Page:CAB Accident Report, Alaska Airlines Flight 779.pdf/5

 pistons were as follows: No. 1: 32°; No. 2: 30°; No. 3: 33°; and No. 4: 31°. The specified low-pitch stop was 30°. The shim plate markings were reasonably similar to the dome piston settings.

There was no evidence to indicate that the cargo had shifted prior to impact. The weight distribution of the cargo was such that the center of gravity remained within safe limits. The maximum allowable takeoff weight was 107,000 pounds and the adjusted takeoff weight at Anchorage was 107,006 pounds. The maximal allowable landing weight was 92,360 pounds. At 0135, when the flight was approximately 50 miles east of Shemya, and entry was made on the Flight Engineer's Fuel Management log showing a gross weight of 92,346 pounds. The log also showed that at 0135, the four main fuel tanks had 1,800, 1950, 1950, and 1,800 pounds of fuel, respectively, remaining. The four alternate tanks had been empty, according to the log, approximately one hour and 30 minutes prior to the 0135 log entry.

According to the Alaska Airlines flight manual, the r.p.m. setting for the engines was to have been 2,400 for final approach (for 4-engine operation) and 2,600 r.p.m. (for 3-engine operation). The manual also stated that 120-130 knots should be maintained while descending on the glide slope to the airport.

On the day following the accident, it was discovered for the first time that an electric power cable lying along the side of the runway had been cut two days prior to the accident to allow construction vehicles to pass over the area. This cable was the powerline leading to the six pairs of red approach lights off the end of runway 10, as well as to two of the four green threshold lights, and to the first four pairs of runway lights. This condition was not reported by previous landing aircraft, nor was a Notice to Airmen concerning this irregularity issued by Northwest Airlines, the operator of the airport. By splicing the cut cable and replacing a transformer in the circuit, all the formerly inoperative lighting was restored. The strobeacon was not included in the cut circuit, although it was disconnected by the impact of the wreckage. The main rheostat, which controls all lighting intensity (except the strobe light), was set on maximum brightness during the flight's approach.

The GCA unit used at Shemya was an AN/FPN-33 Quad Radar manufactured by Gilfillan Brothers Inc., of Los Angeles, California, and was operated under contract to Northwest Airlines, Inc., by the Micro-Craft Corporation. The GCA equipment was given a complete functional check by the GCA maintenance man and the operator prior to its use on July 20, 1961, and was operating, according to them, within tolerances. During the 12-hour period preceding this flight's approach, six other aircraft had made successful GCA approaches to Shemya using the same equipment manned by the same controller.

On May 3, 1961, and July 12, 13, 14, and 15, 1961, the GCA facility was flight-checked by the FAA and found to have been within tolerance. However, it was pointed out by the flight check crew in their report at the time of the latter flight check that, "It would appear from personal examination that the present radar antenna system now in use . . . has deteriorated and worn beyond its normal life and tolerances, and is anticipated that it will be difficult to maintain within acceptable tolerances in the very near future."

On July 22 and 24, 1961, the facility was again flight-checked by the FAA and found within tolerances. The check pilot gave the controller a proficiency rating