Report on aviation accident at Oslo airport Gardermoen, Norway on 11 January 2017 with Cessna Aircraft Company 560 Encore, LN-IDB, operated by Hesnes Air AS
The crew lost control of the aircraft shortly after taking off from Gardermoen. From a height of approx. 1,400 ft above the ground, the nose of the aircraft tipped down abruptly. In order to regain control and prevent the aircraft from colliding with the ground, the controls were forcefully pulled. The aircraft levelled off approx. 170 ft above the ground before the crew could continue climbing. Due to large G forces in connection with the incident, the aircraft was substantially damaged. AIBN has determined that a probable explanation for the aircraft's sudden dive is that the tailplane stalled as a result of icing caused by contamination from slush spray from the runway and/or from falling snow and sleet. The investigation has not revealed any technical malfunctions in the aircraft and its control systems.
There were icing conditions at, and in the airspace above Oslo Airport Gardermoen. After flying from Switzerland for more than two hours in approximately minus 50°C, the aircraft's structure (fuselage and wings) was chilled. The aircraft's ground stop lasted approximately 15 minutes at an air temperature of 0°C. The taxiways and runway were covered with 3-6 mm of slush and it was snowing when the aircraft took off without being de-iced.
The crew, which consisted of a Commander and a First Officer, had flown from Bern in Switzerland to Gardermoen with a passenger on board. After disembarking the passenger at Gardermoen, the aircraft was scheduled to be flown to its home base at Sandefjord Airport Torp without passengers on board. The crew had planned to make the ground stop as short as possible and if the weather conditions permitted, they would avoid de-icing. According to the crew, the snow did not accumulate on the wings before departure, they could only see melted water on the wing surfaces and therefore decided not to de-ice the aircraft.
The aircraft's anti and de-icing systems on the wings and tailplane were switched on, but AIBN's assessment is that the systems were not suitable to remove this relevant type of ice and snow. With the existing conditions at Gardermoen during the ground stop, AIBN is of the opinion that the aircraft should have been de-iced before take-off.
AIBN is issuing two safety recommendations based on this investigation. One goes to the aircraft manufacturer Textron Aviation / Cessna where the manufacturer is asked to inform the customers about the accident and the risk of tailplane stalling. The other goes to the Civil Aviation Authority Norway and deals with the Authority's routines when approving organisation of airlines.
Safety recommendation SL no. 2020/01T
On Wednesday, 11 January 2017, the crew lost control of a Cessna 560 Encore at low altitude after take-off. The most probable explanation for the aircraft's sudden dive, is that the tailplane stalled as a result of icing from slush spray from the runway and from falling snow and sleet. The aircraft's rubber de-icing "boots" were in automatic mode and inactive during the take-off and when the stall occurred. Textron/Cessna has informed AIBN that they not previously have experienced loss of control as a result of icing on the tailplane on their aircraft models.
AIBN recommends that Textron/Cessna inform all its customers that operate Cessna Citations about this accident and about the risk of contamination on the tailplane in the form of ice or other substances witch can result in the tailplane stalling.
Safety recommendation SL no. 2020/02T
On Wednesday, 11 January 2017, the crew lost control of a Cessna 560 Encore at low altitude after take-off. The Accountable Manager (AM) held several key roles within safety. The presumably monitoring and corrective roles, as appears to be the intend through EASA’s PART-ORO, were thus absent.
AIBN recommends that the Civil Aviation Authority Norway changes its routines for approving organisations in line with the intent of the EASA regulation.
|Location||Oslo airport Gardermoen, Norway (ENGM)|
|ICAO Location indicator||ENGM|
|Type of occurrence||Accident|
|Type of operation||Commercial, other|
|Category of operation||Medium, aeroplane (5 700 - 10 000kg)|
|Aircraft category||Landplane, Multi-engine, Turbofan/Turbojet|
|FIR/AOR||ENOS (Oslo ATCC)|