In order for the TCAS system to see the aircraft, the aircraft must be within a maximum range of 30 - 80 NM, and within a maximum altitude range of ________ feet.

In order for the TCAS system to see the aircraft, the aircraft must be within a maximum range of 30 - 80 NM, and within a maximum altitude range of ________ feet.

• A. 6,500
• B. 9,900
• C. 12,000
• D. 15,000

Answer: (B)

TCAS detects other aircraft only within a defined three‑dimensional volume: a horizontal range roughly from 30 to 80 nautical miles and a vertical band around the host aircraft’s altitude. The vertical limit is about 9,900 feet, meaning an intruder must lie within roughly ±9,900 feet of your altitude to be seen by TCAS. This keeps detection reliable using the altitude data reported by transponders and prevents clutter from traffic that is much farther above or below. Among the options, 9,900 feet matches this standard vertical detection limit. Choices like 6,500, 12,000, or 15,000 feet are outside this typical band and wouldn’t define the same reliable detection range TCAS uses.

TCAS detects other aircraft only within a defined three‑dimensional volume: a horizontal range roughly from 30 to 80 nautical miles and a vertical band around the host aircraft’s altitude. The vertical limit is about 9,900 feet, meaning an intruder must lie within roughly ±9,900 feet of your altitude to be seen by TCAS. This keeps detection reliable using the altitude data reported by transponders and prevents clutter from traffic that is much farther above or below. Among the options, 9,900 feet matches this standard vertical detection limit. Choices like 6,500, 12,000, or 15,000 feet are outside this typical band and wouldn’t define the same reliable detection range TCAS uses.