What happened
On July 10, 2015, a Cessna FR172E, registration SE-FBT, was attempting a departure from a private gravel airstrip on Vannø and Troms, Norway. The pilot intended to fly to Tromsø Airport, Langnes. The airstrip is approximately 400 meters long and is situated near steep terrain that rises to 750 meters on the northern side of the runway.
During the takeoff roll on runway 08, the pilot utilized flap 10 and rotated the aircraft at approximately 60 knots. Shortly after liftoff, the aircraft's left wing and tail lifted abruptly. The aircraft traveled only about 20 to 30 meters in the air before striking the ground. The impact caused the aircraft to veer sharply to the right, eventually coming to rest 9 meters from the edge of the runway. The pilot was uninjured, but the aircraft sustained a broken nose gear strut and a damaged propeller.
The investigation
The Norwegian Safety Investigation Authority (NSIA) examined meteorological data and local airfield conditions. While the pilot observed a windsock indicating a 10-knot wind from 060 degrees just prior to departure, meteorological records from nearby stations revealed more complex conditions. Data from the Torsvåg station indicated light winds at sea level, but observations at an altitude of approximately 200 feet showed wind speeds of 10-12 m/s (roughly 19-23 knots) from the north/northwest.
Findings
- The aircraft was subjected to downdrafts or wind shear immediately after takeoff.
- The terrain surrounding the airstrip creates a risk of unpredictable wind patterns, particularly as wind speeds increase over the nearby ridges.
- At the time of the accident, the aircraft was highly vulnerable to these vertical wind movements due to its low altitude and low airspeed following rotation, leaving minimal margin for corrective maneuvers.