Report on serious aircraft incident in the airspace between Lysefjorden and Hunnerdalen in Rogaland county, Norway on 3 January 2020 involving Cessna 172S, LN-AZA

Aviation report 2020/13

On January 3rd 2020, an IFR training flight was cancelled en route because of bad weather conditions. The instructor and the student chose to fly from the Stavanger area back to Arendal over mountain areas. They entered Instrument Meteorological Conditions (IMC) and icing conditions in flightlevel FL100 – FL110. Significant icing occurred.

The aircraft was certified for IMC, but not to be used in icing conditions. The crew observed slow flight controls and aircraft vibrations. With assistance from the air traffic services, the crew changed the route and made descent to lower altitude where they got rid of the ice. The aircraft landed normally at Stavanger airport Sola. 

After this serious incident, the flight school has implemented measures to ensure that risk of icing is adequately considered during the planning of longer IFR flights. The main measure, do not fly IMC when the 0-isotherm is below Minimum Safe Altitude, could have prevented the incident in question. The Accident Investigation Board Norway believes that similar precautions should be consider by anyone flying IFR with aircraft that are not certified for icing conditions.

Facts

Location Sola TMA (ENZV), between Lysefjorden and Hunnedalen, Norway
Occurrence date 03.01.2020
ICAO Location indicator ENZV
Aircraft Cessna 172 Skyhawk
Operator OSM Aviation Academy AS
Registration LN-AZA
Meteorological conditions IMC
County Rogaland
Type of occurrence Serious incident
Type of operation Training
Category of operation Light, aeroplane (< 5 700kg)
Aircraft category Landplane, Single-engine, Piston engine
FIR/AOR ENSV (Stavanger ATCC)

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