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2020/16 eng

Report on serious aviation incident west of Førde Airport Bringeland on 14 November 2016 involving ATR 72-212A, OY-JZC, operated by Jet Time AS

SAS Flight 4144 was operated by the Danish airline Jet Time AS on behalf of SAS. En route from Bergen to Ålesund, west of Førde Airport Bringeland, control of the aircraft was temporarily lost in severe icing. It banked uncontrollably and lost considerable altitude. The crew regained control of the aircraft, and left the area where the icing had occurred. The last part of the flight was conducted along a more westerly track where icing conditions were avoided. A normal landing was performed at Ålesund Airport Vigra. There were no injuries to passengers or crew. Neither was there any damage to the aircraft. This and two other serious icing incidents involving the ATR 72-212A illustrate the importance of monitoring airspeed and climb in order to operate the aircraft within its defined performance limitations. AIBN is of the opinion that icing should be a priority item in risk analyses for airlines that plan to operate in Norway during the icing season, and that it is important to take the characteristics of the aircraft type into consideration. Less than three months after the incident, SAS terminated the routes and Jet Time AS ceased operating the ATR 72-212A in Norway.


Animation of the control loss.

Moderate icing had been forecasted along the route. As SAS4144 climbed through FL137, south of Sognefjord, the crew observed that they had encountered severe icing.

Just before the loss of control, the airplane climb performance had decreased significantly. The crew therefore decided to divert towards the coast in order to avoid icing conditions and the mountaneous terrain inside the coast line. However, their decision proved to be too late. The control loss occurred during the turn towards the coast. It appeared suddenly to the crew, whose initial reaction was not optimal. AIBN is of the opinion that the crew became startled as they did not disengage the auto pilot. 

The crew have later expressed that they were expecting to exit the icing conditions sooner by climbing above the clouds. The clouds containing icing conditions did, however, go much higher than they realized. As AIBN see it, this could explain why the descision to divert was made too late to avoid the control loss.

AIBN has also reviewed the incident involving SAS4144 with a focus on possible contributing factors that may be directly related to wet lease, foreign operators unfamiliar with Norwegian conditions, lack of transfer of information between the Scandinavian aviation authorities, or the possibility of the object of regulatory inspection (Jet Time AS) falling between two stools. No such causal connections have been uncovered. 

Published 10.09.2020

Facts

Location 70 NM NNE of Bergen, Norway
Occurrence date 14.11.2016
Aircraft ATR 72
Operator Jet Time A/S
Registration OY-JZC
Meteorological conditions IMC
County Vestland
Type of occurrence Serious incident
Type of operation Scheduled air transport
Category of operation Heavy, aeroplane (> 10 000kg)
Aircraft category Landplane, Multi-engine, Turboprop/turboshaft
FIR/AOR ENSV (Stavanger ATCC)