Ground Collision at Grenchen Regional Airport Involves Piper PA38-112 and Cessna C172 P (HB-PGU)

Incident Overview and Aircraft Details On 19 July 2003, at approximately 14:37 local time, a ground collision occurred at Grenchen Regional Airport in the Canton of Solothurn, Switzerland. The incident involved a Piper PA38-112 Tomahawk, registration HB-PGU, and a Cessna C172 P, registration HB-CJM. The Piper was operated by Maximair AG and was being used for flight training. The Cessna was privately owned and had just landed from Neuchâtel. ## Sequence of Events The Piper, piloted by a student pilot, was taxiing toward the runway 25 holding point after receiving clearance from air traffic control. The Cessna had landed on runway 07 and was taxiing to outdoor parking stand number 13, located in the ECHO taxiway area. Due to limited space and the presence of other parked aircraft, the Cessna could not be parked in its final position without parts of the aircraft protruding into the taxiway. The Cessna pilot assisted a passenger in disembarking and warned the passenger about the approaching Piper. The passenger moved toward the tail of the Cessna to assist with parking. The student pilot in the Piper attempted to avoid the passenger but struck him with the left wing. The two aircraft did not make contact. ## Injuries and Damage The passenger sustained serious internal injuries and was hospitalized for five days. The Piper sustained minor damage, specifically scratches on the left wing leading edge. No other persons were injured, and no third-party property damage was reported. ## Contributing Factors The investigation identified several factors that contributed to the accident. These included a lack of ground traffic coordination by the air traffic controller following a runway change, which was partly due to limited visibility from the control tower to outdoor stand number 13. The student pilot had an insufficient overall view during taxiing in an area with restricted parking conditions. The parking conditions at outdoor stand number 13 were described as cramped. Additionally, there was a lack of taxiway markings indicating a potential danger zone, and the Cessna pilot's supervision of the passenger was considered inadequate.