http://www.japantimes.co.jp/cgi-bin/...20051222a3.htm
JAL jet flew half year with engines on the wrong sides
Japan Airlines flew a Boeing jumbo jet for seven months without realizing its port and starboard outer engines had been switched to the wrong sides during maintenance in Singapore in February, airline officials admitted Wednesday.
Some of the engine components are required to be inspected every 650 flights, but the mistake resulted in one of the engines going through 850 flights before being examined.
Reversing engine locations causes air to flow toward the fuselage instead of away from it during reverse thrust when slowing after landing. However, it does not create any difference during normal thrust and thus poses no safety problems in flight, the officials said.
The Land, Infrastructure and Transport Ministry instructed the airline to take preventive measures anyway.
In February, JAL commissioned
ST Aviation Services Co. Pte Ltd. in Singapore to overhaul the four-engine Boeing 747. The plane resumed service in April.
It wasn't until a regular checkup in November that the engine switch was discovered, the carrier said.
JAL officials said they will revise in-house procedures to ensure plane inspections are conducted after outsourced maintenance work. The current policy only calls for document checks following maintenance.
The Japan Times: Dec. 22, 2005