Accident at Yakutat, Alaska, 27 Nov 1947
On November 27, 1947, an aircraft operated by Columbia Air Cargo was involved in an aviation accident near Yakutat, Alaska. Investigators recorded the probable cause as: "failure to follow the approved instrument approach procedures while making an initial approach to Yakutat at an altitude insufficient to clear trees along the flight path. This summary draws on records from the U.S. Civil Aeronautics Board (CAB) accident report collection at the National Transportation Library; 1 related events involving the same aircraft type or operator are linked below.
Probable cause
"failure to follow the approved instrument approach procedures while making an initial approach to Yakutat at an altitude insufficient to clear trees along the flight path.
— NTSB Determination
Accident narrative
At approximately 0317 on November 27, 1947, a Columbia Air Cargo DC-3 crashed one mile east-northeast of the Yakutat Range Station in Yakutat, Alaska. The aircraft struck a tree during an unapproved straight-in approach, killing all 11 passengers and the crew of two, and totally destroying the airplane.
**The flight**
The aircraft departed Portland, Oregon, on November 25 for Anchorage, Alaska. The crew consisted of Pilot J. B. Haworth, who had 4,300 flight hours including 1,000 in DC-3 aircraft, and Copilot Toivo A. Keranen, who had 4,000 hours with 2,000 in DC-3s.
During the northbound landing at Anchorage, an engine was heard to overspeed. The crew executed a go-around, feathered the left propeller, and circled for 15 minutes before unfeathering it and landing normally. The left engine governor was removed, bench-checked, and found to be operating normally before being reinstalled. The left engine oil sump plug and strainer were also examined and found clear. The flight continued to Fairbanks without further trouble.
The return trip departed Fairbanks on November 26, planning stops at Anchorage and Yakutat. At Anchorage, the aircraft was serviced with 326 gallons of fuel. The right engine required 10 gallons of oil, and considerable oil was noted on the outside of its cowling. Copilot Keranen stated that the engine was due for overhaul upon reaching Portland and that it was all right for the remainder of the trip. No freight was aboard, and the aircraft was well within its certificated gross weight.
The flight left Anchorage at 0020 on November 27 with 11 revenue passengers and 600 gallons of fuel. At 0238, the crew reported over Yakataga at 6,000 feet, proceeding under instrument flight rules to Yakutat.
**The approach**
At 0306, the flight called Yakutat Radio, stating it was leaving 6,000 feet and making a "straight in" approach. The communicator transmitted the Yakutat weather: an indefinite ceiling with a 500-foot overcast, three miles visibility, light drizzle, and an altimeter setting of 30.17.
At approximately 0316, Yakutat Radio requested the flight report the height of the ceiling when it descended into the clear. The flight acknowledged with, "Okay Yakutat." Shortly after this final transmission, the airplane was heard flying at a low altitude over a residence 300 feet south of the Yakutat Radio station. Seconds later, the occupants heard an explosion.
**What the investigation found**
The left wing struck a 140-foot spruce tree one mile from the radio station on a bearing of 70 degrees. The top 10 feet of the tree was severed, and the left wing separated from the aircraft. The main wreckage plunged to the ground at a 38-degree angle, coming to rest 610 feet from the separated wing, and was largely destroyed by fire. The landing gear was extended, and broken turnbuckle bolts indicated the flaps may have been in the three-quarters down position.
The left propeller blades were bent straight back along the engine cowling, and two propeller segment gears were broken. The Board noted this indicated the propeller was stopped when it struck an object, most probably the tree. The Board stated there was a possibility the left engine failed prior to the crash, or as a result of striking trees, but insufficient evidence was found to make a positive determination. The right engine's propeller blades were found in low pitch with twisted tips, indicating it was rotating.
The Board found that a straight-in approach to Yakutat from the northwest had not been approved by the Administrator of Civil Aeronautics. Because no radio facility existed on the northwest course to provide a suitable fix, the approved standard radio range procedure required flights to cross the Yakutat range station at 1,500 feet, proceed outbound on the northwest course, execute a procedure turn, and return inbound before descending to the minimum approach altitude of 500 feet.
The Board noted that the pilot did not follow the approved procedure, instead accomplishing his entire descent while en route. The Board believed that the pilot, attempting to establish visual contact over the water during the last 100 miles of the flight, may have descended too low to clear the trees near Yakutat.
The Board also suggested the possibility that the altimeter may not have been adjusted to the correct barometric pressure, as the pilot never repeated or confirmed the setting given 11 minutes before the accident, though the destroyed instrument prevented verification. Even if the left engine had failed, the Board noted the lightly loaded airplane should have had little trouble maintaining altitude.
**Probable cause**
The Board determined that the probable cause of this accident was "failure to follow the approved instrument approach procedures while making an initial approach to Yakutat at an altitude insufficient to clear trees along the flight path."