What happened
On November 9, 2017, at Carrasco International Airport (SUMU) in Canelones, Uruguay, a maintenance worker was performing inflation procedures on the left nose wheel of a Bombardier CRJ200, registration CX-SDU. During the process, the tire exploded, causing the mechanic to sustain serious injuries. Because the aircraft had already been deplaned and had not yet been released for its next flight, the event was classified as an occupational accident rather than an aviation accident or serious incident.
The investigation
The CIAIA investigation, conducted with the assistance of a local company, focused on the equipment used during the inflation process. Investigators examined the pressure gauges and regulators involved in the nitrogen inflation. The investigation established that while the high-pressure gauge showed some reading errors and the regulator and high-pressure gauge were otherwise functional, the low-pressure gauge had been subjected to a pressure surge.
Findings
- The low-pressure gauge experienced a water hammer effect (pressure surge) that exceeded its maximum operational range.
- The primary cause of the tire burst was the opening of the high-pressure valve (connected to a nitrogen cylinder at 3000 PSI) while the regulator was still open, directing high-pressure gas directly into the tire.
Safety action
Following the incident, safety recommendations were issued to all maintenance personnel, ranging from management to line technicians, emphasizing the following:
- Strict adherence to the aircraft manufacturer's recommended procedures.
- Compliance with the manufacturer's instructions regarding all tools and equipment used during maintenance tasks.
- A commitment to continuous improvement in procedures regarding personal safety, teammate protection, and the care of tools and aircraft.