What happened
On July 21, 2024, Max Air Limited flight NGL 1648 arrived at Lamido Aliyu Mustapha International Airport (DNYO) in Yola from Abuja. After disembarking passengers and conducting a walk-around inspection that included checking for foreign object debris (FOD) reported by the previous crew, the aircraft was prepared for its return flight to Abuja as NGL 1649.
At approximately 17:57 local time, the Boeing 737-300 with registration 5N-ADB began its takeoff roll on Runway 35. During acceleration, the crew noticed the auto-throttle disconnecting and experienced unusual airframe buffeting above 100 knots. A loud bang was followed by a cockpit warning indicating a disagreement with the right main landing gear position.
Recognizing the anomaly, the pilot flying retarded the thrust levers to initiate a rejected takeoff (RTO) at roughly 126 knots indicated airspeed. The aircraft decelerated using brakes and reverse thrust, coming to a complete stop 300 meters short of the runway threshold. Aerodrome Rescue and Fire Fighting Services responded, and all 119 occupants (6 crew and 113 passengers) disembarked safely via airstairs without any reported injuries.
The investigation
The Nigerian Safety Investigation Bureau (NSIB) arrived at the scene the following day to commence a preliminary investigation under ICAO Annex 13 standards. Investigators retrieved the Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) for analysis. Physical evidence on the runway included witness marks consistent with tire failures approximately 1,000 meters from the threshold.
Post-incident inspection of the aircraft revealed that Number 3 main wheel tire had failed and Number 4 tire had burst. Numbers 1 and 2 tires were deflated due to the stop. Additionally, brake assemblies on the left side showed signs of binding, and the right main landing gear shock strut door was broken. The runway surface was noted to be contaminated with rubberized deposits, though FOD had been cleared earlier in the day.
Findings
The NSIB preliminary report establishes several key facts regarding the incident:
- The flight crew held valid certifications and medical licenses appropriate for the operation.
- The aircraft possessed a valid Certificate of Airworthiness at the time of the event.
- The rejected takeoff was triggered by increased airframe vibrations, an audible bang, and the right main landing gear disagree indication.
- Physical examination confirmed that the failure of tire Number 3 and the bursting of tire Number 4 occurred during the high-speed portion of the takeoff roll.
- The aircraft stopped safely within the remaining runway distance, and the survival aspects were deemed adequate as deceleration forces remained within design limits.
Safety action
As this is a preliminary report, no final safety recommendations have been issued. However, the NSIB has identified further investigations required to determine the root cause of the tire failures and the condition of the runway surface at DNYO.