a second as long as the navigator held the trigger down. The Air Force was still using instruments
of this sort in the late 1950s.
Thurlow was a creative, tenacious, and fearless Army aviator. Soon after his death in an air accident in 1944, Sherman Fairchild established the Thurlow
Award for contributions to the science of navigation. This award is given by the
American Institute of Navigation.
Ref: Handbook of Instructions with Parts Catalog. Type A-10 Aircraft
Sextant (June 10, 1943; revised April 25, 1944).
U.S. Air Force, Air Navigation (Washington, D.C., 1954, reprinted
1957), pp. 322-325.
P. V. H. Weems, Air Navigation (New York, 1958), pp. 279-283.