What happened
On the evening of 5 October 2012, an Airbus A320, registration 9V-TRG, was at Singapore Changi Airport's Bay E7. The aircraft had recently returned to the airport from Kuching due to inclement weather and was preparing for a rescheduled departure.
During the pre-departure phase, the flight crew requested that ground staff amend the flight's load document. To facilitate this, the passenger loading bridge (PLB) had to be re-docked to the aircraft. While the ground crew was performing this re-docking maneuver, the PLB made contact with the aircraft's fuselage. Upon inspecting the area following the movement, the ground crew discovered scratch marks and a skin puncture on the lower left side of the aircraft, approximately 1.2 meters behind the front cabin door.
The investigation
Investigators analyzed CCTV footage, which revealed that the PLB cab was not aligned parallel to the aircraft during the re-docking process. Instead, the cab was tilting at an angle, causing it to "rock" against the fuselage. A simulation using a mock-up fuselage confirmed that when the PLB is positioned at a non-parallel angle, the gap between the bridge and the aircraft becomes unsafe, and the metal edge of the PLB cab can strike the aircraft skin.
Metallurgical analysis of debris found on the PLB padding confirmed that fragments of 2024 aluminium alloy, matching the aircraft's skin, were present on the bridge. Furthermore, the investigation examined the functionality of the PLB's safety-interlocking sensors. It was determined that because the bridge was tilted, the sensor rod on the right side was too far from the fuselage to detect the approaching aircraft, rendering the safety mechanism ineffective at preventing the collision.