* Slashes profit outlook, third cut this year
* Expects FCF to be zero to negative $100 mln
* Shares fall 17 pct (Adds details on forecast, analyst comment)
June 11 (Reuters) - Car seats maker Adient Plc said on Monday Chief Executive Officer R. Bruce McDonald is stepping down and the company slashed its profit forecast for the third time this year, sending its shares tumbling 17 percent.
The company said former General Motors Co CEO Frederick Henderson will take over as interim chief, while McDonald will remain an adviser until Sept. 30.
The Michigan-headquartered company said its operating performance was running behind plan, and forecast free cash flow of up to negative $100 million for fiscal 2018.
It forecast adjusted EBITDA of about $1.25 billion for the year - well below its previous forecast of $1.40 billion-$1.45 billion.
Adient, which counts Ford Motor Co, General Motors Co and Tesla Motor Inc as customers, has been weighed down by higher costs at its seat structure and mechanisms business, which produces lightweight metal seat structures.
"It will likely be a multiyear journey to scale down the metals business, and it could take time to regain investors' trust," Morgan Stanley analyst Armintas Sinkevicius wrote in a note.
Adient has struggled to deliver consistent profits since it reported a $1.5 billion annual loss in 2016, and posted bigger-than-expected losses in the last two quarters.
Henderson was most recently chief executive at metallurgical coke producer SunCoke. He will leave his position on Adient's governance committee, but remain a board member.
Adient also named John Barth, its current lead director, as interim chairman.
The company separated from its parent Johnson Controls International Plc in Oct 2016.
Its shares fell as much as 17.43 percent to $47.05 in afternoon trading. (Reporting by Rachit Vats and Arunima Banerjee in Bengaluru Editing by Saumyadeb Chakrabarty)