The flight departed Dallas Executive Airport at 6 a.m. CST on an instrument flight plan to Brownwood. Takeoff, climb-out, and cruise were uneventful, and upon arrival the pilot was cleared for a visual approach to Runway 35 at 6:42 a.m. While descending, the Bonanza struck power lines and trees. Witnesses heard the airplane overhead and then an explosion. One witness reported seeing the airplane before the crash, at about 500 feet agl three miles south of the airport and heading north. The NTSB report did not speculate on whether the pilot-controlled medium intensity runway lights were on at the time of the accident.
Weather at Brownwood was reported as winds 360 degrees at nine knots, visibility 10 statute miles, sky clear, temperature 57 degrees Fahrenheit, dew point 45 degrees F. Witnesses to the accident said that it was dark.
After the accident, the investigator conducted a test, with the help of the local fire department, to see if the pilot could have seen the runway from the point at which the Bonanza hit the wires. On a night with light and weather conditions similar to those at the time of the accident, the investigator used a ladder truck to raise numerous firefighters to the height of the wire impact. All indicated that at a height of 40 feet the unlighted airport was clearly visible, but many thought they were 150 to 200 feet above the ground. Because of a lack of lighting and sloping terrain, they experienced a "black hole" effect with no visual horizon.
The NTSB determined the cause of this accident to be the failure of the pilot to maintain proper altitude and clearance while on final approach. Contributing factors included the pilot's lack of familiarity with the airport, the dark night light conditions, the lack of visual approach glide slope indicators (VASI), and spatial disorientation.
The pilot had 786 hours total time, 636 of which were in the accident airplane. He also had 94 hours of total night experience, with five hours in the last year and three on the morning of the accident.
Landing at an unfamiliar airport at night can be as difficult as an instrument approach down to minimums. The pilot's ability to perceive a natural horizon can become impaired when flying over water, at night, in sparsely populated areas, and in low-visibility conditions. The lack of a natural horizon for VFR pilots can lead to spatial disorientation. If you are flying into dark, low-light airport, use extra caution and don't be afraid to rely on your basic instrument skills.
For more information about spatial disorientation and techniques for operating at black-hole airports, see the AOPA Air Safety Foundation's Spatial Disorientation Safety Advisor.
Kristen Hummel manages the GA accident database for the AOPA Air Safety Foundation. She holds a commercial pilot certificate with multiengine and instrument ratings.