What aircraft was involved and where did it happen?

The accident on 2000-01-11 involved a CESSNA AIRCRAFT COMPANY C182, registration D-EROM, at TMA Bern nordwestlich von SHU, CH.

What was the probable cause of the accident?

The incident was caused by the pilot of the Cessna 182 entering the Bern TMA without authorization and likely operating under insufficient VFR weather conditions, leading to a critical loss of separation with an IFR flight.

TCAS Alert Averted Near Bern After Unauthorized VFR Entry

A high-risk airprox occurred in Swiss airspace when a private Cessna 182 entered the Bern TMA without authorization, triggering a TCAS alert for a Crossair Saab 2000.

What happened

On January 11, 2000, a Crossair Saab 2000, registration HB-IZF, was conducting an instrument approach to Bern Airport. While descending through the Bern TMA, the crew received a TCAS traffic alert indicating an aircraft only 500 feet vertically separated from them. The crew immediately reacted by disabling the autopilot, increasing engine power, and executing a significant climbing right turn. This maneuver prevented a collision with a Cessna 182, registration D-EROM, which was flying under VFR. The two aircraft crossed paths with a vertical separation of only approximately 300 to 400 feet.

The investigation

The investigation established that the Cessna 182 was operating a private flight from Geneva to Nuremberg. While the aircraft was under the jurisdiction of Geneva Flight Information Centre (FIC), it later transitioned to Zurich Information. The investigation found that the pilot of the Cessuna 182 had planned a route via several waypoints but had not obtained the necessary clearance to enter the Bern TMA.

Air traffic controllers in Bern initially believed the unidentified target was flying below the TMA and did not issue an immediate traffic warning. However, the pilot of the Saab 2000 proactively switched their navigation display to traffic mode to assess the situation. The investigation also noted that the radio connection between the Cessna 182 and Geneva FIC was of poor quality, which may have hindered effective communication regarding the aircraft's intentions.

Findings

The primary cause of the incident was the pilot of the Cessna 182 performing an unauthorized entry into the Bern TMA without the required flight clearance.
The pilot was likely operating in violation of minimum VFR weather requirements, as heavy fog and low cloud ceilings were present in the area, making VFR flight difficult.
The pilot's decision to climb to flight level 95, combined with an abrupt course change, placed the aircraft directly in the path of the descending Crossair flight.
The rapid and decisive actions of the Saab 2000 crew, prompted by the TCAS alert, were instrumental in preventing a mid-air collision.

Safety action

A recommendation was made to replace TCAS equipment that requires manual switching between modes with systems that provide a fully integrated, continuous optical display of intruders.
The investigation highlighted the need to clarify ICAO regulations regarding the use of radar for providing navigation assistance to ensure controllers do not exceed their intended scope of service.