If a callsign is not answering you, try to reach them for a total of three times with several seconds passing in between. Each additional time they may add the information that they haven’t received anything, to make other stations aware of it.
If the suspected station is your superior you may assume that they may be incapacitated and/or killed and the next station in the Chain of Command needs to take command in their place.
Example
This example will cover a squad net on channel 250 consisting of Outlaw 1-0, 1-1, 1-2 and 1-3. 1-2 is trying to reach 1-0 without success:
Trying to contact
1-2: Actual, this is 2.
1-0: (1-0 is not responding so after a couple of seconds 1-2 tries again)
1-2: Actual, this is 2, nothing heard.
1-0: (1-0 is not responding so after a couple of seconds 1-2 tries for the last time)
1-2: Actual, this is 2, nothing heard OUT.
1-0: (1-0 is not responding so 1-1 needs to take command)
Succession of command
1-2: 1, this is 2.
1-1: 2 this is 1.
1-2: You need to take command.
1-1: This is 1, taking command..