The Learjet Model 60 is the subject of a recent FAA Safety Alert for Operators (Safo) to maintain the correct tire pressures. FAA Flight Standards Service Safo 09012 recommends measuring cold tire pressure at the intervals recommended by the manufacturer.
The Safo was based on the results of the initial investigation of a Sept. 19, 2008, fatal accident in which a Learjet Model 60 departing Columbia Airport, S.C. overran the runway when the crew attempted to reject the takeoff. The two crewmembers and two of the four passengers were killed; the other two passengers suffered serious injuries. The aircraft was destroyed by extensive post-crash fire.
According to the FAA, the initial investigation revealed tire debris and portions of the airplane’s components on the runway. “It is possible that low tire pressure could have led to a tire failure,” the report states. “The average aircraft tire is composed of 50 percent rubber, 45 percent fabric and 5 percent steel. These tires are designed to carry heavy loads at high speeds. Problems caused by incorrect tire pressure can lead to catastrophic failure of the tire(s). Overinflation of a tire can cause uneven tread wear, reduced traction, make the tread more susceptible to cutting, and can increase the stress on aircraft wheels. Under-inflation of a tire can cause uneven tire wear and greatly increases stress and flex heating in the tire, which shortens tire life and can lead to tire blowouts.”
According to the Safo, pressure checks of tires are most accurate at ambient temperature when tires have been at rest for at least two hours.