Some Chinese aviation safety experts have opined that there may be something wrong with the design of the Boeing 737, and that the latest explosion of a Boeing 737-800 plane owned by China Airlines (CAL) at Okinawa might have been caused by problematic design.

The experts, who declined to be identified, cite an internal Boeing SRP document indicating that if the fuel tanks near the wings were pierced, the fuel would leak profusely. The experts said such a situation is quite dangerous and said it may be caused by an inappropriate mechanical design.

CAL''s Boeing 737-800 jet burst into a ball of fire and broke into three sections after landing at Naha Airport in Okinawa, Japan on 20 August. All 165 people aboard the jet, including the eight-member crew, managed to escape safely. Initial findings showed that a loose bolt on the right wing slat fell off and pierced the fuel tank, causing a fuel leak that led to the fire and explosion.

Local aviation safety experts said that there were five cases of similar bolt problems found in Boeing 737s, including the latest one facing CAL. They said that a Japanese airline recently reported to the Japanese aviation authorities a similar bolt problem on the left wing of one of its Boeing 737-700 passenger jets.

A week ago, the US Federal Aviation Administration (FAA) FAA urged visual checks on loose bolts in all Boeing 737 series within 10 days, in response to reports of 23 cases in which bolts on the wing slats of Boeing 737 series planes were found to have worked loose. One bolt was reported to have damaged the fuel tank of a plane owned by an unspecified airline

CAL had already completed thorough checks on eight Boeing 737-800 passenger jets by Sunday 2 September, and was scheduled to finish inspections on its remaining five such planes before 7 September, in line with an instruction issued by Billy K.C. Chang, director general of the Civil Aeronautics Administrative (CAA) under the Ministry of Transportation and Communications.