What happened
On February 19, 2021, at approximately 22:10 local time, an ATR 72-2XXXXXXXXXXXXXXXX (registration EC-LYJ) operated by Swiftair experienced a tyre tread separation during its take-off roll on runway 24R at Palma de Mallorca Airport. The aircraft, performing a scheduled cargo flight from Ibiza with an intermediate stop in Palma, continued its flight to Madrid-Adolfo Suárez Airport without the crew noticing any unusual vibrations or changes in handling.
Upon arrival in Madrid, maintenance personnel identified damage to the left main landing gear, including a missing tread on wheel number 2, a damaged flexible hose, and damage to a landing gear door and inspection panel. While the operator initially coordinated with Madrid airport authorities to check for debris along the taxi route, no fragments were found there. However, the following morning, a different flight departing from Palma de Mallorca reported seeing tyre debris on runway 24R, which led to the discovery of the remaining 30% to 40% of the detached tread.
The investigation
The CIAIAC investigation focused on the physical condition of the tyre, the maintenance history, and the communication chain between the operator and the airport. Technical analysis of the recovered tyre fragments revealed a straight, one-layer cut in the tread, which was consistent with the tyre rolling over a foreign object. This puncture likely compromised the structural integrity of the tread, allowing centrifugal and radial forces to cause its eventual detachment.
Investigators also examined the runway inspection logs at Palma de Mallorca. Although scheduled inspections were conducted by experienced technicians both during the night and the following morning, the debris remained undetected. The investigation noted that the debris was similar in color to the asphalt, making visual detection extremely difficult under nighttime conditions.
Findings
- The primary cause of the incident was the perforation of the number 2 tyre by foreign object debris (FOD), which led to the detachment of the tread.
- The crew was unaware of the incident during the flight as no significant symptoms were perceptible during the take-off or subsequent flight.
- The operator failed to notify Palma de Mallorca Airport of the incident, resulting in the runway remaining contaminated with debris for approximately eight hours.
- Visual inspection methods used by airport personnel were insufficient to detect the debris due to the low contrast between the rubber and the runway surface and the limitations of nighttime visual monitoring.
Safety action
- REC08/24: It is recommended that AENA, as the provider of runway and apron services at Palma de Mallorca Airport, study ways to improve the detection of FOD on the runway.
- REC09/24: It is recommended that Swiftair implement measures to ensure all reported incidents are monitored through to their definitive closure.