Radar Observer · Plotting — TCPA
A target bears steady and its range falls from 8.0 NM to 5.0 NM in 9 minutes. What is the TCPA from the 5.0 NM range?
- A5 minutes
- B9 minutes
- C20 minutes
- D15 minutes✓ Correct
Explanation
Closing rate = 3.0 NM in 9 min = 20 knots. Bearing is steady, so CPA = 0 and TCPA = remaining range ÷ closing rate = 5.0 NM ÷ 20 kt = 0.25 h = 15 minutes.
Authority: Bowditch (Pub. No. 9), Radar Plotting
Practice the full Radar Observer bank
Free spaced-repetition quizzing across 2550 USCG exam questions — it schedules your reviews so the ones you miss come back until they stick.
Related Radar Observer questions
- Plotting — TCPA
A target's range is 6.0 NM and it is closing at a steady 12 knots on a constant bearing. The time to the closest point of approach (TCPA) is:
- Display — Motion
On a relative-motion radar display, your own ship is:
- Collision Avoidance — CPA
The closest point of approach (CPA) of a radar target is:
- Collision Avoidance — TCPA
TCPA on a radar/ARPA readout represents the:
- Controls — EBL
The electronic bearing line (EBL) on a radar is used to:
- Controls — VRM
The variable range marker (VRM) on a radar measures: