The recent air tragedy over Hawaii that claimed nine lives when the fuselage of a United Airlines Boeing 747 ripped open leaves little doubt about the need for more strict monitoring and maintenance of aircraft.

Although the precise cause of the problem is yet to be determined, experts believe structural failure or a faulty door latch was involved. The accident follows other recent mishaps in which aging aircraft were involved. United's 747 had been in service since 1970.If the experts' hunches are right - that structural failure in an aging aircraft is involved - debate is certain to intensify over the adequacy of the Federal Aviation Administration's inspection program.

Aircraft manufacturers and the airlines insist that with proper maintenance and inspections, a plane should be able to fly indefinitely. But some safety experts dispute that, and they are critical of government efforts to monitor problems in a commercial fleet whose planes average 12.6 years of service.

"If we were doing enough and doing it right, we wouldn't have these things coming apart in the sky, said Wayne Williams, president of the National Transportation Safety Association, a private air safety organization.

"Aging aircraft is the most serious problem we have in aviation today," said John Galipault, president of the Aviation Safety Institute, a private watchdog group.

It's not as if a need for better maintenance and monitoring was something new.

At least three years ago, Congress and the Reagan administration recognized that the government's system of airplane inspections was so understaffed and poorly run that it was contributing to unsafe conditions in the skies.

That being the case, should it be chalked up to only luck that in the thousands of air trips since then, more tragedies like that over Hawaii have not occurred?