When a collocated VOR/DME has the VOR portion inoperative, the DME identifier will repeat at what interval?

When a collocated VOR/DME has the VOR portion inoperative, the DME identifier will repeat at what interval?

• A. 60 second intervals at 1350 Hz.
• B. 30 second intervals at 1350 Hz.
• C. 20 second intervals at 1020 Hz.
• D. 30 second intervals at 1020 Hz.

Answer: (B)

The key idea is how the DME keeps identifying itself when the VOR part isn’t working. In a collocated VOR/DME, each navigation aid has its own identification signal. If the VOR portion is out, only the DME identifier remains active. The DME transmits its Morse ID on a 1350 Hz tone, and that ID repeats every 30 seconds. This cadence keeps pilots aware of which DME is being received, even with the VOR out, and the 1350 Hz tone helps distinguish the DME ID from the VOR ID (the VOR ID uses the 1020 Hz tone). So the DME identifier repeats at 30-second intervals on 1350 Hz.

The key idea is how the DME keeps identifying itself when the VOR part isn’t working. In a collocated VOR/DME, each navigation aid has its own identification signal. If the VOR portion is out, only the DME identifier remains active. The DME transmits its Morse ID on a 1350 Hz tone, and that ID repeats every 30 seconds. This cadence keeps pilots aware of which DME is being received, even with the VOR out, and the 1350 Hz tone helps distinguish the DME ID from the VOR ID (the VOR ID uses the 1020 Hz tone). So the DME identifier repeats at 30-second intervals on 1350 Hz.