UPDATE 1-Boeing engineer says confident 787 safe, no comment on probe length

DUBLIN, Jan 23 (Reuters) - Boeing Co apologized to airlines on Wednesday for disruptions caused by the grounding of its 787 Dreamliner fleet and pledged to restore confidence in its newest passenger jet following a series of incidents that led to a U.S. safety investigation and flight ban.

Mike Sinnett, chief project engineer for the Boeing 787 program, said the company remained confident in the safety of the plane, which was grounded worldwide by regulators last week over potential fire risk following two incidents involving its lithium-ion batteries.

Sinnett was speaking to an aviation conference in Dublin, which was closed to the media. A recording of his remarks was supplied to Reuters.

"I can't really say anything about the timeframe of the investigation. The NTSB (National Transportation Safety Board) is really the only authorized authority in the U.S. to talk about this investigation and they made some recent statements, but I can't speculate on timeframe," Sinnett said.

"Our commitment to our customers remains that we'll resolve the issue as quickly as can and reduce as much as possible amount of disruption," he added.