September 22, 2008
The airplane may not know it's dark, but the pilot does, and the accident record shows it. AVweb's Thomas P. Turner helps reduce the risk of night flight.
Countering the argument that "The airplane doesn't know if it's light or dark," the record clearly shows a greater number of aircraft accidents at night. The AOPA Air Safety Foundation's Nall Report of general aviation accident statistics shows the increased hazard of flying at night. According to the 2007 edition of the report, "... only 19.2 percent of daytime accidents resulted in fatalities, but over one-third (34.6 percent) of all night accidents were fatal ... At night, nearly half of the accidents in VMC conditions were fatal ... compared to nearly three-fourths of night IMC accidents." There's a lot of added risk to flying in the dark. How can we minimize that risk?
Bad Is Worse At Night
At night, what might otherwise be inconveniences can become life-threatening emergencies. If confession is good for the soul, then my spirit will get a double-dose of medicine this month. Both experiences I am about to relate occurred at night, very early in my flying career, and in retrospect were incredibly stupid.
Stupid Pilot Trick #1
My mechanic had just signed off the annual on my 1946 Cessna 120. I had hoped to get the entire inspection on this simple airplane done in a day, but as a backup, I had arranged to stay at a friend's home if we didn't finish up. (I was a roughly two-hour flight from home.) I'd even given myself a deadline: If the airplane wasn't buttoned up and ready to go by 4 p.m., I'd call my friend and have him pick me up.
The inspector had found a little surface corrosion on an aileron fitting, and I had a little trouble reinstalling it (under the mechanic's supervision) after sandblasting and painting. That ate into my "launch" time, and it was about 4:45 p.m. before everything was closed up signed off. Thinking I could still beat the darkest night home (it was October), and with verified reports of very clear VMC for hundreds of miles around, I cast off my earlier plan, threw my overnight bag behind the antique Cessna's seat and turned on the master switch ... but didn't have the power to crank the engine.
I rationalized that I must've shorted the battery when I removed it to clean the battery box during annual, so I did what any good taildragger pilot would do: I got my mechanic to sit in the copilot's seat while I hand-propped the little Continental engine, then jumped in and bid him farewell. A few minutes after 5 p.m. (more than an hour after my "no-go" time), I took off and headed west. Already the first auto and house lights were glowing in the autumn dusk.
My battery seemed to charge all right, but an hour and a half later I was over very dark prairie east of Wichita when all my lights failed. I was alone, in the dark, with only a flashlight to show the way. I passed just south of a well-lighted runway, knowing my home 'drome sported 24-hour runway lighting. I already had the intense gas flame of a refinery near my destination in sight, so navigating in the clear, dark skies was easy. Only when I lined up with my home runway did I realize I didn't have a landing light, and in a three-point landing stance I would loose sight of anything straight ahead. Somehow my wheels kissed the pavement; I taxied clear and shut down. Only when I climbed out and stood on the tarmac did it occur to me how incredibly stupid most of my decisions had been that night, and how much my choices sounded like the write-up from a fatal NTSB report.
Stupid Pilot Trick #2
A year or so later I was tasked to fly a Beech Baron from its base in northern Kansas down to Wichita. I hitched a ride up with a coworker in a Piper Warrior and, after inspecting the Baron and its logbooks, waved him homeward. We'd had stronger-than-expected headwinds on the way up, delaying my departure just enough so it would get dark before I got back home. I fired up the piston twin and took off, VFR, southward -- the first time I'd every flown that particular Baron.
About half an hour out of Wichita, I noticed a ground fog developing. ATIS at Wichita Mid-Continent reported IFR conditions but well above minimums, so I called Center and picked up an IFR clearance in the air (ah, the Midwest). About the time I was on a vector to intercept the localizer for the ILS, as it was getting dark enough, I turned on the instrument panel lights. Nothing happened. It's hard to check panel lights for operation in daylight, but what I later learned was a faulty rheostat prevented them from coming on when I needed them. I'd not gone out of my way to shade the instruments and check that panel lights worked before I took off, knowing I'd be flying at night. What followed was the classic "flashlight in the mouth" approach set-up and landing, at least until I was low enough on the approach that the runway lights shone through the fog.
There are a lot of "I should've done this" or "I should not have done that" in both these stories, lessons I've absorbed and integrated since that time. I'm sure in reading my confessions you've thought of some of the same things. But re-living these two potential disasters, and reviewing dozens of nighttime NTSB reports, I've come up with some techniques for minimizing the risk for night flight.
Night Safety Do's And Don'ts
- Fly at night without a thorough weather and NOTAMs briefing -- no exceptions. Beware of reports of marginal VFR, converging temperature/dewpoint spreads, temperature inversions or reports of winds blowing off large bodies of water: all can lead to rapidly deteriorating ceilings or visibilities you can't detect visually before you're in them.
- Make a night flight right after airplane maintenance or an annual inspection. A post-maintenance flight should be a day, VMC shakedown. Mechanics are people too, and sometimes leave controls, switches, and even more critical items out of "normal" position.
- Make the first time you fly a specific airplane a night flight. Until you fly it yourself, you don't know what works ... and what doesn't. You also want to be familiar with what's "normal" for that airplane, because abnormalities will be less obvious at night.
