However, San Francisco hospitals that dealt with the injured report an unusually high number of spinal injuries, the worst of which include crushed vertebrae and torn ligaments, testifying to the excessive lateral and vertical loads sustained during the accident. Although safety experts say assuming the crash position would have limited jolting to the spine, passengers appear to have received little or no warning of the impact. According to Randy Scarlett, board director of the California Brain Injury Association, “there were significant spinal cord and traumatic brain injuries with the first wave of patients. More subtle concussions and spinal cord injuries were in the second wave of those patients coming to San Francisco General [Hospital].” Scarlett expects that while 80% will fully recover, “20% will be affected for a significant time in their lives.”
Commenting on the safety implications, former NTSB Chairman Jim Hall questions the adequacy of the current 16g dynamic seat standard. “I believe that it is time to update aviation seat standards to take a stronger G force, especially in light of the many recent spinal and head injuries,” he says. The regulation requiring all newly developed transport aircraft to use 16g-capable seats was issued by the FAA in 1988, superseding rules at the time which mandated a static 9g standard with no occupant injury criteria.
From a systems perspective, investigators are focusing on the performance of the safety systems, door operation and emergency inflatable slide deployment. “We're taking a very close look at survival factor issues, including emergency doors and exits, and to see if there were any malfunctions,” says NTSB Chairman Deborah Hersman. The most serious of these occurred during the evacuation, when two cabin crew were “pinned” against the cabin side by escape slides that inflated inside the aircraft at Doors 1R and 2R. At least one flight attendant had to be rescued by the relief first officer who helped deflate the device. “We need to understand why that happened, and if it happened inadvertently,” says Hersman.