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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. |