- Fly at night in an airplane you've not flown recently. Don't night-fly until you feel very comfortable flying that specific airplane.
- Fly at night if you have any unexplained -- and uncorrected -- electrical glitches.
- Fly past a good airport when you have a problem at dusk or in full darkness.
- Fly to the limit of the airplane's fueled range at night. There's a good reason the FARs require greater fuel reserves at night. Landing and refueling options are reduced after hours, and you may need to fly farther to make it to an alternate airport.
- Fly after a full day of work unless you get some real rest before departure. You need to know you won't be too fatigued at the end of your night flight.
- Plan risk avoidance, and stick with your plan. It did me no good to have a plan to stay overnight if my annual wasn't finished by a certain time, and to have even brought along an overnight bag, if I didn't have the discipline to stick with my plan when my "no-go" time passed.
- Plan a night-VFR trip as if you were planning for IFR, including routes, minimum altitudes for each flight segment, alternate airports and added fuel reserves.
- Use your checklists, even when you are comfortable in the airplane. Complacency can be worse than unfamiliarity, and complacency can kill -- especially at night.
- Actively monitor electrical load and alternator/generator output throughout the flight. Divert and land at the nearest suitable airport if an electrical problem arises.
- Crosscheck vacuum gauges and other instruments frequently, and land quickly if a failure occurs.
- Plan your fuel burn and check that fuel remaining is as expected at waypoints along your flight. Recompute "fuel remaining" at the destination regularly. Divert and land at the nearest suitable airport if fuel reserves drop below legal -- and safe -- limits.
- Perform a "blind cockpit check" before takeoff. In Air Force flight screening, we weren't allowed to solo before we could sit in the cockpit and immediately touch any indicator or control on command -- while blindfolded. Develop this level of comfort with the airplane before you fly it at night.
- Practice your emergency checklists. You need to be ready to flawlessly accomplish the engine troubleshooting, maximum glide and off-airport landing checklists should for any reason power be interrupted in flight.
- Cancel any night flight when you are not completely confident the airplane -- and you -- are airworthy.
Nighttime Engine Failures
There's an old saw about engine failures at night: If the engine quits, turn on the landing light. If you don't like what you see, turn off the landing light.
Many pilots feel night, single-engine flight is too risky. Others say the engine doesn't know it's dark outside, and it's not more likely to quit. That's true, but it's also true that most multiengine airplanes have better electrical and other system redundancy than most single-engine airplanes.
If engine reliability itself is what worries you, however, you can avoid the greatest likelihood of engine failure by practicing good fuel management. My research of NTSB reports shows that well over three-fourths of all nighttime engine failures result from either fuel starvation (running out of fuel in the tank feeding the engine and not switching to another tank with fuel in it before hitting the ground) or fuel exhaustion (truly "running out of gas").
Whether you're flying a single-engine airplane or a twin, to avoid the most likely engine failure:
- Take off with sufficient fuel to make your destination plus a very comfortable reserve.
- Lean the mixture to obtain the expected fuel flow at your selected cruise-power setting.
- Monitor the fuel burn in flight by as many means as possible (fuel burn x time; fuel gauges; trim feel as fuel burns from one tank to another; fuel totalizer if installed) and consider landing at a nearby airport if your fuel state becomes ambiguous because of conflicting indications. Remember, "book" fuel flow is a prediction; "actual" fuel burn is what's really important.
- Follow a strict, written schedule for fuel management (switching from one fuel tank to another in cruise).
- Observe all fuel-systems limitations that apply to the aircraft. Know how much fuel you can't use, and be sure to arrive at destination (or your alternate) with enough fuel in a tank that's approved for use during landing.
- Visually check for fuel streaming back from loose or leaky fuel caps -- periodically shine your flashlight outside to check. Pilots of high-wing airplanes can look for fuel droplets or mist off the wing's trailing edge behind the fuel caps and around fuel-strainer drains.
- Switch tanks near a lighted airport just in case a plugged fuel vent or other hazard prevents "good" fuel from reaching your engine.
- Recheck your estimated time of arrival (ETA) regularly to account for unexpected headwinds, and recalculate fuel requirements as the ETA changes. Don't hesitate to land early if you're eating into your preplanned fuel reserve.
Other than fuel mismanagement, engines rarely quit without at least some warning. Monitor engine indications (oil temperature and pressure, fuel-flow rates or pressure, cylinder-head and exhaust-gas temperatures, ammeter or voltage meter) in flight and record the indications over a series of daylight trips. You'll likely find that all indications are quite steady and predictable from flight to flight. Record "normal" indications and frequently compare those to what you actually observe on later flights. You might even use a grease pencil to mark the "normal" needle position for each instrument in your airplane. You'll not only be able to tell your oil pressure is "in the green," but, more accurately, it's precisely what is "normal" for that engine.
Night Risk Management
There's a lot more to know about night flight, including a good section in the Airplane Flying Handbook (FAA-H-8030-3A), Chapter 10. Using that knowledge safely hinges on your ability to manage the risks of night flying.
Fly safe, and have fun!
Thomas P. Turner's Leading Edge columns are collected here.