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Dark spiral Dark spiral

Pilot loses control during night flightPilot loses control during night flight

With the end of daylight savings time and the approach of winter, many pilots are apt to find themselves flying after dark—perhaps for the first time since early spring. The FAA defines night currency in terms of takeoffs and full-stop landings, but the en route part of night flying can also get tricky. Cruising above sparsely lit terrain on a moonless night can be tantamount to flying in IMC. A VFR-only pilot can quickly become disoriented, sometimes with tragic results.

On the night of Jan. 7, 2005, a Piper PA-28-181 Archer crashed in a sparsely populated area near Bradley, S.C. The accident site was approximately nine miles from the departure airport, and VFR conditions prevailed. The noninstrument-rated pilot and three passengers were killed.

At about 6:45 p.m., the flight departed McCormick County Airport in McCormick, S.C., for a short hop to Greenwood County Airport, 21 nautical miles to the north. The pilot had called flight service about an hour earlier to request a weather briefing for a 130 nm flight to Bennettsville, S.C., but forecast conditions were not favorable for the longer trip. No flight plan was filed.

After takeoff, the aircraft flew north over the Sumter National Forest, a relatively unpopulated area with few ground lights. The waning crescent moon had yet to rise. There were broken clouds at 2,200 feet agl and an overcast layer at 3,400 feet. Visibility was 10 miles.

At 6:56 p.m., the local 911 operator received a call regarding a possible downed airplane. Witnesses said that prior to impact, the aircraft sounded “as if in distress... [with] the engine idling high.” The wreckage was found in a wooded area about halfway between the departure airport and the intended destination.

The impact scar and debris field were consistent with a steep-angle, high-speed descent. Investigators found no evidence of mechanical malfunction. The NTSB concluded that the pilot lost control of the airplane due to spatial disorientation, which resulted in an uncontrolled descent and ground collision. The board cited the dark night conditions as a factor in the accident.

The FAA’s advisory circular on spatial disorientation describes some of the unique challenges of flying after dark: “Lack of natural horizon or surface reference is common on overwater flights, at night, and especially at night in extremely sparsely populated areas or in low-visibility conditions. A sloping cloud formation, an obscured horizon, a dark scene spread with ground lights and stars, and certain geometric patterns of ground lights can provide inaccurate visual information for aligning the aircraft correctly with the actual horizon. The disoriented pilot may place the aircraft in a dangerous attitude.”

Compounding the problem, clouds can become all but invisible at night, meaning a VFR pilot could enter IMC without warning. On the night of the accident, the ceiling was 2,200 feet and conditions were deteriorating. The pilot might have encountered clouds in addition to the disorienting darkness. With few or no visual references, he likely entered the proverbial “graveyard spiral,” a high-speed, tight descending turn that begins when rolling motion goes undetected. The disoriented pilot senses a descent but does not realize the aircraft is turning. Applying back pressure to stop the altitude loss only tightens the turn and increases the descent rate.

In addition to spatial disorientation, the challenges of night flying include unseen obstructions, “black hole” approaches, and limited options in the event of engine failure. According to data from the AOPA Air Safety Foundation’s Accident Database, the fatal VFR accident rate more than doubles after nightfall. Pilots should not necessarily be discouraged from flying at night, but it’s important to be aware that the risk goes up when the sun goes down. Night flying demands more of our attention, and it requires us to be keenly aware of—and operate safely within—our limitations and abilities.