NTSB Factual Report

On July 23, 2008, approximately 2230 mountain daylight time, an Airbus Industrie A319-114, C-FYJP, registered to and operated by Air Canada and piloted by an airline transport certificated pilot, sustained minor damage when the right inboard tire failed during takeoff at Denver International Airport, Denver, Colorado. Visual meteorological conditions prevailed at the time of the incident. The scheduled international passenger flight was being conducted under the provisions of Title 14 Code of Federal Regulations (CFR) Part 129, and an instrument flight rules flight plan had been filed. There were no injuries to the two cockpit crewmembers, three flight attendants, and 94 passengers. The flight was originating at the time of the incident.

According to Air Canada, as the airplane accelerated for takeoff on runway 25, the captain detected a whistling noise and realized his side window was not secured. The takeoff was rejected and the airplane was taxied back. Before the second takeoff was initiated, the crew confirmed that all brake temperatures were below 300 degrees Celsius (C.). Takeoff was initated and gear retraction, which was delayed to allow the brakes to cool as a result of the previous rejected takeoff, was normal. When the flaps were retracted, an F-LOCKED message was received. Slats were retracted and flaps retracted to just short of the number 1 position. An emergency was declared. When the airplane was configured for landing, the following messages were illuminated: RIGHT UNLK ON PANEL; L/G SYS DISAGREE; L/G NOT DOWN. A go-around was executed. The crew then contacted the company's dispatch and maintenance departments. Air Canada's maintenance department informed the crew that if one GREEN triangle on the DOORS page was illuminated, then the right landing gear was effectively down and locked. A flaps 3 landing was made on runway 16R. Although the landing was said to be smooth, there was a noticeable vibration on the right side of the airplane. Minimal braking was used to slow the airplane on the 16,000-foot runway, and there was no difficulty maintaining runway centerline.

Post-incident inspection by FAA inspectors and Air Canada personnel revealed the right inboard tire (number 3) had failed. Cabin crew personnel and several passengers said they noticed a vibration when the airplane was rotated for liftoff. Runway inspection revealed rubber fragments on the right side of the runway approximately the 6,000-foot mark.

The failed tire was sent to Goodyear for examination and analysis. According to Goodyear’s report, tire construction consisted of six casing plies, eleven belts, and one retread ply. There was a sidewall circumferential casing break and a half dozen localized breaks. There was a 360-degree shoulder-to-shoulder tread separation. There was rubber bluing of the tread pieces, exposed casing surface, and beads, "indicating excessive heat." The exposed casing surface was worn "from continued rolling after the tread loss, especially in the shoulders due to pressure loss." Broken ply chords at the sidewall break showed evidence of "severe heat including reverted rubber, charred nylon, and rubber bluing." The liner was abraded from rolling while bottomed after the pressure loss.

Goodyear concluded that "the tire sustained a casing break, likely due to prior pressure loss, which led to complete pressure loss, severe stress on the tire, and the subsequent tread separation." The root cause of the casing break could not be determined. The rejected takeoff "would have generated extra heat in the tires, which would have been detrimental to the tire’s integrity, especially if it was combined with low inflation pressure before the second takeoff. This would have introduced additional heat which would have contributed to the casing break."

NTSB Probable Cause

Total failure of the right inboard tire. Contributing to this incident were the low pressure of the tire, and the high tire heat generated by the previous rejected takeoff.