What happened
On December 6, 2003, an Airbus A319-112, registration OH-LVH, operated by Finnair, was taxiing to its docking station at Helsinki-Vantaa airport following a scheduled flight from Munich. As the aircraft approached the gate under the guidance of the Advanced Visual Docking Guidance System (APIS), a gate officer simultaneously began moving passenger bridge 24 using automatic controls.
The officer initiated the movement from what was assumed to be the bridge's base position. However, the bridge was not in the correct starting position and extended significantly further toward the approaching aircraft than programmed. The aircraft's left engine struck the passenger bridge while the APIS display still indicated approximately 1.2 meters of remaining taxiing distance.
The investigation
The investigation focused on the technical performance of the bridge's automatic control system and the operational procedures at the airport. Investigators examined the APIS software logic and the physical positioning of the bridge. It was discovered that the bridge had experienced a "telescope max movement" malfunction multiple times on the same day, yet it had not been removed from service.
Technical analysis revealed that the bridge's automatic driving program logic was unable to identify or signal a failure in longitudinal control. This allowed the bridge to extend to its maximum position, roughly 4.2 meters beyond its intended programmed stopping point. Furthermore, the investigation found that a previously granted regulatory exemption regarding safety distances had not been fully implemented, specifically regarding the requirement for visual docking aids to only provide guidance when the bridge is in its base position.
Findings
- The primary cause was a malfunction in the automatic control system that caused the passenger bridge to extend past its correct holding position.
- Inconsistent operational standards had developed, where daily practices deviated from official training procedures.
- There were significant deficiencies in the training of bridge operators and the personnel responsible for inspecting malfunctions and identifying safety risks.
- The automation logic failed to detect and communicate the error in the bridge's longitudinal positioning.
- Organizational oversight was lacking, as the operating procedures and instructions for bridge 24 had not been audited by the responsible authorities.
- A latent risk existed because the docking position for short-fuselage Airbus aircraft was situated such that a fully extended bridge could reach the engine.