DME Nolockon RNAV

When in search mode, the aircraft is transmitting at 150 pulses pairs per second (PPS). When it is locked on, it is transmitting at 24 PPS. If the aircraft were to continually transmit at 150PPS, there is the chance it could contribute to the DMEDME —Distance Measuring Equipment becoming saturated because it cannot deal with all of the aircraft interrogating it. Consequently, there is a built in drop to 60 PPS after 15000 pulses have been sent. This helps to stop the ground equipment from becoming saturated.