The experts, who declined to be identified, cited an internal SRP document of the U.S.-based Boeing Inc. as indicating that if the fuel tanks near wings are pierced, the fuel oil would leak profusely. The document said such a situation is quite dangerous and attributed to inappropriate mechanical designs.

CAL's Boeing 737-800 jet burst into a ball of fire and exploded into three sections after landing at Naha Airport in Okinawa, Japan on August 20. 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 then pierced the fuel tank, causing 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.

Meanwhile, they said that a Japanese airlines recently reported to Japanese aviation authorities a similar bolt problem on the left wing of one of its Boeing 737-700 passenger jet.

Just one week ago, the U.S. Federal Aviation Administration (FAA) FAA urged visual checks on loose bolts on all Boeing 737 series within 10 days, in response reports of 23 cases in which bolts on the wing slats of Boeing 737 series were found to have come loose, and one bolt even damaged the fuel tank of the jet owned by an unspecified airline

In related news, the CAL already completed thorough checks on eight Boeing 737-800 passenger jets as of yesterday, and is scheduled to finish inspections on its remaining five such planes before Sept. 7, 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.