Cessna 172R N2435X accident near Key West, Florida

Probable cause

The non-instrument-rated pilot's spatial disorientation during night, over-water, low-ambient-light conditions, which resulted in the airplane impacting the ocean.

NTSB analysis

The non-instrument rated pilot performed a touch-and-go practice takeoff and landing at an airport located on an island at night. Thereafter, the flight continued over water at a low altitude. A pilot of a commercial flight inbound to the island observed the accident airplane on his traffic collision and avoidance system (TCAS) and additionally noticed the reflection of its landing light on the water. When the reflection disappeared, the TCAS contact also disappeared, likely due to the airplane impacting the water. After rescue, the pilot could not recall much of the event, but did remark that there were no mechanical malfunctions or failures with the airplane that would have precluded normal operation. At the time of the accident, the moon's phase was waxing crescent with 18 percent of the disk illuminated. Federal Aviation Administration Advisory 60-4A states that, "The attitude of an aircraft is generally determined by reference to the natural horizon or other references on the surface. If neither horizon nor surface references exist, the attitude of an aircraft must be determined by artificial means from the flight instruments. ...Spatial disorientation to a pilot means simply the inability to tell which way is up....Lack of natural horizon or surface reference is common on over water flights, at night, and especially at night in extremely sparsely populated areas, or in low visibility conditions."

Text from the NTSB. Open the NTSB docket for ERA10LA421 for the full record.