A probable cause found by the NTSB pointed to the "pilot's failure to maintain a positive climb rate after takeoff due to spatial disorientation (somatogravic illusion
Analysis by the UK's Air Accidents Investigation Branch, aimed at assessing the effect of somatogravic illusion
, concluded that the crew could have perceived that the aircraft had inverted as it transitioned rapidly from climb to descent.
The investigators concluded: "Evidence suggests that the flight crew may have been subject to somatogravic illusion
caused by the helicopter's flight path and the lack of external visual cues.
Investigators added: "Evidence suggests the crew may have been subject to somatogravic illusion
caused by the helicopter's flight path and the lack of external visual cues."
This is the somatogravic illusion
in which the otolith organs in your ear behave as if you were tilting your head backwards.
Air accident investigators said yesterday they believe Capt Furniss, one of the Air Corps' most experienced teachers, was misled by an airborne phenomenon known as somatogravic illusion
The somatogravic illusion
is powerful--the inner ear tells the pilot that the airplane is climbing when it is accelerating in level flight.
When adding power and accelerating during a go-around, especially in more powerful aircraft, the otolith organs in the inner ear send signals to the brain that create the somatogravic illusion of pitching up abruptly.
For relatively low-time IFR geezers like me, the first experience of the somatogravic illusion at 200 feet on a missed in hard IMC was quite an awakening.
More scientifically labeled "Somatogravic Illusion
," it describes the result of fluid moving in a pilot's inner ear when an aircraft accelerates.
In its curriculum for teaching student pilots, the FAA primarily focuses on the aeromedical causes of spatial disorientation--the vestibular-ocular system, somatogyral and somatogravic illusions
, visual illusions and otolith organs.