Playing in the dark

Dateline: Northamptonshire, England, April 28, 1910. “Today daring aviator Claude Grahame-White, desperate to beat competitor Louis Paulhan to Manchester to claim the Daily Mail’s £10,000 prize, became the first man in history to take off in an aeroplane at night and fly in the dark. Lifting off at 2:50 a.m. by the headlamps of his party’s automobiles and navigating by the lights of railway stations, Grahame-White....”

Made history to no avail. He failed to catch up to Paulhan, losing a purse that in today’s money would be worth a cool million dollars. But bold or reckless—or both—the first night flight was no small feat. Grahame-White’s 50-horsepower Farman III biplane was more frame than wing and had no electrical system or lights and no instruments of any kind.

But if a million bucks isn’t on the line, why fly at night? Lots of reasons: Airplanes perform better in the cooler night air; the atmosphere is generally more stable and less turbulent; and the airspace is less crowded. Plus night flight stretches our capabilities, requires special skills, develops confidence, and is insanely beautiful.

However, playing in the dark requires different awareness, mindset, technique, gear set, and knowledge of unique regulatory requirements.

You and the night. Unlike leopards, bats, owls, badgers, cockroaches, and the Panamanian night monkey—humans are not nocturnal. We don’t see as far at night, and we have a harder time judging distance and discerning fine detail.

In fact, part of the human eye can’t see at night at all. The “night blind spot” is a five- to 10-degree diameter circle at the center of your field of vision that doesn’t function in low ambient light. At night it’s possible to not see an object you are staring at directly. Actually, our peripheral vision is superior for night vision—the exact opposite of daytime, when our best vision is dead center and our peripheral vision is our poorest. Additionally, the human eyes take 30 to 45 minutes to fully adapt to darkness after having been in brightly lit areas.

And if that’s not enough, night vision gets worse with increasing altitude, and it doesn’t take much. The FAA advises the use of supplemental oxygen at altitudes above 5,000 feet during night flight to prevent vision deterioration.

Of course it’s not just our eyes we need to look to for night flight; our bodies and brains are designed to sleep when it’s dark. This, combined with our poor night vision, contributes to one of the greatest dangers of night flight: optical illusions. Our minds get tricked and don’t properly process what we are seeing. Optical illusions can lead to either spatial disorientation or landing errors.

Overcoming biology. To overcome the eye’s slow adaptation to dim light, upon completion of preflight—which requires bright light—night pilots should shut off hangar lights if possible, and dim cabin and instrument lights to the minimum during taxi and runup. Turn down your iPad’s brightness setting to the lowest level, and do the same for any glass panel avionics.

In flight, if brighter white light is needed—for instance, checking a chart—keeping one eye closed while the brighter light is on will help maintain your night vision. You can compensate for your night blind spot by doing constant visual scans during night flight, and a study of common nocturnal optical illusions will help you recognize one if you encounter it.

Lastly, because our bodies are programmed to sleep once it’s dark, it’s important that you’re well rested for night flight. Consider an afternoon nap prior to a night flight and avoid a large dinner, which can make you drowsy.

Your airplane and the night. According to federal aviation regulation 91.205, in addition to the standard equipment required for day visual flight rules operations, for night VFR flight an aircraft must have position lights, anti-collision lights, a landing light if operated for hire, a power system to run all of this, and a spare set of fuses if your aircraft uses fuses instead of circuit breakers. That’s it.

Beyond the required equipment for night flight, FAR 91.151(a)(2) stipulates different minimum fuel requirements for night VFR. You must carry an extra 15 minutes of reserve fuel—enough to reach your destination plus 45 minutes at normal cruise burn. That’s the regs. Most experienced night pilots carry significantly more fuel for safety, and you should, too.

Lastly, FAR 91.155 raises the Class G airspace night minimums from one mile visibility to three miles, except within a half-mile of a runway. The cloud clearance remains the same.

And although not required by the regs, night flyers should also carry not one but two flashlights with them, and one of the lights should have a red “night vision” filter. Make sure your batteries are fresh and have a good charge.

Is it night yet? So, how is night defined by the FAA? Well, it depends on where in the regs you look. As laid out in FAR 1.1, for the purposes of logging night flight for a private or commercial certificate, night is the period of time between evening civil twilight and morning civil twilight. Civil twilight, in turn, is the moment when the geometric center of the sun is six degrees below the horizon.

Seriously? Yes. But don’t worry about it; you can look up civil twilight times for more than 22,000 cities and towns online at the U.S. Naval Observatory’s Astronomical Applications Department (http://aa.usno.navy.mil/index.php).

For night currency to carry passengers: FAR 61.57(b) defines night as one hour after sunset to one hour before sunrise, and requires three take offs and full-stop landings—not touch and goes—in the same category and class (and type, if required) airplane that you will be carrying passengers in, within the previous 90 days.

But the FAA isn’t finished defining night for the purposes of aerial navigation just yet. Those lights your airplane needs? Which night do you turn them on for? None of the above. Your position and anticollision lights, per FAR 91.209, need to be on at sunset, and stay on until sunrise.

Lighting the night. Airports are marked by rotating beacons that can be seen as alternating flashes of white and green light from many miles away. If you see a beacon that’s white-white-green, it’s a military field, the owners of which mostly likely won’t take kindly to your dropping in for a friendly visit.

At nontowered airports, and after-hours at towered airports, the facility’s lighting systems can be activated from the air using your com radio on a designated frequency (usually the common traffic advisory frequency or tower). Key the mike seven times in five seconds to turn on the field’s runway and taxiway lights to their brightest, five times for medium intensity, and three times for the lowest setting. It’s actually kind of fun watching all the lights come alive.

The lights will stay on for 15 minutes, so if your approach is slow, you might want to key the mic again on downwind to avoid the stomach-wrenching experience of having the airport “black out” on short final.

Flying through the night. Flying at night requires an adjustment to both your altitude and your attitude. For altitude, look to your charts and make sure that you are flying high enough to clear any terrain or obstacle, both on your flight path and in the general vicinity of your flight path. Sometimes we don’t navigate as precisely as we’d like, and just because you can’t see the ground doesn’t mean you can’t hit it. At night, higher is safer.

For attitude, it’s not your airplane’s attitude that matters as much as the one between your ears. Pay greater attention to your weather briefing. Night weather is often tamer, but harder to see. You can’t stay clear of clouds if you can’t see them. If the weather is questionable on your intended route, a flight that you might safely navigate in daytime could prove difficult after sunset. A greater degree of go/no-go discipline is required for safe VFR night flight.

Emergencies at night. Surely there’s nothing worse than sudden silence in a dark airplane on a moonless night. You can work an electrical failure with your pair of flashlights, but an engine failure requires a landing within gliding distance (another reason to consider carrying some extra altitude at night).

Selecting a good off-field spot for an emergency landing at night is challenging at best, but the key is the same as it is for a day emergency landing: Keep your head and fly the airplane all the way to the ground. A controlled landing is always more survivable than a stall or stall-spin.

Up with the bats and the owls. Unlike Grahame-White, we no longer need the headlamps of our friends to light our fields; we have all manner of lights to assist us. We have a few night-specific regs for gear, fuel, currency, and visibility. We need to be aware of how our eyes work at night. And we need to be rested and we need to plan carefully, but the night awaits.

And while it’s not likely that flying at night will win you a million bucks, flying at night can sure make you feel like a million bucks.