What happened
On November 21, 2021, at approximately 12:25 local time, a ground incident occurred at Stand D8 of Nnamdi Azikiwe International Airport in Abuja. The event involved Max Air Limited aircraft 5N-DAB, a Boeing 737-300, and a lavatory service truck operated by Skyway Aviation Handling Company Plc (SAHCO).
The Boeing 737-300, registration 5N-DAB, had completed its third flight sector of the day and was parked at Stand D8 while boarding passengers for its fourth sector to Maiduguri. During this phase, the flight crew requested lavatory servicing for the aircraft. At the time of the request, an SAHCO Ground Support Equipment (GSE) driver was operating a conveyor belt truck for a different aircraft. He was instructed to abandon that task and attend to 5N-DAB.
The driver positioned the lavatory service truck near the aircraft with the assistance of a marshaller and applied wheel chocks. However, he found that his reach to the aircraft's lavatory drain valve was insufficient and asked the marshaller to guide him closer. The marshaller removed the chock from behind the truck's tire. According to investigation findings, the driver then reversed the vehicle abruptly without waiting for explicit clearance or establishing communication with the marshaller.
The truck accelerated unexpectedly, striking the tail section of 5N-DAB. It continued moving underneath the aircraft's rear fuselage before colliding with a catering service truck parked on the left side. The impact caused significant vibration and noise, prompting the pilot to halt boarding and disembark passengers who were already onboard. No injuries were reported among the crew, passengers, or ground staff.
The investigation
The Nigerian Safety Investigation Bureau (NSIB) conducted a final inquiry into the incident. Investigators examined the physical damage to the aircraft, which included three holes in the unpressurized aft fuselage area, dents on the pressure bulkhead, and a broken rear outflow valve. The lavatory service truck also suffered substantial damage.
The investigation focused on operational procedures, ramp coordination, and human factors. It was established that the GSE driver held valid licenses and training but was distracted by having to switch tasks mid-operation. There was no standard procedure for transferring unfinished duties to another operator, leading to time pressure and haste. Furthermore, the initial positioning of the truck was inaccurate, necessitating the risky repositioning maneuver.
Findings
The primary cause of the incident was the GSE driver mistakenly stepping on the throttle pedal instead of the brake pedal while reversing, resulting in the uncontrolled movement of the vehicle into the parked aircraft. Contributing factors included inadequate ramp supervision, insufficient manpower at the ramp leading to staff being pulled from other tasks, and a lack of standardized procedures for task handover. The driver also failed to maintain communication with the marshaller during the repositioning attempt.
Safety action
NSIB issued several safety recommendations to SAHCO Plc and relevant stakeholders. These include ensuring strict adherence to Standard Operating Procedures regarding equipment operation and task continuity, maintaining adequate manpower levels at the ramp to handle simultaneous operations, and improving coordination and supervision of ground handling activities. Additionally, immediate recommendations were made regarding the preservation of accident scenes in compliance with civil aviation regulations.