There are several types of lights on airplane wingtips: navigation, strobe and wing.
The strobe lights are flashing white or red lights designed to make the plane more noticeable in the air at night and on the runway when taking off, landing or taxiing.
The strobe lights are usually placed on each wingtip behind the red and green navigation lights. They must protrude out in order for the light they emit to converge in front of the nose of the plane.
If the lights don't protrude from the wingtips but instead are inset in the wing, the plane is required to have a third light on the tail of the airplane or on its vertical fin for the light to cover the required area around the plane. Some planes may have both as a supplement to the wingtip lights.
Some smaller planes may have only one strobe light on the tail and others may have none on the wing tips and one on the fuselage underneath the plane and one on the tail.
The placement is determined based upon the field of coverage it provides from that position. They cannot "impair the flight crewmembers' vision or detract from the conspicuity of the position lights," according to FAA Part 23 Airworthiness Standards.
The anti-collision wingtip lights may be either white or red, according to FAA Part 23. The level of color of the red and white is determined by section 1397 in Part 23.
The anti-collision lights must illuminate 360 degrees around the airplane and at least minus 30 degrees below or plus 30 degrees above the airplane. Directly above or below the airplane, the light must reach minus and plus 75 degrees from the horizontal level of the plane, according to the FAA. This illumination spread is required so the crew may see "the vital areas around the airplane," according to FAA Part 23.
The intensity of the lights must meet or exceed the listed levels in Part 23 based upon the angle they cover.
The lights must not flash less than 40 times per minute and no more than 100 times per minute. The most effective frequency for each plane is based upon the width of the light beam, the number of anti-collision lights, speed of rotation, and how often the system can be seen from a distance for the size and type of plane.
Position lights, the red and green lights on the wingtips used by pilots for navigation purposes, must be wired separately from the anti-collision lights.
Wingtip strobe lights, or anti-collision lights, are required on any aircraft that will be flown at night. The intensity, or candela, of light emitted is determined by the plane's certificate from the FAA. According to Wheelen Aviation, planes that received production certificates between April 1, 1957 and Aug. 10, 1971 must produce a minimum of 100 candela. Planes with an FAA production certificate from Aug. 11, 1971 to July 18,1977 must have anti-collision lights with a minimum candela of 400. Planes with a type certificate after July 18, 1977 must have strobe lights that produce a minimum candela of 400.