What happened
On the evening of September 15, 1995, a serious flight safety incident occurred in the vicinity of Helsinki-Vantaa Airport involving two aircraft. A Saab 340 B, registration OH-FAH, was performing a scheduled departure from runway 33, bound for Varkaus and Savolinna. Simultaneously, a Piper PA-28R-200 "Cherokee Arrow", registration OH-PJX, was operating under visual flight rules (VFR) and had reported its intention to join the downwind for runway 04.
As the Saab 340 B climbed out from runway 33, it passed in close proximity to the Piper. The aircraft passed approximately 800 meters in front of and above the Piper, with a vertical separation of roughly 700 feet. The lateral distance was estimated to be only a few hundred meters at the closest point, as the Piper was positioned in the aircraft's lower blind spot during the pass. While the pilot of OH-FAH observed the other aircraft and adjusted the climb angle to ensure clearance, the encounter constituted a significant loss of separation.
The investigation
The investigation examined the air traffic control (ATC) procedures, the experience levels of the personnel involved, and the use of intersecting runways. Investigators reviewed radio communications, which confirmed that the controller had cleared the Piper to join the downwind for runway 04 without implementing geographical separation via VAC chart methods. The investigation also looked into the controller's training and the workload at the tower during the event.
Findings
- The primary cause of the incident was a methodological error and an error in judgment by the air traffic controller, who failed to intervene sufficiently late regarding the arrival of aircraft on intersecting runways.
- The controller had very limited experience working at Helsinki-Vantaa at the time of the event.
- The controller was managing a near-maximum traffic load, which strained their operational capacity.
- The controller failed to use geographical separation techniques (VAC chart methods) to maintain distance between the aircraft until visual contact was established.
- The aircraft were operating in VMC conditions, and while the weather allowed for visual identification, the controller's failure to provide traffic information or separation instructions created the risk.
- The pilot of OH-FAH was the only party to formally report the safety hazard to the authorities.