What happened
On March 19, 2014, at 09:38 UTC, a serious airprox incident occurred approximately 1.5 NM east of the Bern-Belp Regional Airport. A DA20-C1, registration HB-SGK, was conducting a private VFR flight toward Bern-Belp. Simultaneously, an EC635 helicopter, registration T-362, operated by the Swiss Air Force, was approaching the same airfield from the east.
The air traffic controller at Bern-Belp had cleared the helicopter for an approach via the HE reporting point and instructed the pilot of the HB-SGK to enter a right-hand pattern for runway 14 via the S reporting point. However, upon passing the S point, the pilot of the HB-SGK executed a left-hand pattern instead of the instructed right-hand approach. This deviation resulted in a dangerous convergence of the two aircraft, reaching a minimum horizontal separation of only 0.4 NM with a vertical separation of approximately 300 ft. The encounter was classified as an ICAO Category A airprox, indicating a high risk of collision.
The investigation
The SUST investigation examined the flight paths, communication between the pilot and air traffic control, and the operational environment of the Bern-Belp Class D airspace. The inquiry reviewed the flight recorder data from both aircraft, including the downlink mode S and voice recordings. The investigation also analyzed the visual approach charts used by pilots and the specific procedures governing mixed VFR and IFR traffic at the airfield.
Findings
- The primary cause of the incident was the pilot of the HB-SGK entering a left-hand pattern instead of the required right-hand pattern due to a wrong expectation of the arrival procedure.
- The pilot's incorrect expectation regarding the services and capabilities of air traffic control within the Class D airspace contributed to the error.
- Systemic factors at Bern-Belp included procedures with a low tolerance for error and an unclear representation of traffic on the visual approach charts.
Safety action
While the SUST noted that several previous safety recommendations regarding Bern-Belp had not been fully implemented to prevent such risks, no new recommendations were issued as the existing ones addressed the core issues. However, since March 2015, new visual approach charts have been published for Bern-Belph, featuring relocated or renamed reporting points and separate maps for arrival and departure routes to reduce complexity.