Germany, Luftwaffe. A Fl22322 Altitude Meter For Late-War Fighter Planes, C. 1944

A F22322 altitude meter constructed of black-finished non-magnetic metal. The face of the meter is marked with white ticks and is numbered around from “0.1” to “0.9”, the bottom has an opening which shows different numbers depending on the altitude. The top also has an opening which changes numbers. The centre bears a white arm. The face is covered with a clear plastic. The left side bears a flat metal label with a cut-out “E” and the right side bears a flat metal label with a cut-out “F”. There are four holes distributed equally around the front the the meter and a black dial is located at the bottom. The reverse of the meter has a central metal attachment piece. The top is labeled with “Hohenmesser FL22322”. The left side is marked “Statischer Druck” (Static Pressure). Below the central attachment is marked in white “RCMI 1973.20.1”. Measuring 85 mm (l) x 80 mm (w), extremely fine.

Footnote: The altitude meter measured the altitude of the aircraft by using the surrounding air pressure and was located on the main instrument panel of German aircraft. An altitude meter such as this was found in Me109, Fw190, Me262 and other late-war aircraft. Altitude was measured in kilometers (km) with a vernier dial scale indicating fractions of a kilometer and kilometers registering in the lower window. The two sliding flat metal labels move along the perimeter of the face; the “E” stands for an aeronautical code “QFE” and the “F” stands for an aeronautical code “QFF”. A pilot would set the E label to the desired Decision Altitude and upon descent if the required visual reference was not detected he would have to initiate a missed approach procedure. The “F” label was set to the desired Acceleration Altitude where the pilot would transition the aircraft from the take-off speed to a climb-out speed.