Navigation Lights Information

Navigation lightNavigation lights are white or colored illumination devices used on aircraft, watercraft, and spacecraft. They provide visual signaling and awareness of position, status, and heading between craft and vessels, which is especially important during nighttime vehicle operation. Navigation lights also indicate craft position or movement to personnel on land, such as an aircraft controller, ground crew, bridge engineer, harbormaster, marina yard manager, marina yard crew, longshoremen (e.g., stevedore, dockworker), or port terminal operators. Navigation lights are also known as running lights, marine lanterns, signaling lights, or, colloquially, nav lights.

Headlights or spotlights provide illumination and visibility to the operator of the craft or vehicle and are not considered a type of navigation light. Aids to navigation, such as buoys, channel markers, or lighthouses, often utilize light to guide mariners, but are also not considered navigation lights. Aids to navigation help mariners navigate channels safely while avoiding shoals, submerged rocks, or other navigational hazards. Runway lights or aircraft warning lights are not considered navigation lights. Runway lights guide an aircraft onto the runway. Aircraft warning lights are attached to towers, tall buildings, chimneys or stacks, cranes, electrical transmission pylons, and wind turbines.

Navigation lights can utilize a variety of technologies, such as light emitting diodes (LEDs), incandescent or filament, high intensity discharge (HID), flashing or strobe lighting, and halogen lighting, to provide color or white lighting.

Lenses, control panels, and ingress protection are additional factors to consider when selecting navigation lights. The lens and body should protect the lamp, electronics, and electrical power components from rain, snow, seawater, and dust damage as well as from severe temperatures. Lenses should allow the navigation light to be viewed throughout the required angle. A proper navigation lighting control panel should be selected to maintain control and monitor a craft’s nav lights. In the event of a light failure or open circuit, the controller should trigger an audible or visible alarm to notify the crew. The navigation lighting system should also have a back-up or reserve power supply to keep the craft visible in the event of a main power supply system failure.

The bodies or housings of navigational lights are typically manufactured from corrosion resistant materials such as aluminum, brass, bronze or copper alloys, stainless steels, and composites or plastics. The lenses are manufactured from glass or transparent plastics. The materials of construction and seals between components should be able to resist climate and environmental contaminants.

Types

Nautical navigation lights: In U.S. waters, navigation lighting requirements for boats and marine vessels are prescribed by the U.S. Coast Guard in their Navigation Rules Part C – Lights and Shapes (Rules 20 to 31) or USCG Nav Rules PDF. As a military branch, the U.S. Coast Guard is part of the U.S. Department of Homeland Security. Other countries will have specific navigation light rules, which apply when a vessel enters foreign territorial waters. In addition, international rules apply in international waters. The rules define required colors, shapes, and location of the navigation lights dependent on the vessel length and type (e.g., sail, power boat, large ship, fishing vessel, barge). The pattern of lights visible to a mariner can tell the mariner the orientation and direction of the observed vessel, which allows the mariner to make course corrections to avoid collision, when necessary (see The Bosun’s Mate Navigation Lights).

The rules for small boats and recreational marine navigational lights are straightforward, requiring simple configurations. Red, white, and green colors indicate the position or direction of the craft or vehicle. For instance, if a boat has red and green lights, then the bow or front of the boat is facing the observer. A small anchored boat should have a single white anchor light mounted on a mast that is visible from any direction (360° all-around). The green position light or sector lantern is located on the starboard (right) side with visibility from clear ahead of the bow to an angle of 112.5° along the starboard side. A red position sidelight or sector lantern is located on the port (left) side with visibility from clear ahead of the bow to an angle of 112.5° along the port side. Small marine craft should also have a white stern light at the back end or stern of the vessel and an elevated masthead light. On some small craft, the red and green sector lights can be combined in a single lantern mounted on the bow. Some sailboats can use a composed lantern consisting of white, red, and green lights mounted on the top of the mast.

