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Classifying a flight after civil twilight ends

Remote Pilot (Part 107) practice question 24 of 34 on Regulations / Operating Rules. ACS element UA.I.B.K25 · difficulty: applied. Want to answer it in a timed quiz? Use the Remote Pilot (Part 107) practice mode.

Question bank updated 2026-09-22

QUESTIONOfficial sunset at an operating location outside Alaska is 7:10 p.m. Under the civil twilight definition in § 107.29, a small UAS flight that begins at 7:55 p.m. is

  1. Aa civil twilight operation, because civil twilight begins at sunset and lasts for one hour
  2. Ba daylight operation, because part 107 treats the first hour after sunset as daytime
  3. Ca night operation, because evening civil twilight ended at 7:40 p.m.
Show the answer and explanation

Correct answer: C. a night operation, because evening civil twilight ended at 7:40 p.m.

  • A — incorrect Evening civil twilight lasts 30 minutes after official sunset, not one hour. By 7:55 p.m. the twilight period has ended.
  • B — incorrect Part 107 has no such rule. Daylight ends at official sunset, civil twilight runs for the next 30 minutes, and night follows.
  • C — correct § 107.29(c)(2) defines evening civil twilight outside Alaska as the period from official sunset to 30 minutes after sunset. 7:10 + 30 minutes = 7:40 p.m., so a flight at 7:55 p.m. is at night and must meet § 107.29(a).

BACKGROUND

Section 107.29 governs operation at night and during civil twilight. Outside Alaska, § 107.29(c) defines civil twilight as the 30 minutes before official sunrise and the 30 minutes after official sunset; in Alaska it is the period defined in the Air Almanac. During civil twilight, the small unmanned aircraft must have lighted anti-collision lighting visible for at least 3 statute miles with a flash rate sufficient to avoid a collision. At night the same lighting is required, and in addition the remote pilot in command must have completed an initial knowledge test or training under § 107.65 after April 6, 2021. The remote PIC may reduce the intensity of the anti-collision lighting for safety but may not extinguish it. With sunset at 7:10 p.m., civil twilight ends at 7:40 p.m., so a 7:55 p.m. flight is a night operation.

STUDY TIP

Add 30 minutes to official sunset (or subtract 30 from sunrise) to find the civil twilight boundary, then decide which set of § 107.29 requirements applies.

KEY POINTS

  • Evening civil twilight outside Alaska: official sunset to 30 minutes after sunset.
  • After that boundary the flight is a night operation under § 107.29(a).
  • Night requires 3-statute-mile anti-collision lighting plus post-April 6, 2021 knowledge test or training.

SOURCES

  • 14 CFR 107.29(c)(2)
  • 14 CFR 107.29(a)
  • 14 CFR 107.29(b)
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SkyDrill is not affiliated with the FAA. This is an original practice item based on 14 CFR part 107, 14 CFR part 89, and the FAA Remote Pilot – Small UAS Study Guide (FAA-G-8082-22). Regulations and handbooks are revised; confirm details against the current edition.