Pilots flying without visual references, especially in times of very low visibility are highly susceptible to spatial disorientation, one of general aviation's biggest killers. On October 25, 2002 a pilot flying a Cessna 182 became disorientated and crashed while being vectored for an approach into the Piedmont Triad International Airport in Greensboro, NC. The pilot and both of his passengers were killed.
On the day of the accident, the pilot attempted two ILS approaches to Runway 33 at the Smith Reynolds Airport in Winston Salem, NC. Shortly after being cleared for the first ILS approach, the pilot called Greensboro Approach and declared an emergency, stating that was "totally disoriented." Approach Control instructed the pilot to climb to 6,000 feet in order to get on top of the overcast. The pilot was then given a radar vector to re-intercept the Runway 33 localizer. During the approach, the pilot was advised that he was off course, and instructions to climb to 4,000 feet were issued. ATC issued another heading to intercept the localizer again, and the pilot was unable to maintain the inbound course.
Approximately 50 minutes after the pilot initially contacted Greensboro Approach, he advised them his fuel status was low. In an effort to help the pilot, approach then vectored the pilot towards Piedmont Triad for an Airport Surveillance Radar (ASR) approach. The last instructions given to the pilot were to maintain 2,500, turn 10-degrees to the right to re-intercept the inbound course. The airplane was found in a heavily wooded area near the outer marker. Greensboro weather at the time of the accident was one-half mile (statute) visibility with mist, and the ceiling was100 feet overcast.
The NTSB determined the cause of this accident to be the pilot experiencing spatial disorientation, which resulted in a loss of control and collision with trees.
Many pilots don't even know what spatial disorientation is, or how to cope with it in the airplane. What is worse, severe disorientation can happen so subtly that a pilot may not realize how serious the situation is until it is too late. For more information on how to prevent spatial disorientation and how to cope if you experience it, see the AOPA Air Safety Institute's Safety Advisor, Spatial Disorientation.
This accident report as well as others can be found in ASI's Online Database.