Japan Air System grounds MD 81 and MD 87 aircraft

Japan Air System (JAS), a member of the JAL Group, is inspecting the engines of aircraft in its two-engine MD81 and MD87 domestic fleet for cracks in a section of the high-pressure compressor.

The checks of the U.S. made Pratt and Whitney JT8D-217 series engines will take a few days and during that time aircraft will be grounded until they have passed inspection.

As a result on Monday January 19, about 120 JAS domestic flights were cancelled, affecting 7,000 passengers. (JAS usually operates 390 domestic flights per day). The airline stated that any future flight cancellations will be decided at a later stage.

After experiencing engine problems in an aircraft on January 6 at Fukuoka, and at Kagoshima in a similar aircraft on January 7, JAS had the engines involved inspected by the manufacturers, Pratt & Whitney, at their technical center in Christchurch, New Zealand. This inspection found damage in the stator sections of the high-pressure compressors in the engines of both aircraft.

In view of the similarity of the cases, JAS decided to inspect the engines of all MD81 and MD87 aircraft and this is now taking place. As of 0800 hours January 19 a total six aircraft have been checked and cracks found in engines of five. An additional 19 aircraft have been grounded pending the completion of the inspections. JAS currently has 25 of the type in service - 17 MD81s and 8 MD87s.

The unscheduled inspections require the use of a special optical instrument called a borescope that allows technicians to make an internal examination of the engine without dismantling it. Manufacturers or airline maintenance engineers usually make borescope checks during scheduled engine maintenance checks and overhauls.

The period of inspection will be about three days. The JAS MD81 and MD87 aircraft are dispersed at eight airports in Japan.