See and be seen; at night, lights are inexpensive protection. They indicate the relative position of other aircraft, as well as their relative movement. If you add widely-spaced recognition lighting to an aircraft, lights that are pulsed, and stroboscopic lights that actually do flash, you’ll be hard to miss. And at night, that’s just what you want. Still, don’t get too confident — aircraft lights can blend in with city lights, or those in the night sky … and not everyone will (though legally they must) have them on. It is always important to keep a sharp eye out for other aircraft.
WHEN IT’S GOOD TO LIGHT UP
General aviation airplanes (and helicopters) are a fairly unpretentious lot when it comes to strutting their stuff, at night. What do we have, for the most part? One landing light, position lights, and perhaps a rotating beacon. By the way, that landing light might not show up until the gear is extended … especially if the light is attached to the nose strut). Similarly, the beacon might not be mounted in an ideal spot atop the vertical stabilizer, where it would be most visible on a crowded ramp.
GRUESOME LESSON FROM THE REAL WORLD
A Cessna 441 pilot taxies into position on runway 30R at an intersection some 2000 feet from the threshold at Lambert-Saint Louis International. No problem, except the Conquest had been cleared to hold on runway 31, the tower expected that he had, and an MD-80 was then cleared to take off on 30R. The airliner had reached 90 knots before the Cessna came into view, and even though the airliner swerved to miss the smaller plane, its right wing didn’t. It took the top half of the fuselage, and that of its two occupants with it. The NTSB couldn’t help but notice that although the Cessna’s taxi light had been on, its position, anti-collision, and rotating beacon were not. Had they been on, the airliner crew would doubtless have had enough advance warning to take evasive action much sooner. Unfortunately, some pilots feel it is appropriate to keep anti-collision lights (strobes) off while taxiing on the ground and off the active runway — specifically so that the strobes do not impair the vision of other pilots. However, it may be better to be temporarily blind than blind-sided. In the worst case, you will impair someone’s night vision, but even then they will be fully aware of exactly where you are.
WHAT LIGHTS, WHERE?
In addition to the red, green, and white position lights (arranged in a way reminiscent of ships at sea with red to port, green to starboard, and white astern), the Federal Aviation Regulations require just one anti-collision light for aircraft plying the night skies. This can be either white or red, and function by means of a rotating beacon, or a flashing strobe. Position lights (on the wing tips for airplanes, typically) can of course provide a means for pilots to determine the relative direction of other aircraft in flight: When you see red and green, the other aircraft would probably be heading towards you; if you saw only red, it is probably moving from your right to your left; and if you see green, left to right. Position lights must currently be visible from directly forward in the horizontal plane to an angle that is 110 degrees from forward, laterally. They must also be seen within a full 180 degrees (above and below) in the vertical. The rear position light must be visible from within 70 degrees to either side horizontally, and 180 degrees in the vertical as well. The anti-collision light must not distract or impair the pilot’s vision (or obscure the position lights), and they must be visible within 75 degrees up or down from the horizontal.
Inside Information: There are also allowed regions of obstructed visibility totaling not more than half a steradian, which is a fancy way of saying about one twenty-fifth of a complete sphere around your aircraft (which in my opinion, ain’t so tiny). For anti-collision lights, the rules also require an effective flash frequency between 40 and 100 per minute (although for overlapping flashes, where there is more than one light, it can be as high as 180 per minute).
OFF AGAIN, ON AGAIN
Strobe lights are fairly easy to replace, which is good, because they have a hard life. Each time it flashes, traces of carbon are deposited on the inside of their tubes, which reduce their brightness over time. (We’re talking something like every 1000 hours here however, not 10.) Aside from the safety advantages, the irony is that these pulsed lighting systems actually save energy. While they never actually turn off–they dim to a low-intensity of about 30%–these systems also extend the life of the bulbs themselves. And talking about maintenance on bulbs, for those airplanes having landing lights on the cowling area, there’s enough engine vibration there to shake the bejabbers out of most filaments; putting them out on the wings makes more sense. Oddly enough, bulbs that are more powerful tend to last longer, because the thicker filaments in the brawnier bulbs are more resistant to breakage. Just don’t install a bulb that has wattage greater than that for which the system can supply, because what will pop won’t be your bulbs, but your circuit breakers (or your wiring, or your switches).
As we know, the FARs cover everything electrical, be it the instruments in your panel, your source of electricity, and even down to spare fuses. Regarding the regulations covering how radiant your presence needs to be, here’s something interesting. Did you know that, for most of us, landing lights aren’t actually required by law? Look in CFR Title 14, Part 91.209 (Aircraft lights). You will see it mentioned in 91.205(c), however. (These are the night VFR instrument and equipment requirements for powered civil aircraft with standard airworthiness certificates, but the landing light is only required for aircraft operated for hire.) Sure, on most runways, there is enough external lighting to get by, but if you’ve ever tried taxiing or landing without one on a dark runway, you’ll see just how un-extraneous they can become.
A Good Idea: Despite such ostensible inconsequence (and 91.209), the FAA has instituted Operation Lights On to help promote the benefits of “seeing and being seen” wherein pilots are encouraged to turn their lights on within 10 miles of any airport, day or night.
An Interesting Factoid: Older airplanes certified before 1963 weren’t even required by FAR 23 to have anti-collision lighting (at least, if they weren’t planning to operate at night). FAR 23.1401 did have some geometric stipulations as mentioned above, although back then, the coverage had to be only 30 degrees above and below the horizontal.
When it comes time to replace the lighting assembly itself, think about upping the ante on visibility when you undertake the renovation. There are original equipment manufacturers of course, but there are also aftermarket suppliers that often offer a better product. Rotating beacons having inherently life-limited electric motors, gear mechanisms, and these things don’t last nearly as long as the strobe or flashing variety. Innovations such as tail floodlights (which do a nice ta-daa! number on corporate logos) have advantages for us little guys, in terms of safer ground operations. Wingtip lights with integrated landing lights are available.
DO NOT FORGET
I don’t intend to let the importance of having attitude instruments aboard go unmentioned, by the way. And lighting the way is fine, but you should also have something inside (a required flashlight, and at least the required instrumentation), allowing you to maintain aircraft control in conditions where your outside references become compromised (like, uh, at night) and not just so you can see what’s out there!
THE BOTTOM LINE: Where aircraft lights are concerned, ostentatious displays do not equate to conspicuous consumption. One good thing about lights, aside from the fact that they go a long way towards furthering the cause of noise abatement, is that no one is going to send you an electric bill.