How many seconds before CAS TOT does a white phosphorus mark impact?

• A. 15 seconds
• B. 30 seconds
• C. 45 seconds
• D. 60 seconds

Answer: (B)

The mark must be on target and visible when the CAS aircraft arrive, so you time the white phosphorus marker to impact about 30 seconds before the CAS time on target. That lead time lets the WP round reach the target, burn and produce a clear marking plume, and still be visible for observers to confirm the target and guide a final call or adjustment. If you mark too close to TOT, the mark may not be visible in time; if you mark much earlier, the mark can fade or shift with wind. Thirty seconds is the standard balance that reliably provides a visible target cue at the moment of attack.