What happened
On May 4, 2003, a Cessna 180H floatplane, registration LN-KCF, crashed into the summit of Slettefjell, west of Notodden, at an altitude of approximately 1,080 meters. The aircraft was being flown by its owner to return it from winter storage at Notodden airport to its home base at Kilen Sjøflyklubb.
The flight, which was estimated to take only 30 minutes, went missing when the aircraft failed to arrive at its destination. Search efforts involving light aircraft and a Sea King helicopter eventually led to the discovery of the wreckage the following day. The pilot, who was the sole occupant, was killed in the impact. The aircraft struck the terrain at a 3/4 angle while traveling on a heading of approximately 290 degrees, a direction opposite to the intended flight path.
The investigation
The Norwegian Safety Investigation Authority (NSIA) examined the circumstances surrounding the flight, including the pilot's experience, weather conditions, and air traffic services. The investigation established that the pilot had not flown for approximately six months prior to the accident and had limited recent experience in the specific area.
Investigators also looked into the technical state of the aircraft and the communication between the pilot and air traffic control. While the aircraft was found to be in a proper technical condition, the investigation revealed that the pilot had attempted to contact Farris Approach multiple times without success. This was due to the pilot having selected the incorrect radio frequency on the communication panel, a mistake that went unnoticed. Furthermore, the investigation found that the air traffic control sector had been merged in a manner that limited radio coverage, and other aircraft in the area did not relay the pilot's distress calls.
Findings
- The pilot likely lost control of the aircraft due to vertigo after attempting to fly under Visual Flight Rules (VFR) in conditions that had deteriorated into Instrument Meteorological Conditions (IMC).
- The pilot was flying in the wrong direction, heading north toward Åsdalsvatnet instead of the intended northeast toward Meheia.
- The pilot failed to account for deteriorating weather conditions moving in from the northwest.
- The pilot's recent flying experience was limited, and they were unfamiliar with the terrain along the intended route.
- Air traffic services failed to provide necessary assistance because the pilot's calls were not heard due to a frequency selection error and the lack of a relay from other aircraft.
Safety action
The investigation led to safety recommendations regarding air traffic control procedures and equipment design. Specifically, it was recommended that Avinor ensure stricter adherence to internal regulations regarding the merging of sectors to prevent coverage gaps. Additionally, a recommendation was made to review the design of communication panels in control positions to make the selected radio frequencies more clearly visible to controllers.