AOPA Pilot Magazine
October 1997 Volume 40 / Number 10
Measure of Skill Part 10 of 12: Night Fright
The rules you most need to know
Night flying has its rewards. Pilots are treated to a private showing of spectacular electric light shows as cities slide beneath their wings. The air is usually calm, and winds are light at the destination airport, affording an honest shot at a textbook-perfect touchdown. But night flying is also a fragile skill, one that must be renewed if left unused.
The crux of any flight boils down to a single question: How was the landing? Those new to night flying, faced with fewer visual cues, tend to arrive at the runway hot (too fast) and high. Wind drift is more difficult to perceive. Since there are fewer visual cues to gauge the sink rate, the touchdown usually comes as a surprise, causing some pilots to pull back suddenly. The resulting landing is a bouncer, not a skimmer.
Ron Fowler, in his nifty little book Making Perfect Landings, suggests turning onto final at about 400 feet agl. The advantage to this is that you are always starting the approach from the same altitude. You are not distracted by having to climb or descend; you did that on base. If you are about a mile out, the visual approach slope indicator will show you to be on the proper glidepath. Day or night, this is good advice.
But don't descend below pattern altitude prior to reaching the pattern. If the airport is surrounded by hills or mountains, why not remain at cruise altitude and descend over the airport? Rough terrain is usually uninhabited and, therefore, unlit and difficult to see. And if objects come between you and the runway lights during final approach, they are probably branches. Climb! Airports with uneven terrain and obstructions — such as trees — are difficult enough in daylight.
Fowler suggests, as a touchdown target, a point on the runway at about the third set of runway lights. You should cross the threshold at a minimum of 100 feet. No need at night to try to "plant it on the numbers," if there is adequate runway.
The FAA's Flight Training Handbook offers good advice on how to determine the roundout point. Continue at a constant rate of descent "until the landing light reflects on the runway, and tire marks...or runway expansion joints can be seen clearly." Once you have rounded out, Fowler suggests establishing a touchdown attitude "that has the nose just covering the last set of runway lights at the far end."
But what if you approach with too much speed and float half the length of the runway? Fowler suggests having a go-around point in mind to avoid running off the end.
Just what are you supposed to do if the engine quits at night? First of all, you would hope to be over or within gliding distance of an airport. Most computerized flight-planning programs allow you to select a string of airports as your route to your destination and will calculate the headings to each. Gliding distance will be improved, of course, by high cruise altitudes. That reduces the odds of an off-airport landing and simplifies the search, should one be required.
You also want to avoid rough terrain when flying cross-country at night. It is difficult enough to find a smooth place to land in daylight. File a flight plan and use flight following radar services when flying VFR; you'll have a controller to talk to immediately in the event of trouble.
But what if an off-airport landing is inevitable? The FAA's Flight Training Handbook offers the same initial advice given Air Force student pilots: Maintain control of the aircraft. Prevent a stall from occurring. Establish a normal glide and run through the emergency checklist. Turn on the landing lights in time to illuminate the terrain (forget the joke about turning them off again if you don't like what you see) and turn into the wind. What if you have no landing lights or fog obscures the ground? The Handbook suggests holding the aircraft in a level-landing attitude until the ground is contacted.
As in daytime, the chance for an engine failure is extremely low. A more likely problem is the failure of the landing light. On dark nights with poorly lit runways, there will be no visual cues to aid in determining when to round out and flare. Dual instruction will be required to prepare you for such contingencies. Boiled down, the best thing to do is to set the aircraft up for a soft-field landing. That will place the aircraft in a touchdown attitude for contacting the ground. But remember that leaving the power up can consume a lot of runway. Your instructor will show you that distant runway lights can provide information about sink rate, while those closer (watched with peripheral vision) can be used to determine when to flare.
What do you see at night after the nose is raised to the climb attitude? Nothing, especially if the airport is in a relatively uninhabited area. More important, you don't see a horizon. Use whatever visual references are available, but also use the attitude indicator to set climb attitude and keep the wings level. On especially black nights, monitor the vertical speed indicator to avoid accidentally stopping the ascent and leveling off, or even descending.
We're diurnal rather than nocturnal animals, and therein lies the problem. Human eyes perform poorly at night and are easily fooled by illusion as well. Light-sensitive nerves in the back of the eye are divided into rods and cones. Both can adapt to night vision, but rods, used for peripheral vision during day or night, are much more sensitive.
Unfortunately, rods are not in the center of the eye. Consequently, pilots should look slightly off to one side of an object to see it best.
The center portion of the back of the eye is occupied by cones. To remember that, think of the ash cones that form in the center of a volcano right before or just after an eruption. Cones can adapt to night vision, especially when there is moonlight present, and become 100 times more sensitive than in daylight. They require five or 10 minutes to adapt. Rods take 30 minutes to adapt, but become 100,000 times more sensitive than during daylight. On a moonless night, humans are almost entirely dependent on rod nerves for vision.
Obviously, if you look into the headlights of a fuel truck 10 minutes prior to departure, it will take 20 minutes to readapt to night vision.