Navigation light regulations

The rules for large vessels and specialized commercial marine vessels can require navigation lights with more complex configurations with visibility extended to several miles (e.g., Positioning of Lights Vessels 50M in Length and Above). Dredging vessels, piloting vessels, fishing vessels, trawling vessels, submarines, diving support vessels, towed vessels, towing vessels, seaplanes, and vessels restricted in their ability to maneuver all have different navigation lighting configuration requirements. A vessel “restricted in her ability to maneuver” is a vessel (often a work boat or ship) where the ability to deviate from her course is restricted due the nature of the work, such as laying, servicing, or picking up a navigational mark, submarine cable, or pipeline; dredging, surveying, or underwater operations; transferring persons, provisions, or cargo while underway; launching or recovery of aircraft; mine clearance operations; and towing. Very high tonnage and large ships may have limited maneuverability and should be given a wide berth by smaller boats. 

Towing lights that magnetically attach to a steel hull are often used when a vessel or barge is towed. Towing lights are typically yellow, and dredges must also mark the dredge line with lights. Fishing craft may use drift lights to mark the positions of fish gillnet and lobster traps. Moored and towed barges present a serious danger because these unpiloted vessels cannot change position on their own and personnel are not on board to radio an oncoming vessel or blast a warning horn signal. The U.S. Coast Guard released a safety alert on barge fleet lighting because, “Within the U.S. Coast Guard Eighth District alone, marine  casualty  data  indicates  that  over  the  past  12  years,  44  recreational  vessels  have  struck  (allided)  moored  barges within barge fleets, resulting in 26 fatalities and 44 injuries.” Unmanned barges should have, “an unobstructed white light of sufficient intensity to be visible for at least 1 nautical mile.” Blue and red flashing lights are restricted for use on police and rescue watercraft. Amber lights are used in some specialized marine craft applications. The distance a light should be visible to an onlooking mariner is described in Rule 22 Visibility of Lights (see below). On larger marine craft, the masthead light should be visible to a mariner six miles away from the vessel. A masthead light for a larger vessel is a white light placed over the fore and aft centerline of the vessel, which shows an unbroken light from clear ahead to 22.5° abaft the beam on either side of the vessel.

In addition to navigation lights, boats and ships also have several illumination lighting systems and hundreds or thousands of on deck and below deck light fixtures. None of these are navigational lights.

Navigation Rules Part C—Lights and Shapes (Rules 20 to 31)
Rule 20—Application
Rule 21—Definitions
Rule 22—Visibility of Lights

The lights prescribed in Rules 20-31 shall have an intensity as specified in [Section 8 of] Annex I to these Rules so as to be visible at the following minimum ranges:
(a) In vessels of 50 meters or more in length:

(i) a masthead light, 6 miles;
(ii) a sidelight, 3 miles;
(iii) a towing light, 3 miles;
(iv) a white, red, green, or yellow all-round light, 3 miles.
[(v) a special flashing light, 2 miles.]

(b) In vessels of 12 meters or more in length but less than 50 meters in length;

(i) a masthead light, 5 miles; except when the length of the vessel is less than 20 meters, 3 miles;
(ii) a sidelight, 2 miles;
(iii) a sternlight, 2 miles;
(iv) a towing light, 2 miles;
(v) a white, red, green, or yellow all-round light, 2 miles.
[(vi) a special flashing light, 2 miles.]

(c) In vessels of less than 12 meters in length:

(i) a masthead light, 2 miles;
(ii) a sidelight, 1 mile;
(iii) a towing light, 2 miles;
(iv) a white, red, green, or yellow all-round light, 2 miles.
[(v) a special flashing light, 2 miles.]

(d) In inconspicuous, partly submerged vessels or objects being towed;

(i) a white all-round light; 3 miles.

Rule 23—Power-driven Vessels Underway
Rule 24—Towing and Pushing
Rule 25—Sailing Vessels Underway and Vessels Under Oars
Rule 26—Fishing Vessels
Rule 27—Vessels Not Under Command or Restricted in Their Ability to Maneuver
Rule 28—Vessels Constrained by Their Draft
Rule 29—Pilot Vessels
Rule 30—Anchored Vessels and Vessels Aground
Rule 31—Seaplanes 

Aircraft navigation lights: Aircraft have many different types of lights used during the operation of the craft. 

