The chairman of the National Transportation Safety Board yesterday formally convened a detailed study of emergency air control measures adopted after the controllers strike, noting that to date the board has received "no substantial indication of safety deficiences" in the new system.

But in remarks to members of the team that will conduct the survey, chairmaqn James B. King said that unanswered questions about how the control system functions in the strikers' absence have helped create "an element of uncertqainty" about safety among the public.

Kin said the investigation would include spot checks at control facilities around the country. The task is expected to tqake about two months, he said, although any major safety hazards that are found would be reported immediately to the board.

Board personnel have informally monitored the system since the strike began Aug. 3, King said. Pilots they had interviewed said "just about universally" that acceptable standards of safety were being met, according to King.

The board's study is one of three federal inquiries into the control system announced last week. The Federal Aviation Administration commissioned one study by the non-profit Flight Safety Foundation and another by a citizens commission on working conditions at traffic facilities.

The FAA has begun dismissal proceedings against more than 11,000 striking controllers. With air traffic reduced, the control boards are being staffed by non-striking controllers, supervisors and military controllers on loan to FAA.

The Professional Air Traffic Controllers Organization, the striking union, has charged that these people are overworked and often unqualified and that "near misses" in the air have increased. The FAA contends that air travel is as safe, if not safer, than it was before the strike.

Yesterday King said he was particularly interested in the FAA's methods of assigning workloads to individual controllers. He told the staff members: " . . . You will be addressing how the FAA monitors fatigue, effectiveness, short-term burn-out and other health impacts of the work-load on the controllers which might pose a threat to safety."

Other focal points would include how the FAA plans to recruit and train a new corps of controllers and keep the system staffed in the interim, how it assigns staff members to sectors with heavy traffic, and the qualifications of persons operating the system.

The board is an independent body set up to conduct impartial investigations of accidents and potential threats to safety. It can make recommendations to other government agencies but has no direct enforcement powers.