More than 700 Boeing jetliners operated by every major U.S. airline must undergo a comprehensive inspection for cross-wiring and cross-plumbing in their safety systems, after problems were discovered in 17 aircraft.

The Federal Aviation Administration, in issuing the "airworthiness directive" late Tuesday, also noted that Boeing is studying its design, production procedures and testing of airliner emergency systems to see if changes are needed.The newly ordered tests are not expected to disrupt airline schedules and can be completed anytime over the next 31/2 weeks while the airliners are undergoing routine maintenance.

The order affects 741 newer jetliners flown by U.S. carriers. It applies to all Boeing 737s, 747s, 757s and 767s built after Dec. 31, 1980. Most foreign airlines using the planes also are expected to comply.

No accident or emergency has resulted from faulty wiring or plumbing found in airliners in recent weeks after the FAA issued limited directives applying to only specific systems in certain types of aircraft.

But the foulups, including cross-wiring, cross-plumbing, incomplete wiring and other problems, could have caused shutdown of the wrong engine in the event of fire, activation of the wrong sprinkling system in a cargo hold or lack of any response in emergency systems.