Honolulu hospitals reported this morning that only 3 of the 23 people injured remained hospitalized; all were in either good or fair condition. They included one flight attendant, who was not identified. Three other attendants were among the injured. 247 Continue Trip

Many of the injuries came in the first explosive rush of air when overhead bins fell apart and baggage flew through the cabin, or, after landing, in the rush to evacuate the plane's two passenger levels.

Several of the injured passengers had been in the 46-seat business class section on the main deck where several seats along the right window in rows 9 to 12 were missing. The torn section of fuselage extended up to the window line of the small upper deck where, just behind the cockpit, there were 16 more business-class seats. The plane also held 320 coach seats at the rear of the main deck, behind the business class section, and 18 first-class seats on the main deck ahead of the business section. One first-class seat, 4 business-class seats and 59 coach seats were vacant.

Late Friday 247 of the original 336 passengers continued their journey to Auckland, New Zealand, and Sydney, Australia, aboard another Boeing 747 brought to Honolulu by the airline.

The passengers left even before 14 investigators from the National Transportation Safety Board and the 3 others from the Federal Aviation Administration arrived from Washington. The investigators' flight landed here late Friday. Interviews With Pilots

This morning the investigators joined representatives from Boeing; Pratt & Whitney, the maker of the four engines; and pilots', mechanics' and attendants' unions to interview the crew and begin a painstaking examination of the crippled jet, with special attention to the gaping hole on the right side. The disabled jet was towed to Hickam Air Force Base next to the airport and parked on the tarmac.

Although they did not rule out other scenarios, investigators focused their initial inquiries on possible structural or mechanical failure of the cargo door or its locking mechanism.