ZK-FGS - Spatial Disorientation in Poor Weather
Location: Waipara River, Cantebury, NZ
Date: 07 August 2005
Type of Aircraft: Cessna 182R
Synopsis
A pilot and his wife were on the final leg of a flight that they were undertaking. The flight departed from Nelson airport at 1.42PM. Their destination was a private airstrip, about 18km west of Christchurch. A Radar track of the aircraft was recorded for its entire journey. They travelled through Malborough Sounds, passed Woodbourne, and down the east coast of the south island, towards Christchurch. At Kaikoura it was noted that they decended gradually, at first down to 600 feet, and then going below the minimum legal height of 500 feet. At 3.15pm the aircraft disappeared from radar. The aircraft was reported missing the next day by the Pilot's neighbour, who had noticed that the aircraft had not returned as expected.
Investigation
The pilot held a Private Pilots Licence, however his class 2 medical certificate had expired in July 2005 and had not been renewed. The pilots total flight time could not be determined, as his log book was in the aircraft with him and was unreadable. The pilot did not hold an Instrument Rating, and so should have been maintaining visual flight at all times.
The aircraft had a current airworthiness certificate, with no recorded defects.
At the time of the flight, a low pressure system existed over New Zealand. Satellite imagery revealed heavy cloud over the east coast of the South Island. The pilot obtained weather forcasts for Nelson, Woodbourne and Christchurch, but the Christchurch weather forcast was later updated, and predicted worsening weather conditions, with low cloud and poor visibility. This weather was indicated in Area Forcast, but the weather forcast that the pilot obtained did not include the Area Forcasts for where the pilot would be travelling. After take off, the pilot did not attempt to get any updates about weather at his destination.
Other pilots flying in the area reported that they had to either divert their flights or return the way they had come, as weather in the area was below visual flight minimums.
The aircraft wreckage that was recovered from the ocean showed significant damage which would have occured from a high speed impact.
Conclusion
- The pilot did not have a valid medical certificate, and therefore was not appropriatly licenced to carry out the flight
- The pilot probably had an inaccurate perception of enroute weather conditions approaching his destination
- The pilot continued to fly at a low altitude and into deteriorating weather conditions.
- It appears that the pilot became spatially disorientated, and because he did not have the training to deal with this, could not control the aircraft and impacted the sea.
Lessons Taken from this Accident
This information has been provided in the CAA1 accident report as to what has been implemented since this accident occured:
"The January/February 2006 CAA Vector safety publication, which is issued to all document holders, contained an article “178 Seconds to Live”. This article examines the consequence of “risky weather decisions” and explains the phenomenon of spatial disorientation."
"The investigation revealed that, on the day of the accident, other pilots conducting private VFR flights along the east of the South Island had also been pressing on into conditions where they could not comply with the prescribed VFR minima, flying at low level in an attempt to remain clear of cloud and penetrate through the weather system. It appears that this may be a common practice in certain sectors of the aviation community, and should be actively discouraged."
"Where external visual references do not exist during flight in IMC, pilots who are proficient in instrument flying use strict standard operating procedures. They maintain a constant scan of all of the primary flight instruments. This counteracts any potential inadvertent response to strong signals from the dominant sensory perception mechanisms of the body such as the vestibular apparatus, (organs in the inner ear used for motion sensing), which can be a significant factor in why pilots become spatially disorientated. During PPL(A) training the student must demonstrate an ability to fly using instruments alone, however the PPL student is primarily trained to look outside the aircraft for visual reference. A ‘visually’ proficient pilot would find flight in IMC to be a very demanding and stressful situation and would tend to look outside the aircraft for reference, particularly in partial IMC, even in an aircraft which is fully IFR equipped."
"The tendency of pilots who are becoming unknowingly spatially disoriented, is generally to progressively apply control inputs to correct a perceived adverse aircraft attitude. This can result in departure from controlled flight before the pilot realises, and can react to, what is occurring. This effect is exacerbated when the aircraft is climbing, descending, turning or accelerating. A spiral dive will rapidly ensue if control is not recovered quickly and, depending on the conditions at the time, the pilot may be unable to regain a sense of orientation. This is particularly hazardous if this occurs at a low altitude. Then, impact with the ground, or in this case the sea, is almost inevitable."
Want to know more?
- CAA Accident Report
- The full accident report provided by the New Zealand Civil Aviation Authority
- Situational Awareness
- A page about how to maintain situational awareness.
- Wikipedia - Spatial Disorientation
- Information about Spatial Disorientation, and how it affects pilots.
- Vector 2006 Jan-Feb
- An issue of Vector magazine with the article that was printed after this accident occured, "178 Seconds to live".
Contributors to this page
Authors / Editors
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