1.7 Night Operations and Civil Twilight

Night Operations and Civil Twilight

Before April 21, 2021, any night flight needed a waiver. The 2021 rule (Section 107.29) now permits night operations without a waiver as long as you meet a lighting requirement and a training requirement. This is a favorite exam topic because it mixes precise time definitions with a lighting number.

Defining Night and Civil Twilight

The terms come from the Air Almanac and are tested verbatim:

Alaska exception: Because of extreme latitude, Section 107.29 defines civil twilight in Alaska using the Air Almanac — essentially the period when the sun is 6 degrees or less below the horizon, since clock-based 30-minute windows break down at high latitudes.

Anti-Collision Lighting (Section 107.29)

To fly during night — and, under Section 107.29(b), also during civil twilight — the aircraft must have anti-collision lighting that is:

• Visible for at least 3 statute miles, and
• Set to a flash rate sufficient to avoid a collision.

The Remote PIC may reduce the intensity of the lighting if operating conditions make that safer (for example, to preserve their own night vision), but may never extinguish the lights during night flight. The drone's own factory navigation LEDs are usually not bright enough — most operators add a dedicated strobe rated to 3+ statute miles.

Training Requirement

Night privileges also require current training:

• Pilots tested after the rule change cover night content in the initial UAG exam.
• Pilots certificated before April 6, 2021 must complete the updated recurrent training (which now includes the night-operations module) before flying at night.

Civil-Twilight vs. Night Comparison

Common trap: Many prep sites wrongly say lighting is only "recommended" during civil twilight. The regulation is explicit — §107.29(b) requires the 3-statute-mile anti-collision lighting during civil twilight, just as §107.29(a)(2) does at night. The only practical difference is that the special night training/knowledge requirement (§107.29(a)(1)) applies to operations conducted during the period of night.

What Does NOT Change at Night

Every standard Subpart B limit still applies after dark: 3 statute miles visibility from the control station, 500 ft below / 2,000 ft horizontal cloud clearance, 400 ft AGL ceiling, 100 mph speed, and full visual line of sight. Controlled-airspace authorization is still required, though LAANC may have reduced hours at some facilities at night.

Practical Night Factors (Scenario Fuel)

Scenario questions lean on human-factors knowledge: the eye needs 20 to 30 minutes to dark-adapt, and a bright tablet screen can wipe out that adaptation; depth perception and orientation degrade; haze or fog shrinks the effective range of a 3-SM-rated strobe; and cold night air reduces battery capacity, so plan a larger reserve.

Worked example: Official sunset is 7:45 PM. Evening civil twilight ends at 8:15 PM. A flight at 8:30 PM is therefore night and requires the 3-statute-mile anti-collision strobe; a flight at 8:00 PM is civil twilight, which also requires the 3-statute-mile strobe under §107.29(b) — the difference is that the night period additionally triggers the special night training requirement of §107.29(a)(1).

Twilight Math, Lighting, and Night Human Factors

Night questions blend a time definition, a lighting number, and human-factors knowledge. Pilots lose points by treating "night" loosely; the FAA uses precise, computable windows.

Computing the Windows

Work outward from the official sunrise and sunset times for your location and date (published in the Air Almanac and most flight apps):

Worked example: Sunrise 6:10 AM, sunset 8:00 PM. Morning civil twilight runs 5:40 to 6:10 AM. Evening civil twilight runs 8:00 to 8:30 PM. Night is 8:30 PM to 5:40 AM. A 9:00 PM flight is night (3-SM lighting required, plus night training); a 5:50 AM flight is morning twilight, which also requires the 3-SM anti-collision lighting under §107.29(b). The exam typically supplies the sunset time and asks for the exact moment night begins — add 30 minutes.

The Lighting Rule, Read Carefully

During night the aircraft needs anti-collision lighting visible for at least 3 statute miles with a flash rate sufficient to avoid a collision. Two sub-points trip people up: the Remote PIC may reduce intensity when conditions make that safer (preserving night vision, for instance) but may never extinguish the lights in flight; and the drone's built-in navigation LEDs usually fall short of 3 statute miles, so a dedicated strobe is typically added.

The same 3-statute-mile anti-collision lighting is also legally required during civil twilight under §107.29(b) — do not fall for the common misconception that twilight lighting is merely "recommended."

What Stays the Same

Darkness changes none of the core limits. You still need 3 statute miles visibility, 500 ft below / 2,000 ft horizontal cloud clearance, the 400 ft AGL ceiling, full visual line of sight, and controlled-airspace authorization (LAANC hours may be reduced at night at some facilities, pushing you toward a manual DroneZone request).

Human Factors and Physiology

Scenario questions lean on night physiology. The eyes need roughly 20 to 30 minutes to dark-adapt, and a single glance at a bright tablet can erase that adaptation — use red or dimmed displays. Off-center (peripheral) viewing detects dim objects better than staring directly, because the night-sensitive rods sit away from the fovea. Hypoxia, fatigue, and certain medications hit harder at night. And autokinesis — a stationary light appearing to move when stared at — can disorient a pilot tracking a distant strobe. Plan for reduced battery capacity in cold night air by padding your reserve.

Trap: A choice may claim you can extinguish the strobe "if no other aircraft are in the area." That is false — anti-collision lighting may be dimmed but never turned off during night flight, regardless of perceived traffic.