to dump fuel to reduce weight for an emergency landing. During that time, damage to the aircraft was assessed, and the injured were treated by doctors on the passenger list. After dumping fuel, the aircraft returned to the airport. Emergency services were deployed, and the plane landed on runway 28L. During landing, six tires on the under-wing landing gear failed. Reverse thrust functioned only on engine 4 and so the aircraft slowly veered to the right, off the runway, and came to a stop. The left under-wing landing gear caught fire, but the fire was extinguished by dirt once the plane veered off the runway. After stopping, the aircraft slowly tilted backwards because the body gear had been ripped off or disabled on takeoff. The aircraft came to rest on its tail with its nose elevated. Until the accident, it was not known that the 747 would tilt backwards without the support of the main body gear. Injuries There were no fatalities among the 218 passengers and crew aboard, but 2 passengers were seriously injured during the impact, and during the subsequent emergency evacuation, 27 more sustained injuries, 2 of them seriously. Rods of angle iron from the ALS structure penetrated the passenger compartment, injuring passengers in seats 47G (near-amputation of left leg below the knee) and 48G (severe laceration and crushing of left upper arm). After landing, the aircraft veered off the runway on its damaged landing gear and came to a halt. Evacuation commenced from the front because the evacuation order was not broadcast over the cabin address system (it was erroneously broadcast over the radio), the order being given by one of the flight crew exiting the cockpit and noticing that evacuation had not commenced. During that time, the aircraft settled aft, resting on its tail in a nose-up attitude. The four forward slides were unsafe for use because of the greater elevation and high winds. Most passengers evacuated from the rear six slides. Eight passengers using the forward slides sustained serious back injuries and were hospitalised. Other passengers suffered minor injuries such as abrasions and sprains. Investigation The accident was investigated by the National Transportation Safety Board (NTSB), which issued its final report on May 24, 1972. The NTSB found the probable cause of the accident: ...the pilot's use of incorrect takeoff reference speeds. This resulted from a series of irregularities involving: (1) the collection and