Incident Overview
On 19 November 2019, at 11:46 local time, a serious airprox occurred near Lausanne-La Blécherette aerodrome (LSGL) during final approach to runway 36. The two aircraft involved were a Schweizer HU269 helicopter (registration HB-ZLB) and a Beechcraft BE9L King Air (registration D-ICTR). The minimum separation was 70 m horizontally and 400 ft vertically.
Aircraft and Crew
The helicopter, operated by Héli-Lausanne SA, was on a private VFR flight that had departed from and was returning to LSGL. The sole pilot, a Swiss national born in 1982, held a private pilot license for helicopters (PPL(H)) with 151 total flight hours, of which 117 were on type. The aircraft was a single-engine helicopter.
The King Air, privately owned and operated, was on a private VFR flight from Donaueschingen (EDTD), Germany, to LSGL. The crew consisted of a commander and a safety pilot. The commander, a German national born in 1969, held a commercial pilot license for aeroplanes (CPL(A)) with 5600 total hours, including 330 on type. The aircraft was a twin-turbine aeroplane.
Flight Progress
The helicopter pilot completed a local flight and elected to join the final approach for runway 36 via the south sector. She reported joining the south sector at 3400 ft QNH and later established on long final at 3100 ft QNH, approaching higher than usual to avoid turbulence from the Bise wind.
The King Air crew cancelled their instrument flight plan at the Saint-Prex VOR and continued VFR to join the south sector. The commander reported on the Lausanne AFIS frequency at 3300 ft QNH, 5 NM from the airport. While on long final at 2.5 NM, the crew sighted the helicopter ahead and above. Judging their higher approach speed and sufficient vertical separation, the commander decided to overtake the helicopter from below and to the right, announcing their intention on frequency.
The helicopter pilot heard a fragmented transmission about traffic passing below and shortly thereafter saw the aircraft beneath her. She reduced speed to increase separation. The approach and landing continued without further incident.
Communication and Airspace
Lausanne-La Blécherette aerodrome has no control tower; pilots use a common frequency for blind transmissions. French and English are the official languages. In this incident, the helicopter pilot communicated in French, while the King Air crew used English. The airspace was class G, with AFIS service.
Analysis and Conclusion
The investigation concluded that the serious incident was due to a dangerous proximity between a helicopter previously established on final for runway 36 and a twin-turbine aircraft overtaking it from below. The tactic of overtaking preceding traffic from below during final approach was noted as risky, especially in case of unexpected events. Factors contributing to the incident included the use of different languages in radiotelephony and the large difference in approach characteristics between the two aircraft.