All Nippon Airways Co. delayed a Wednesday flight from Tokyo's Haneda airport to Frankfurt for about 1 hour and 40 minutes due to a problem in the wiring of a fire extinguisher for an engine on one of its Boeing 787 Dreamliner twin-jets.

ANA found similar wiring problems in two other aircraft after checking all 20 of its Boeing 787s, while Japan Airlines Co. returned a Helsinki-bound Dreamliner to Narita for a check after receiving notification of the problem.

The problems were found in the control system of the fire extinguishers near the front cargo bay. If a fire were to occur in one of the jetliner's two engines, extinguishers may erroneously target the other engine, ANA said.

These problems were not related to the battery problem in January that triggered the worldwide Dreamliner grounding, the airline said.