Serious Incident at Bern Airport Involving Wake Turbulence from Helicopter (HB-ZOK)

Q: What aircraft was involved and where did it happen?

The accident on 2016-08-12 involved a ROBINSON HELICOPTER COMPANY R66, registration HB-ZOK, at Bern Flughafen (LSZB), BE, CH.

On August 12, 2016, a ROBINSON HELICOPTER COMPANY R66 (registration HB-ZOK) was involved in an aviation accident near Bern Flughafen (LSZB), BE, CH. Investigators recorded the probable cause as: The serious incident was due to the aircraft flying into the helicopter's wake turbulence. The lack of awareness of the danger of helicopter wake turbulence by both air traffic control and the flight crew was determined to be causal. This summary draws on records from the Swiss Transportation Safety Investigation Board (STSB / SUST).

Sourcesthe Swiss Transportation Safety Investigation Board (STSB / SUST)Primary reportUpdated 1785034239Data API Editorial standards

On 12 August 2016, an Aero AT-3 (HB-SRC) encountered wake turbulence from a Robinson R66 (HB-ZOK) during a touch-and-go at Bern Airport, causing a sudden 70° roll. The incident was due to the aircraft flying into the helicopter's wake and a lack of awareness of the danger by ATC and flight crews.

Event Details

A serious incident occurred on 12 August 2016 at Bern Airport (LSZB) involving two aircraft: an Aero AT-3, registered HB-SRC, and a Robinson R66, registered HB-ZOK. Both aircraft were conducting training flights. The incident resulted in a loss of control of the Aero AT-3, which was narrowly avoided.

Aircraft and Crew Information

The Aero AT-3 is a single-engine, two-seat, low-wing light aircraft with a maximum takeoff weight of 582 kg. It was operated by Alp-Aircraft GmbH and crewed by a flight instructor (Swiss, born 1957, holding a CPL(A) with 2086 total hours, 555 on type) and a student pilot (Swiss, born 1971, with 11 total hours). The Robinson R66 is a single-engine turbine helicopter with a maximum takeoff weight of 1225 kg. It was operated by Mountain Flyers 80 Ltd. and crewed by a flight instructor (Swiss, born 1973, holding a CPL(H) with 4615 total hours, 18 on type) and a student pilot (Swiss, born 1984, holding a PPL(H) with 261 total hours).

Sequence of Events

At 11:23 LT, the Aero AT-3 departed from Runway 14 for circuit training with touch-and-go landings. At 11:28, the helicopter crew contacted the aerodrome control officer (ADCO) and received clearance for an approach via the West sector. The helicopter was instructed to cross the runway axis expedite. At 11:34, the ADCO advised the Aero AT-3 of the helicopter's position. The Aero AT-3 continued its approach for a touch-and-go. After the helicopter crossed the runway, the Aero AT-3 touched down and lifted off. At about 10 m above ground near taxiway Delta, the aircraft abruptly rolled left to 70° of bank. The flight instructor took control and prevented a crash. The helicopter landed on helipad H2 at 11:35.

Meteorological Conditions

The weather was dry and calm with light winds. Wind at the time was from 130° at 3 knots, as reported to the Aero AT-3. There were high clouds with occasional sunshine.

Investigation Findings

The investigation determined that the serious incident was caused by the Aero AT-3 flying into the wake turbulence of the Robinson R66. A lack of awareness of the danger associated with helicopter wake turbulence, on the part of both the air traffic control and the flight crews, was identified as causal.

Probable cause

The serious incident was due to the aircraft flying into the helicopter's wake turbulence. The lack of awareness of the danger of helicopter wake turbulence by both air traffic control and the flight crew was determined to be causal.

Loss of control in flight

2016-08-12: ROBINSON HELICOPTER COMPANY R66 (HB-ZOK) — Bern Flughafen (LSZB), BE, CH