Originally Posted by
BEagle
The venerable JPs had a UUPI - an ultrasonic undercarriage position indicator which gave a short burst of beeps when a transmission was made with landing gear down. Inaudible to the pilots, but picked up by ATC - so if no beeps were heard, a 'check gear' call would be made.
The JP also had a small bright white lamp on the nose that flashed continuously when the landing gear was down. Another useful indication to ATC and the caravan controller during night flying.