At about 12:00 Alaska time, a Cessna 172S was damaged during an emergency landing at Quartz Creek Airport. The pilot and one passenger were seriously injured, the other two passengers were not injured. The airplane was in cruise flight when it began an uncommanded pitch up. The pilot was unable to keep the airplane from climbing and shut off the engine during his attempt to land. The airplane touched down on runway 21 and bounced several times before continuing off the departure end and crashing into trees. The airplane was equipped with a two-axis autopilot, which is being examined.