Navigation light

  • Navigation lights or nav lights are similar to marine navigation lights. Aviation nav light indicates the orientation of the aircraft relative to the observer. The green position light is located on the starboard side with visibility from the front dead center to an angle of 110° back along the starboard side. A red position light is located on the port side with visibility from the front dead center to an angle of 110° back along the port side. Aircraft also have white strobe lights at the tips of the both wings (wing tip tail lights). Larger aircraft may have additional strobe lights on the trailing edge to make the aircraft more visible. Aircraft have a white light on the tail or stern of the aircraft with a 140° angle of visibility.
  • Beacon/anti-collision lights are red flashing lights to indicate the engines are powered and the aircraft is traveling or will be traveling down the runway soon. Aircraft have two beacon lights; one on the top center and one on the bottom center of the aircraft.
  • Taxi or nose lights are bright white lights located on the front landing gear strut. They make the aircraft more conspicuous during taxi, takeoff, or landing.

Aircraft also have the following lights or lighting systems for illumination: wing lights to illuminate the wings and engines; outboard landing lights, inboard landing lights, and runway turnoff lights to provide illumination in front of the aircraft so the pilot and crew can see where they are going; and logo lights to illuminate the airline’s logo on the horizontal stabilizer.

UAVs, drones, RC model aircraft: According to FAA regulations, the “appropriate anti-collision lighting” is required on UAVs. UAVs should be operated during daylight hours and civil twilight hours (30 minutes before dawn, 30 minutes after dusk).  Additional recommendations on drone navigation or running lights are available from various trade or professional organizations such as Air Medical Operators Association, AirTractor, Professional Helicopter Pilots Association, and CropLife America. Small UAVS, drones, or model radio controlled aircraft can be very small and hard to see. The hovering ability of some of the craft can further impair detection. Many organizations recommend strobe or flashing LED lights or a lighting system intense enough to enhance a UAV’s visibility to other UAV operators as well as to larger commercial aircraft during daylight conditions. According to the FAA regulation, “Operation and Certification of Small Unmanned Aircraft Systems," the FAA currently has no data indicating what color(s), if any, would enhance the conspicuity of small unmanned aircraft.  Unlike boats, ships, or large aircraft, many of the UAVs, such as quadcopters, do not have a bow (front) or stern (back) and they can move in any direction. The craft are so small and “there is not a clearly defined relative position on the aircraft, so navigation lights would not be practical."

Automotive/motor vehicle lighting: While headlights would not be considered navigation lights, they do usually indicate the front of an oncoming motor vehicle. The main function of some of the lights on motor vehicles is identification or signaling, so they could be grouped with navigation lights.

  • Turn signal lights could be considered a type of navigation light because they indicate position or intended direction of the vehicle.
  • Brake lights indicate that a vehicle is stopping or has stopped.
  • Emergency flashing lights indicate a problem with the vehicle or occupants.
  • Parking lights, front position lamps, or front sidelights indicate the orientation of a parked or standing vehicle at night.
  • Rear position lamps, tail lamps, or tail lights are typically red and indicate the rear of the vehicle.

Bicycle lighting: Bicycles are usually fitted with lights and/or reflectors to increase their visibility to motor vehicles and other bicyclists. A front white or yellow light and a rear red light or reflectors are common requirements or regulations in many locations. Country or state authorities usually define the specific regulations.

Railcar/mass transit lighting: Railcars have traffic or turn signal, brake, rail or tail lights, and strobe lights and flashing hazard lights.

Resources

Tranberg—Technical Papers Lighting

Sentinel Press—Colregs: Navigation Lights: International Rules

International Maritime Organization (IMO)—International Regulations for Preventing Collisions at Sea 1972 (Colregs)

Federal Aviation Administration—Recent Regulations and Guidelines

Aerospaceweb.org—Aircraft Lights and Beacons

Image credit:

Dave Bezaire and Susie Havens Bezaire / CC BY-SA 2.0



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