This time of year, those of us who live north of about the thirty-fourth parallel get intimately acquainted with the cold. But temperatures aren’t the only things that drop during the winter. The length of the day reaches its yearlong low—so if you fly before or after work, you probably do so in the dark.
Your instructor was right when he or she pointed out that the aircraft doesn’t know it’s dark outside. Unfortunately, pilots are less robust. The things we’re not as good at during the dim side of the circadian cycle include some that are important to flight. One is staying awake. Another is seeing where we’re going.
Falling asleep in the cockpit is chiefly a risk on solo flights. It’s fairly hard to imagine two general aviation pilots dozing off at the same time, although there have been some well-publicized examples among long-haul airline crews. In GA, asleep-at-the-yoke doesn’t happen often—a good thing, since the resulting impact is usually uncontrolled. Eighty percent of those accidents are fatal. (The rest are incredibly lucky.)
For VFR pilots, not seeing where you’re going is a problem with both short-term and long-term aspects. The former includes the difficulty of keeping the aircraft upright if the horizon’s not distinct. Keeping the shiny side up raises an almost equally urgent concern: that of not running into anything solid. An appropriate choice of altitude takes care of that—if the altitude’s really appropriate. Investigators are still trying to figure out why an instructor in Virginia allowed his student to level off at 3,000 feet on a night cross-country to a mountain airfield whose elevation is 3,800.
It makes sense to treat any night flight as if it is IFR—not just while choosing altitudes, but in navigational planning. Landmarks that would be unmistakable in daylight disappear at night. With little opportunity to cross-check, dead reckoning may not be the best choice, either. In a classic example of NTSB understatement, a pilot who had flown his computed heading from Kingman, Arizona, to Boulder City, Nevada, “was surprised when local law enforcement informed him that he was in Seligman, Arizona, instead.” It turned out his calculated heading was just about 180 degrees off—and his first clue was encountering a hillside where the traffic pattern should have been. That happened at about 12:30 a.m. on a moonless November night.
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