AFTER THE WORST year ever for air crashes, any report of structural deficiencies found on a certain jumbo-jet model is likely to attract more than a little public attention. But there appears to be no cause for alarm in the lat announcement that the Federal Aviation Administration has ordered inspections of all Boeing 747s after finding cracks in the frames of four of the planes. The discovery and the order are examples of how proper maintenance and inspection procedures can detect aircraft wear and tear. Officials do not consider cracks in frames or in outer skins of planes unusual or necessarily dangerous.

The 747 has long been regarded as among the safest of airplanes -- although two were involved in catastrophic accidents last year. But neither the Air India crash in the North Atlantic nor a Japan Air Lines crash has been linked to the types of cracks that prompted the new FAA order. Court testimony in the Air India case, though not conclusive, has pointed to a bomb as probable cause. An improper repair to structural damage from an earlier incident has been pinpointed as the probable cause of the JAL crash.

Boeing has been manufacturing 747 jets since the '60s, and there are more than 600 of them in use around the world. The latest order -- an "airworthiness directive" of the sort issued routinely and almost daily by the FAA -- applies to the older planes in service and sets out a schedule for inspections. It came in response to routine tear-down inspections done by an airline that found cracks in three of its jets and reported this to the FAA. The airline's officials say they have since inspected 25 planes and found nothing else. A second airline turned up a fourth possible case after a notice from Boeing.

Information on inspection discoveries should be openly reported, shared and acted upon, as it was here. Experts note that air travel remains relatively safe. These procedures are a key reason.