NOW THAT ALL of the DCIOs are on the ground, the job of those worrying about the planes' future is not just to get them flying again. Public confidence in the safety of the planes was badly shaken even before they were grounded indefinitely, and public confidence in the whole air safety program has been weakend. The Federal Aviation Administration, the McDonnell Douglas Corp. and the airlines must rebuild that confidence, in addition to repairing whatever faults are found in the design or maintenance of the DC10s.

To put it midly, this will not be easy. The now-they're-flying, now-they're-not routine of recent days damaged the FAA's reputation for worrying more about safety than the economic welfare of the airline industry. And the public argument between McDonnell Douglas and American Airlines about who did or didn't do what in the maintenance program has not helped. While that exchange has relevance to who may be liable in the damage suits resulting from the Chicago accident, it suggests to the public that both the manufacturer of the DC10 and one of its major customers are more interested in passing the buck than solving the problem.

Enough questions have been raised about the DC10 for the FAA to require a full recertification of all aspects of the airplane before it is permitted to carry passengers again. It is not enough to discover and correct what may be wrong with the engine mountings and the hydraulic systems. Before the FAA permits the plane to fly, it should be able to tell the public it has reexamined the data from the original certification tests, compared it with the many reports in its files on the operating problems the plane has experienced, and is convinced that the plane is totally safe.

That will be expensive for many airlines, which are now stuck with hundreds of millions of dollars worth of idle equipment. But in the long run it may be the cheapest solution - cheaper than putting the planes back in the air prematurely. With such assurance from the FAA, the public may begin to feel comfortable with the DC10 again. Without it, the DC10s could become a real liability to the airlines that own them and an economic bonanza to the airlines that can advertise flights on other kinds of aircrafts.

But dealing with the DC10s is only part of the FAA's problem. Despite the remarkable safety record of the airlines, recent newspaper and magazine stories on the history of the DC10 have raised questions about the adequacy of all the FAA's testing, certification and inspection procedures. These are not likely to go away until the FAA reexamines all its operations and restudies the other planes in the air with special reference to what it is learning about the DC10.

This is a big job for the FAA and its administrator, Langhorne Bond. But in his two years in this job, Mr. Bond has established a reputation as a man who does not duck difficult problems and who is willing to take new steps to improve air safety. This time part of his task is to take steps that will not only improve air safety but also reassure the public about how safe it is to fly.