Bombardiers' Information File US Army Air Force May 1945 Viscount It has also been identified

It has also been identified visually in cockpit illustrations in the flight manuals of the patrol aircraft PBY-5 Catalina and the dive bomber SB2C Helldiver

The manual is full of detailed information on all of the systems of the aircraft

This particular protractor has a tag from the US Naval Observatory stamped 1945

altimeter in that it has one pointer (sensitive altimeters have 2-3 pointers)

so likely for a US Navy aircraft

Bombardiers' Information File US Army Air Force May 1945 Viscount It has also been identifiedHere is a WWII era Bombardiers' Information File published by the US Army Air Force May 1945. It contains the essential information on the duties and responsibilities of the bombardier. It is in exceptional condition given its age. Measures 8. 5 x 11 inches, and ~0. 5 inches thick.