Position lights, also known as navigation lights, include a green light on the right wing, a red light on the left wing and a white light on the tail of the airplane. These lights work together to illuminate an airplane during nighttime operations, indicating to pilots in the vicinity not only the location of the lighted airplane but its relative direction of flight. Pilots can identify whether an airplane is flying toward or away from them at night based on these lights.
Per CFR Part 91.209, position lights are required during night operations - from sunset to sunrise.
Anti-collision light systems include the aircraft’s beacon and/or strobe lights. Some aircraft have both a beacon and a strobe light system, and other airplanes just have one or the other.
Per CFR Part 91.209, an aircraft that has an anti-collision light system installed must not operate without the anti-collision lights on, unless the pilots deems it necessary to turn off the anti-collision lights in the interest of safety (while taxiing on the ramp, for example, a pilot might wish to taxi with the aircraft’s strobe lights off so as not to impair the vision of other pilots or ground personnel).
And this is where the issue of aircraft lights often becomes unclear. Many pilots operate with the strobe lights and the beacon on all the time because they interpret the FAR to mean that they must. Other pilots interpret the regulation to mean that as long as at least one of the anti-collision lights - either the beacon or the strobe lights - is on, then they’re operating within the guidelines of the regulation. Who is right? Either one, or both. A pilot should operate with the anti-collision light system on unless he deems that, in the interest of safety, a portion of the anti-collision light system should be turned off to prevent vertigo or spatial disorientation, or as a courtesy to other pilots in the vicinity. This means that while it is not necessarily illegal to operate with just the beacon on, it is prudent to use the entire system when able. For this reason, you’ll see that the common practice is to turn on the beacon before startup and to turn on the strobes right before takeoff, as a courtesy to others in the ramp area.
The use of landing and/or taxi lights, installed on most airplanes, is optional. If operating an aircraft for hire at night, a landing light is required to be installed on the airplane, but there is no regulation that states that the landing light must be on or illuminated in order to operate an aircraft at night. If a pilot thinks that a landing light is necessary, either to illuminate the runway environment or for collision avoidance, he should use it. If not, he can leave it off.
AIM Guidance and Operation Lights On
In addition to the existing regulations, the FAA has implemented a program called “Operation Lights On,” which encourages pilots to use lights for collision avoidance and offers the following guidance (AIM, 4-3-23).
“Prior to commencing taxi, it is recommended to turn on navigation, position, anti-collision, and logo lights (if equipped). To signal intent to other pilots, consider turning on the taxi light when the aircraft is moving or intending to move on the ground, and turning it off when stopped or yielding to other ground traffic. Strobe lights should not be illuminated during taxi if they will adversely affect the vision of other pilots or ground personnel.”