Three people were killed on July 16, 1999 when a Piper Saratoga (registration N9253N) piloted by John F. Kennedy Jr. crashed into the Atlantic Ocean off the coast of Martha's Vineyard, Massachusetts, USA (Wikipedia, 2012). While crossing a 30-mile stretch of water towards its destination, the aircraft took a number of random descending turns (NTSB, 2000). It eventually struck the water in a nose-down attitude (NTSB, 2000). The official accident report by the National Transport Safety Board (NTSB) blames pilot error (NTSB, 2000).
|Aircraft: Piper PA-32R-301 (Saratoga), 21 September 2012|
- The pilot held a Private Pilot's Licence (PPL) without an Instrument Rating endorsement (NTSB, 2000).
- The pilot's total flight experience was about 310 hours, of which 55 were at night. The pilots estimated flight time in the accident airplane was about 36 hours, of which only 9.4 were at night (NTSB, 2000).
- The pilot obtained weather forecasts for a cross-country flight, which indicated visual flight rules (VFR) with clear skies and visibilities that varied between 4 to 10 miles along his intended route (NTSB, 2000).
- Other pilots flying similar routes on the night of the accident reported no visual horizon while flying over water because of haze (NTSB, 2000).
- An examination of the airframe, systems, avionics, and engine after the crash did not reveal any evidence of a pre-impact mechanical malfunction (NTSB, 2000).
Pilot's failure to maintain control of the airplane as a result of spatial disorientation.
The NTSB determined the probable cause of this accident to be:
"The pilot's failure to maintain control of the airplane during a descent over water at night, which was a result of spatial disorientation" (NTSB, 2000).
Under normal conditions, a VFR rated pilot would rely on visual cues to detect and maintain orientation and navigate safely to his/her destination. However such cues were not present, resulting in considerable reliance on instrument flying techniques. Techniques in which the pilot was not fully trained for (NTSB, 2000). This resulted in the pilot becoming spatially disorientated, a condition which occurs when a pilot is unable to correctly interpret aircraft attitude, altitude or airspeed, in relation to the Earth or point of reference (FAA, Spatial Disorientation).
While under this condition the pilot started a number of random manoeuvres including an initial descent which varied between 400 to 800 feet per minute (fpm) (NTSB, 2000). About 7 miles from the approaching shore, the airplane began a right turn (NTSB, 2000). The airplane stopped its descent at 2,200 feet then climbed to 2,600 feet and entered a left turn (NTSB, 2000). While in the left turn, the airplane began another descent that reached 900 fpm (NTSB, 2000). While still in the descent, the airplane entered a right turn (NTSB, 2000). The airplanes rate of descent eventually exceeded 4,700 fpm before striking the water (NTSB, 2000).
According to the official NTSB report, there were a number of human factors issues present in this accident;
First, the pilot made no attempt to request new or updated weather information as the flight progressed, even though the pilot remained within radio-range contact with a number of Air Traffic Control locations along his route (NTSB, 2000). Second, the pilot's experience and training were insufficient given the challenging conditions within which he was placed (NTSB, 2000).
As a compounding result of these conditions, the pilot suffered spatial disorientation, thus leading to an uncontrolled descent before impacting the water (NTSB, 2000).
Since this accident, the Federal Aviation Authority (FAA) has issued a number of Advisory Circulars (AC) and safety brochures on Spatial Disorientation and Visual Illusions (e.g. Spatial Disorientation: Why You Shouldn't Fly By the Seat of Your Pants), in order to provide pilots with a better understanding of illusions and encourage instrument training. This has also prompted awareness workshops and physiological training courses in approved simulators (for example; FAA - Airmen Education Programs, 2010).
Want to know more?
- Night VFR
- CAA NZ guide on Night VFR including Dark Adaption, Visual Illusions and Emergencies.
- Which way is up? poster
- A free poster by CASA Australia, aimed towards training Helicopter Pilots in Spatial Disorientation
- Airman Education Programs
- Aviation physiology courses and workshops provided by the FAA
News Report, USA Local Media
Video embedded from YouTube on 24 September 2012
Physiology of Flight: Spatial Disorientation
Video embedded from Youtube on 24 September