The country's three major airlines will jointly conduct demonstration flights next month to show that airplanes will not be threatened by the Year 2000 computer problem, industry sources said Friday.

Japan Airlines, All Nippon Airways and Japan Air System plan to carry out the flights Sept. 13.

Although details, such as the routes and number of flights, have not been decided, they will be carried out separately from the normal flight schedule and carry no ordinary passengers, the sources said.

The Y2K problem arises in older computers, chips, programs and software that record years by only the last two digits rather than all four digits. If their programming remains uncorrected, computers may mistake 2000 as 1900, which could cause errors or system failures on Jan. 1.

For the demonstration flights, the carriers will configure the dates in the airplane computer systems to Dec. 31 and Jan. 1 to simulate the critical time during which the Y2K problem is expected to strike.

The carriers hope the demonstration flights will wipe out people's concerns ahead of the New Year's reservation season.

The plan for the flights was triggered when the country's major travel agencies decided to take caution in promoting travel packages that could be affected by the Y2K problem.

Japan Travel Bureau decided not to conduct package tours in which customers would fly at midnight Dec. 31 local time and Greenwich Mean Time to avoid potential troubles.