Flight Command Indicator ID-524/ARR-39A for SAGE System
The ID-524 Flight Command Indicator was a panel mounted component of the AN/ARR-39A Fire Control Data Link System, connecting to the ground-breaking system known as SAGE - Semi-Automated Ground Environment. The AN/ARR-39A system was installed in F-86D's Sabrejet Fighters along with an extensive electronics package in the late 1950's, becoming the F-86L Sabre Interceptor aircraft of the US Air Force.
SAGE, an innovation developed by MIT, was the US's first air defense system (extensive history can be found here). A cross-linked network of radar and communication, the system could vector interceptor aircraft to an inbound threat in real time.
The SAGE system was later interfaced with versions of the F-89 Scorpion, F-94 Starfire, F-102 Delta Dart and F-106 Delta Dagger. However, we've only found evidence documenting this particular indicator as being used in the F-86L.
This indicator, with a 1957 date stamp and a blue Confidential tag attached, displays altitude (COM ALT) and air speed (COM SPEED KNOTS). We have not found documentation of its use, and our educated guess is that this is the altitude of the threat and its air speed relative to the interceptor. The air speed index rests at center "0", and travels up (INCR) or down (DECR) by 240 knots. Altitude indicates up to 60,000 ft. There is a small window on the altitude side just below "1000", its function is unknown.
This example is new old stock, in its original packaging. Measures 3.25 inches diameter and ~6 inches deep.