The plane remained immobilized for five and a half hours on the Orio al Serio runway (Italy), with the landing gear seriously damaged, the tires destroyed and a footprint of 450 meters on the asphalt. Almost two years after that accident, which occurred on October 1, 2024, the Italian National Agency for Flight Safety has published its final report and indicates the locking of the wheels during landing as the cause.
The accident
It is 7:55 and the Boeing 737 Max of Ryanair flight FR 846, from Barcelona-El Prat, with 162 passengers and six crew members on board, begins landing. The plane has just touched down when the control tower observes fire. The pilots hear a pop in the left rear and then others in the right. The device completes the landing maneuver without any setbacks even though the two right tires on the rear axle have completely disappeared. The passengers do not notice anything and there are no injuries. The left engine is 25 centimeters from the ground, although at no time does it touch the track.
At 8:40, passengers are disembarked and transferred to the terminal. Airport activity is paralyzed. For that day, 308 operations were planned between departures and arrivals. At 1:30 p.m., the plane is transferred to the Ryanair hangar and maintenance technicians from the Seas company begin repairs. Inside the terminal, absolute chaos reigns, with passengers whose flights have been canceled trying to figure out what to do. Arrivals are diverted to Verona or Malpensa, alternative buses make 22 routes and 120 people are mobilized to deal with the emergency, including staff from Orio, Enac and external companies. The airport reopens at 7:39 p.m. 129 flights are canceled and some 21,000 passengers are affected.
The checks
An Ansv investigation team immediately travels to the site to carry out technical inspections of the runway and the plane. Flight recorders are recovered to analyze landing parameters and cockpit conversations.
This is the dialogue maintained during the minutes of landing.
At 7:55:31, control tower (Tdc) "Okay, we have seen fire in the engines. Have you done a backtrack [maneuver in which a plane rolls along the runway in the opposite direction to that of takeoff or landing]?"
Pilot. "Negative, we have problems with the brakes." Eleven seconds later he adds "Torre, what do you see, please?"
Tdc. "I've seen something like an explosion and fire. It seems to be coming from the engine, but I'm not sure."
Pilot, 28 seconds later. "We need assistance. At the moment we cannot move under our own power."
Tdc. "Yes, no problem. Hold position, the firefighters are coming." Thirty-three seconds later he adds "Looking at the track I see tire remains, I think about 220 meters behind you. Maybe it was a tire explosion."
Pilot. "Yes, thanks".
The technicians analyzed the condition of the plane and its onboard equipment, the interventions carried out during the hours prior to takeoff from Spain and the communications maintained in the cabin.
The conclusions
The entire investigation revolves around the anti-skid, the system that prevents the landing gear wheels from skidding on the asphalt during landing. The Ryanair locked its wheels during landing because it was flying with the system deactivated and the crew braked before the plane had completely stabilized on the runway.
Before taking off from Spain, the technicians had detected a problem in the anti-skid and, to allow the return flight, the two channels of the system were deactivated, despite the fact that the fault signals only pointed to a problem in the internal channel. The investigation has discovered a contradiction between the maintenance manual and the minimum equipment list. This led technicians to disconnect the entire system instead of isolating just the faulty part.
During contact with the Orio runway, the pilots involuntarily pressed the brake pedals before the plane was completely on the ground. Since the protection was not active, the brake calipers immediately locked the wheels. In addition, the spoilers - the air brakes located on the wings - were not manually deployed in time, which delayed the transfer of the plane's weight to wheels that were already completely blocked. As a result, the tires stopped spinning and began to drag on the asphalt.
