Page:CAB Accident Report, Alaska Airlines Flight 779.pdf/4

 The aircraft struck the embankment approximately 200 feet short of the threshold in a nearly level attitude, the nosewheel touching first about 18 feet below the crest, very nearly aligned with the centerline of the runway. The aircraft slid up the embankment during impact and when it reached the crest, broke in two (laterally) at the leading edge of the wings. The fuselage, wings, and tail section stopped and settled back on the slope. The powerplants, nose section, and the bulk of the cargo slid varying distances toward the runway and up on it for a distance of about 100 yards. Fire followed impact and the majority of the wreckage was consumed.

The cockpit area was damaged to such an extent that the positions of most of the control levers could not be determined. Three main fuel gauges showed 1,600 pounds of fuel remaining, and one showed 1,700 pounds. The alternate tank fuel gauges indicated empty. The copilot's altimeter was set at 29.86 and the pilot's altimeter was set at approximately 29.85. The wing flap indicator was damaged, but indicated a full-flap extension. The main inverter power switches were found in the "on" position and disassembly of both main inverters indicated that they had been rotating at the time of impact. The emergency inverter power switches were also found in the "on" position, but disassembly revealed that this inverter was not rotating at the time of impact.

The No. 1 VHF transmitter and receiver were set at 134.1 mcs., and the No. 2 VHF transmitter was set at 124.5 mcs., and the receiver was set at 125.4 mcs. The backup frequency monitored by GCA at Shemya during an approach is 121.5 mcs, (VHF Guard), and is the frequency which GCA expects a controlled aircraft to use if the pilot needs to transmit to GCA during the final approach.

The landing gear was fully extended and locked. The wing flaps were extended beyond the 30-degree position and the landing lights were extended. It could not be determined from physical examination of the switches whether any portion of the external lighting system was on or off. One witness, standing in front of the Northwest Airlines operations building, about midpoint of the runway, stated that he saw the navigation lights, landing lights, and rotating anti-collision light of the aircraft before it crashed.

All of the wreckage was found at the point of impact and forward of it. Examination of the aircraft and flightpath area revealed that the aircraft had not collided with any foreign objects prior to impact.

During examination of the powerplants, the fuel and oil strainers and the sump plugs were found to have been in apparently good condition and free from foreign matter. Firewall shutoff valves were in the open position, and the No. 4 fuel selector was on "main." All other selectors were damaged by impact or fire. Spark plugs were removed from all engines and were found to be free from any indications of fouling or peening. No fuel, oil, or ADI fluid samples were available; however, the aircraft had been serviced with 115/145 octane fuel at Anchorage. All propeller blades received extensive damage and were bent in various degrees toward the face. Several blades were broken off the propeller hubs, but examination of the blade fractures revealed no fatigue or breakage prior to impact. Examination of the propeller governors and propeller assemblies revealed engine r.p.m.'s to have been as follows: No. 1: 2,413 r.p.m., No. 2: 2,407 r.p.m., No. 3: 2,420 r.p.m., and No. 4: 2,416 r.p.m. The positions of the propeller dome