Which message instructs to remove CID 112 for UAL720?

Which message instructs to remove CID 112 for UAL720?

• A. SR UAL720
• B. RS 112
• C. RF 112
• D. RD 112

Answer: (B)

The key idea is recognizing how a removal instruction is conveyed in these message formats. To remove a specific CID, the message must explicitly indicate the action to remove and specify the target CID. The line that says RS 112 does exactly that: RS signals a removal action, and 112 is the CID being targeted, applied to the UAL720 situation. The other lines either reference the aircraft without performing a removal, or pair a different action code with a CID that doesn’t denote removal, so they don’t instruct removing CID 112.

The key idea is recognizing how a removal instruction is conveyed in these message formats. To remove a specific CID, the message must explicitly indicate the action to remove and specify the target CID. The line that says RS 112 does exactly that: RS signals a removal action, and 112 is the CID being targeted, applied to the UAL720 situation. The other lines either reference the aircraft without performing a removal, or pair a different action code with a CID that doesn’t denote removal, so they don’t instruct removing CID 112.