NATION

RKO General Inc., a New York-based broadcasting and entertainment company, on Monday announced three major promotions at its RKO Pictures Inc. subsidiary. C. Robert Manby, president of the unit since 1977, has been promoted to chairman of RKO Pictures and will oversee long-range planning and acquisitions in co-production and programming, the company said.

Succeeding Manby, 65, as president of the pictures unit, also based in New York, is Mark Seiler, 37, who previously was president of Century City-based RKO Film Group. Seiler will operate out of New York and will be responsible for RKO Pictures and its four divisions--RKO Film Group, RKO HomeVideo, RKO Worldwide Television Sales and RKO Tape. Gerald Offsay, 31, will succeed Seiler as president of RKO Film Group.

Forstmann Little & Co., which Monday concluded its $400-million purchase of 12 industrial companies from ITT Corp., named Richard W. Vieser president and chief executive of FL Industries, a newly formed unit comprising the 12 firms. Vieser is the former president of McGraw-Edison Co., which itself was the target of an unsuccessful takeover by Forstmann Little. FL Industries will be based in Livingston, N.J.

ITT had announced an agreement to sell the 12 companies to Forstmann Little in April. The move is part of ITT’s plan to divest about $1.7 billion worth of assets in order to streamline the company.

LOS ANGELES COUNTY

Chief Financial Officer Richard Van Wagenen has been named to the additional post of senior vice president of Knudsen Foods Inc., Los Angeles. Knudsen, one of the nation’s largest dairy products companies, is a unit of Winn Enterprises, where Van Wagenen is also vice president and chief financial officer.

Steven C. Jackson has been appointed first vice president and manager of the syndicate department for Bateman Eichler, Hill Richards Inc., a major regional brokerage firm based in Los Angeles.

WORLD

London-based Thorn EMI, plagued by troubles affecting the entire British electronics industry, announced that its chairman and chief executive, Peter Laister, has resigned after 14 months on the job.

Thorn EMI has had problems with its consumer electronics operations and semiconductor manufacturing unit, and on Monday it forecast a steep decline in profits for the current fiscal year ending Friday.