Visual illusions can occur in a variety of ways. A highway full of cars can be mistaken by the brain for the true horizon. You will have to depend more on aircraft instruments at night. The horizon may blend into the surface of a large body of water, making it impossible to find. Stars may reflect off smooth water, making both the sky and water appear as one big star field.
You can legally maintain proficiency for carrying passengers by making only three takeoffs and landings to a full stop every 90 days. They must be made in the same category and class of aircraft to be used for carrying passengers, and they must take place beginning one hour after sunset and ending one hour before sunrise, as published in the American Air Almanac. You may log night flying time between the end of evening civil twilight and the beginning of morning civil twilight. And when must the navigation lights be on? Actual sunset to actual sunrise.
Other regulations pertaining to night concern Special VFR clearances and fuel requirements. Towers will not grant Special VFR clearances to pilots at night unless they are instrument rated and are flying an aircraft certified for IFR flight. And VFR aircraft must carry a 45-minute fuel reserve at night, rather than following the 30-minute daylight requirement.
The regulations allow you to practice touch-and-goes in Class G airspace at night in what most pilots would consider rather dangerous conditions. You need only one mile of visibility and must remain clear of clouds, but you must also remain within a half-mile of the runway. Go farther than that and the weather minimums change to three statute miles of visibility and the aircraft must remain 500 feet below the clouds, 1,000 feet above, and 2,000 feet horizontally.
Finally, large and turbine-powered aircraft may not fly VFR at night "over the top" of a cloud layer unless the aircraft has the instruments and equipment required for IFR operations.
You wouldn't want to spend 20 minutes homing in on a beacon, only to find out that it is a heliport. To review, lighted land airports have alternating white and green beacons. Operation of the beacon during daytime means that the ground visibility is less than 3 miles and/or the ceiling is less than 1,000 feet. Military airport beacons have two quick white flashes, followed by green. Heliports have green, yellow, and white beacons that pulse faster than beacons used for airports. A lighted water airport has a white and yellow beacon.
Many uncontrolled airports have pilot-controlled lighting. Key the microphone three times for low-intensity, five for medium, and seven times for high-intensity lights. High intensity is intended for daytime use when fog or obscuring precipitation is present, while low intensity is meant to be used at night.
Visual glideslope indicators come in several varieties. The best known is the VASI, or visual approach slope indicator. A VASI can have either two or three rows of lights, called bars. The saying "Red over white, you're all right" best explains the indication for a proper glidepath. The red bar will appear above a white bar. Two white bars mean the aircraft is too high, while two red bars mean the aircraft is low. Three-bar VASIs show two glidepaths, one for small aircraft and another for larger aircraft. For small aircraft, the top two bars should appear red above a white bar when on the proper glidepath. Larger aircraft with cockpits high above the ground see only one red bar above two white bars. Another type of glidepath device consists of a single light that shows pulsating white when above the glidepath, steady white when on the glidepath, and red or pulsating red when low. Finally, some airports have four lights on one bar. You're on the glidepath when you see two red and two white lights. Three or four white lights means you're too high, and three or four reds means the aircraft is too low.
Large airports have stop-bar lights, red lights across the taxiway at the runway-hold position. Controlled stop bars are used with lead-on lights. When the stop bar is turned off, the lead-on bar allows the aircraft to proceed.
What do you do when your airport is tiny, the runway small, and the lights few? Instructor Jane Carpenter of Fort Collins, Colorado, has a few suggestions for students returning at night to her home base in Ft. Collins Downtown Airport, Colorado.
Her home base has a reputation for being difficult to see, with low-intensity lights 50 feet on either side of the centerline of a 40-foot runway. There is a PAPI for runway 29 but it is so blindingly bright that pilots avoid clicking the mic to turn it on.
One general technique for moonless nights, Carpenter said, is to go around intentionally on the first approach, and use that approach to determine the wind (strong inversions are fairly common there). Students are advised to then set up a fairly high approach with enough flaps to tip the landing light downward to pick out the runway centerline and number (slight oscillations with the rudder helps in this regard). They also turn down all cockpit lighting to as dim as practicable, to better see the runway surface and edges (this is also necessary for no-light landings) and the taxiway which, at Fort Collins Downtown, is not lit.
"Most pilots end up high and fast due to the width illusion of the lights, and then will wind up low and slow on approach to a much larger runway (i.e., nearby Fort Collins/Loveland Municipal Airport) — so the psychological priming for a go-around is very important," Carpenter said. "The second time around, the brain has a better handle on the illusions. For these reasons, I try to make a point of going to a variety of runways during night training.
"One final note I tell my students concerns required lights," Carpenter added. "The regs require anti-collision red or white lights (as well as position lights). That means you could have a beacon or strobes. Which would you rather have going into a dark runway on a dark night? The strobes can be very disorienting, especially if they flash on alternating wingtips. Fotunately the regs allow for turning the strobes off if in the best interest of safety."
For more information on keeping current, see the "Measure of Skill" section of the AOPA Pilot. E-mail the author at email@example.com.