Page:CAB Aircraft Accident Report, Northwest Flight 293.pdf/2

 information which included area forecasts, regional forecasts, terminal forecasts, and weather reports pertinent to the proposed flight. Copies of these documents along with a NOTAM summary were attached to the flight plan provided to the captain.

The weather forecasts available to the captain and the dispatcher indicated the following: An occluded front gust east of Annette with occasional moderate turbulence expected near the front to an altitude of 22,000 feet and light to moderate icing expected west of the front (also scattered rain showers). Cloudiness of varied types and heights was depicted along the route with bases of the lowest indicated at 1,000-2,000 feet and tops going up to as high as 18,000-22,000 feet. Higher clouds were forecast over the northern end of the route.

The dispatcher stated that the 14,000-foot cruising altitude was selected because it "... allowed the flight to be between layers or on top most of the time. No other altitude offered any better forecast (weather) conditions. This altitude allows the aircraft to operate in low blower power configuration with lower cabin pressurization for passenger comfort. Most DC-7 crews prefer low blower operation as a more efficient operation."

The crew reported to SEA-TAC at approximately 1315 and the captain and the dispatcher discussed the forecast weather and the flight plan. After this briefing session the captain completed his flight plan and signed the flight release as did the dispatcher. The flight crew proceeded to McChord AFB and reported to Military Air Transport Service (MATS) operations. Here they received another weather briefing at 1534 from the USAF weather forecaster and were furnished with a Horizontal Weather Depiction Chart which included U.S. Weather Bureau, USAF, and Canadian Department of Transport weather data.

This forecast was essentially congruent with the earlier forecast. It indicated that the crew could expect light rime icing at 14,000 feet along the route from Port Hardy to Sandspit, B. C., and light to moderate rime icing from Sandspit to Domestic Yakutat, a point about 440 nautical miles northwest of Sandspit. The forecast also indicates light to moderate turbulence Just north of Domestic Sitka during frontal penetration.

After the weather briefing the captain completed a military aircraft clearance form, requesting an IFR flight clearance to Elmendorf AFB, Alaska, at l4,000 feet, via Airways Victor 287, Victor 4, Amber 1, control area 1310, and Victor 440 Airway to Anchorage, Alaska, thence direct to Elmendorf AFB. The estimated time for flight was 5:26 hours and the fuel on board was sufficient for 7:15 hours of flight.

The weight and balance form showed that the aircraft had a gross takeoff weight of 123,171 pounds and a takeoff center of gravity (c.g.) of 29.8 percent