Mexicana Crash Blamed on Explosion of Overheated Tire

A fire started by the explosion of an overheated tire shortly after takeoff caused the March crash of a Mexicana Airlines jet that killed 166, Mexican aviation authorities said Thursday.

The disaster took the lives of 157 passengers and nine crew members when the Boeing 727 went down in mountainous terrain northwest of Mexico City on March 31. The official report from Mexico’s Civil Aeronautics Agency stressed that “there exists no evidence at all of the presence of an explosive device.”

Speculation that a bomb might have caused the calamity grew from stories that at least one explosion preceded the crash. Later, obscure terrorist groups in the Middle East claimed responsibility for bringing down the plane, and government-owned Mexicana issued strict security guidelines aimed at assuring that no bombs could be smuggled aboard its jets.

The Thursday report, which followed six weeks of investigation and official silence here, described a complex chain of events that occurred when a tire in the jet’s left landing gear overheated and burst, 15 minutes after takeoff.

Overheated wheel equipment, including brakes and mountings, “weakened the resistance of materials and increased the internal pressure of the tires,” the report said. There was no explanation for the excessive heat.

The tire’s explosion in turn ruptured several ducts, including some that carry fuel, water, electricity and air, the report said. Hot air released from the ducts ignited fuel, setting off a fire that “melted the structure of the fuselage.” The tail eventually gave way, and the pilot lost control of the craft before he could reach the nearest airport.

With the bomb reports apparently put to rest, attention may turn to maintenance questions at Mexicana. After the crash, mechanics union members claimed that aircraft maintenance had been reduced by managers. Legislators blamed budget cutbacks for reduced safety, not only on government-owned transport but also in factories.

Mexicana’s director of flight safety was quick to counter the complaints. “It is impossible that a plane would take off in bad maintenance condition,” safety chief Amadeo Castro asserted.