What happened
On 04 July 2021, at approximately 16:30 local time, a Vulcanair P.68TC Observer, registration EC-KQV, was taxiing at Seville Airport (LEZL) to begin a fire-fighting coordination mission. While at the holding point for runway 27, the pilot heard a loud explosion, identifying that the right main landing gear tyre had burst. Shortly after, the pilot noticed a burning smell and observed that the right main gear tyre had caught fire.
The pilot immediately notified the control tower, secured the aircraft, and ordered an evacuation of the four occupants (one crew member and three passengers). The pilot attempted to suppress the fire using an onboard extinguisher until the airport rescue and fire fighting service arrived. All occupants were unharmed, and damage was limited to the right main gear tyre.
The investigation
The CIAIAC investigation focused on the origin of the tyre burst and the subsequent fire. Investigators examined the aircraft's maintenance history, noting that while the pilot performed a visual pre-flight inspection, the last recorded measurement of tyre pressure using a gauge had occurred 34 days prior. The investigation also reviewed the aircraft's braking system and the manufacturer's maintenance requirements.
Although the damaged tyre was not preserved for laboratory analysis, the investigation looked into potential heat sources. The manufacturer's manual and the tyre manufacturer's guidelines both emphasize the necessity of checking tyre pressure with a gauge and ensuring proper inflation to prevent overheating. Additionally, the operator's maintenance organization had recently performed inspections, but the investigation noted that the pilot's pre-flight check was limited to a visual assessment of inflation.
Findings
- The investigation could not definitively determine the exact cause of the tyre burst and fire.
- Inadequate tyre pressure or excess of braking during taxiing were identified as potential contributing factors.
- The aircraft operator had not measured the tyre pressure with a gauge for over a month prior to the incident.
- No external contaminants were found on the tyre or the taxiway surfaces.
Safety action
- The aircraft operator issued a Safety Bulletin (No. 05/2021) to its crews regarding the proper use of brakes in the Vulcanair fleet to prevent overheating and tyre blow-outs.
- The CIAIAC issued a recommendation (REC 11/22) to the operator to review and update its procedures to ensure tyre pressure measurements align with the aircraft manufacturer's requirements.