Two airline fleets are checking the troubled Boeing 787 Dreamliner for new wiring problems unrelated to battery defects that plagued the aircraft earlier this year.
All Nippon Airways said the departure of a 787 plane was delayed over problem wiring for a system to put out engine fires.
ANA, which has 20 787s , said the flight from Tokyo to Frankfurt departed after the part was exchanged.
A spokeswoman said it found two similar problems while inspecting its other 787s.
Japan Airlines said a 787 headed to Helsinki returned for inspections, and its nine other 787s are being checked.
Dreamliner jets were grounded worldwide in January for lithium-ion batteries that overheated or caught fire. Flights resumed four months later after a revamped battery system was installed.