What happened
On June 13, 1998, at approximately 14:19, a mid-air collision occurred at Hilversum airport involving two light aircraft. The first aircraft, a Cessna 152 with registration PH-CBA, was conducting a local instructional flight. During this flight, the crew was practicing a simulated emergency landing. This maneuver involved flying extremely low and short circuits, significantly below the standard 700-foot circuit altitude.
Simultually, a M.S. Rally 150ST, registration PH-DBX, was performing a standard private flight and was on its final approach to runway 18. As the Cessna 152 executed a steep, high-bank turn to intercept the runway, it descended from the left rear of the PH-DBX. The collision occurred at an altitude of approximately 30 meters, roughly 50 meters before the airfield boundary. Both aircraft lost control following the impact and crashed, resulting in the destruction of both airframes. The collision caused one serious injury and one light injury in the Cessna 152, while the PH-DBX sustained one serious injury and one light injury among its occupants.
The investigation
The investigation examined the flight paths, weather conditions, and cockpit communications. It was established that the weather was clear with stable air, and the technical condition of both aircraft was airworthy. Investigators looked into the validity of a radio announcement regarding the simulated emergency, but found no evidence that the pilot of the PH-CBA had actually broadcast a warning to other traffic, despite the instructor's claim.
Findings
- The instructor in the Cessna 152 deviated from standard circuit procedures by flying much lower and tighter turns than prescribed.
- The simulated emergency landing was initiated from a position and altitude that lacked realistic training value and introduced unnecessary risk.
- The high-bank maneuver required to intercept the runway prevented the instructor from scanning for other traffic.
- The failure to effectively apply the 'see and avoid' principle by both pilots was the primary cause of the collision.
- While the PH-DBX was focused on its landing, the pilot failed to notice the Cessna 152 even though it should have been visible during the final approach.
Safety action
Following the investigation, it was suggested that the Dutch aviation authorities consider implementing stricter regulations regarding how and under what conditions simulated emergency landings should be performed at uncontrolled airfields. Additionally, there was a recommendation to promote the use of onboard radios for position reporting at uncontrolled airports to improve situational awareness.