Near-collision between two aircraft near Bern-Belp Airport

Casualties unknown • 3.5 NM östlich vom Flughafen Bern-Belp LSZB, BE, CH

A Cirrus SR20 and a Piper PA-28 narrowly avoided a mid-air collision during an IFR training flight and a VFR flight near Bern-Belp.

What happened

On 24 June 2008, a Cirrus SR20, registration HB-KHF, was conducting an IFR training flight departing from Bern-Belp Airport. The crew, consisting of a flying instructor and a trainee pilot, was following a standard departure route. Simultaneously, a Piper PA-28-181, registration HB-PPV, was operating a VFR flight from Grenchen toward Bern.

During the flight, the air traffic controller at Bern Tower provided several pieces of traffic information. While the pilot of the HB-PPV was aware of the departing HB-KHF, the aircraft were on nearly opposite courses. At approximately 14:24 UTC, the two aircraft converged approximately 3.5 NM east of Bern-Belp. The minimum separation reached was only 0.1 NM laterally and 200 ft vertically.

The investigation

The investigation examined radar recordings, air traffic control transcripts, and pilot statements. It was established that the air traffic controller was managing a complex situation involving multiple aircraft, including a Beechcraft KingAir performing calibration flights.

In the HB-KHF, the crew's Traffic Advisory System (TAS) triggered an audio alert, notifying them of nearby traffic. This allowed the instructor to perform an evasive maneuver, involving a left turn and a slight descent. In the HB-PPV, the pilot spotted the KingAir early but did not detect the lower-flying Cirrus until the very last moment, at which point he applied slight control inputs to increase vertical separation.

Findings

The separation between the HB-KHF and HB-PPV was extremely narrow, with a vertical difference of only 200 ft.
The pilot of the HB-PPV identified the opposing aircraft late due to the Cirrus being positioned below his line of sight.
The HB-KHF crew was alerted to the danger by their onboard Traffic Advisory System (TAS), which provided an audible "traffic, traffic" warning.
The convergence was so close that the turbulence from the passing HB-PPV caused the right door of the HB-KHF to disengage from its lock, forcing the crew to abort the training flight and return to Bern.

Probable cause

The near-collision was caused by the close convergence of two aircraft on opposite headings, where the lower altitude of the Cirrus SR20 made it difficult for the Piper PA-28 pilot to detect the traffic until the separation was critically low.

Frequently asked questions

What happened in the 2008-06-24 aircraft accident near 3.5 NM östlich vom Flughafen Bern-Belp LSZB, BE, CH?

A Cirrus SR20 and a Piper PA-28 narrowly avoided a mid-air collision during an IFR training flight and a VFR flight near Bern-Belp.

What aircraft was involved and where did it happen?

The accident on 2008-06-24 involved a aircraft, registration HB-KHF, at 3.5 NM östlich vom Flughafen Bern-Belp LSZB, BE, CH.

What was the probable cause of the accident?

The near-collision was caused by the close convergence of two aircraft on opposite headings, where the lower altitude of the Cirrus SR20 made it difficult for the Piper PA-28 pilot to detect the traffic until the separation was critically low.

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