Chang Kuo-Wei, also a pilot for a carrier he had led since 2013, had just flown an EVA jet to Singapore when he was ousted at a March 11 board meeting called by his three older brothers, according to an EVA spokesman and Chang's lawyer. No reason for the move was given when EVA announced it later that day.

At stake for the Chang family is control of shipping and transport giant Evergreen Group, whose founder and patriarch Chang Yung-fa died in January. For institutions invested in EVA, like the Vanguard Group and BlackRock, the question is simpler: will the $2 billion airline stick to long-haul expansion plans and record new jet orders mapped out by its former boss?

"Investing in a company is investing in its leader," said a fund manager at one of EVA's top 30 investors who declined to be identified by name. "You buy Hon Hai Precision shares because of (Foxconn founder) Terry Gou. You buy EVA stocks because of Chang Kuo-wei."

Widely referred to as 'KW', Chang Kuo-Wei wasn't available for comment. His lawyer, Daniel Song, said the 46-year-old who steered the carrier's recent strategy - including intensifying a livery and design tie-up with the 'Hello Kitty' cartoon character - is now "taking a rest" at an undisclosed location.

Chang has no plans to seek reinstatement at the carrier, in which he has a personal stake of about 12 percent, the lawyer said, but is taking legal action over broader issues surrounding the Chang family fortune. EVA accounts for the bulk of Evergreen's profit amid a downturn in the shipping industry.

Officials at EVA and Evergreen said the other Chang brothers could not be reached, and would not want to comment on family business.

After shedding as much as 5 percent after the departure, shares in the firm, in which Chang and his brothers own 44.5 percent in total, are now just 2 percent below their March 11 close as EVA pledges continuity.

"EVA has been around for 25 years," said EVA spokesman Golden Kou. "What it has accomplished and its employees have delivered will not be affected."

'HELLO KITTY' BOOST

Still, some investors said new chairman Steve Lin, a company veteran, and the Chang family will need to reassure the market.

"Foreign investors are worried," said the fund manager at a top-30 EVA investor. "They are concerned that EVA without Chang (Kuo-Wei) would not be able to go further than it has achieved."

Institutional investors hold just over 10 percent of EVA stock, according to Thomson Reuters data. BlackRock declined to comment while Vanguard could not be reached for comment.

Since Chang Yung-fa's death, his four sons have been at loggerheads. The three eldest brothers, sons of the patriarch's first wife, dispute a will that Chang Kuo-Wei - son of his father's second wife - said last month gives him Chang Yung-fa's entire fortune, including cash, properties and shares.

Beyond EVA, the group includes Asia's largest container fleet through Evergreen Marine, catering businesses, air cargo operations and a hotel chain. Domestic media estimate Evergreen's assets at more than T$400 billion ($12 billion) in total.

With Chang Kuo-Wei at the helm, EVA has risen to become a major player in the growing trans-Pacific market in recent years, using Taipei as a hub for passengers traveling from Southeast Asia and China to destinations like Los Angeles and Houston. The tieup with Japan's Sanrio Corp's 'Hello Kitty' character helped spread its brand internationally.

It joined the Star Alliance group of carriers in 2013 and placed an $8 billion order, its biggest ever, for 26 Boeing widebody jets in 2015.

One of the incoming chairman's first tasks in public is likely to be presenting the airline's fourth-quarter 2015 results, due within the next few weeks. Beyond the numbers, EVA can expect questions from shareholders on the leadership shake-up and plans in the post-'KW' era.

"Their new management has not told us what they are going to do," said an official at one of the company's top 20 investors, speaking on condition of anonymity. He said he would be watching closely for any potential threat to EVA's "impressive performance".

(Additional reporting by Siva Govindasamy in SINGAPORE; Editing by Clara Ferreira Marques and Kenneth Maxwell)

By Faith Hung