What happened
On the night of 8 September 2020, during routine maintenance of approach lights at Birmingham Airport, a 2.2-metre A-frame step ladder fell from an airport engineering pickup truck onto Runway 33. The vehicle, identified as WV4, was transporting the ladder to the touchdown zone following maintenance tasks.
As the vehicle travelled along the runway, the ladder became unsecured and slid onto the pavement, coming to rest just to the right of the runway centreline. In the interval between the ladder falling and its discovery, three commercial aircraft landed on the runway. The first two aircraft, a Boeing 737-800 (EI-DPC) and another Boeing 737-800 (G-GDFR), both noted potential objects or markings in the touchdown zone but were uncertain of their nature. The third aircraft, a Boeing 7 .57-200 (G-OOBA), landed and subsequently alerted Air Traffic Control (ATC) that a ladder was visible on the runway. The ladder remained on the active surface for approximately 37 minutes before being recovered by the airport safety team.
The investigation
The AAIB investigation established that the ladder had been secured in the back of the pickup truck using an elastic bungee cord. While the technicians were performing maintenance, the vehicle accelerated through the touchdown zone, creating a snatch load that caused the bungee hook to open and the ladder to unfasten.
Investigators found that the use of a bungee cord was an inadequate method of restraint for the load. Although more robust equipment, such as ratchet straps, was available within the engineering facility, they were not being used for this task. Furthermore, the investigation noted that the tower controller's inquiry to the crew of G-OOBA—asking if they were "happy to continue"—was phrased in a way that did not explicitly warn of a potential hazard, which may have influenced the crew's decision to proceed with the landing.
Findings
- The ladder fell from the vehicle due to inadequate load security provided by an elastic bungee cord.
- The bungee cord's hook opened under the tension of the vehicle's acceleration, allowing the ladder to topple and slide onto the runway.
- The noise of aircraft tyres on the grooved runway surface likely masked the sound of the ladder hitting the ground.
- The first two aircraft did not identify the ladder as a hazard, likely perceiving it as runway paint or markings.
- The aircraft involved narrowly avoided a collision with the object due to the ladder's position relative to the landing gear track width.