ANC97FA024

History of flight

On January 29, 1997, about 2310 Alaska standard time, a De Havilland DHC-4A, N702SC, collided with terrain about 2.2 miles west of Sparrevohn Long Range Radar Station (LRRS), Sparrevohn, Alaska. The airplane was being operated as an instrument flight rules (IFR) cargo flight to Kenai, Alaska, under Title 14 CFR Part 135 when the accident occurred. The airplane, operated by South Central Air, Kenai, Alaska, was destroyed. The captain, a certificated commercial pilot, received serious injuries. The first officer, a certificated airline transport pilot, received fatal injuries. Visual meteorological conditions prevailed. An IFR flight plan was filed. The flight originated from St. Mary's, Alaska, about 2105 hours.

The captain reported the crew was involved in transporting mining equipment from Pilot Station, Alaska, to St. Mary's, and had made three trips between the two areas throughout the day. The final load of the day was a large mining air compressor that was secured in the cargo compartment. The flight landed at St. Mary's for fuel and service before departing on the accident flight to Kenai. The captain reported the fuel load was 2,800 pounds, and the cargo weighed 5,300 pounds.

After departure, the first officer was flying the airplane and the flight was progressing at 12,000 feet mean sea level (msl). The intended route of flight was from St. Mary's, via the Sparrevohn VOR, to Kenai. About 10 miles east of the Sparrevohn VOR, the right engine propeller began to overspeed. The captain feathered the right engine, and at 2252:25, the crew declared an emergency with the Anchorage Air Route Traffic Control Center (ARTCC), and reported the flight was diverting to Aniak, Alaska. The captain advised the first officer to perform a 180 turn back to the Sparrevohn VOR, and the flight was cleared by the ARTCC to descend to 6,000 feet. The captain considered making a landing at the Sparrevohn Airport, and requested the ARTCC obtain permission to land at Sparrevohn. The crew requested the weather conditions at Sparrevohn, and the ARTCC controller informed them the wind was calm, the visibility was 10 miles, and the sky condition was 8,000 feet with scattered clouds. At 2254:54, the crew canceled the request for landing at Sparrevohn, stating: "...center, 2SC, yea cancel that request, we'll just go back to Aniak, ah, there's not enough visibility down here to make a visual approach."

En route to Aniak, the captain advanced the power on the left engine, and he reported it began to produce banging and coughing noises. The airplane was unable to maintain altitude, and began descending about 300 feet per minute. At 2258:44, the ARTCC requested the crew change radio frequencies to receive the weather conditions reported in Aniak. The controller asked the crew to verify the flight was descending to 6,000 feet. The crew replied they were unable to maintain altitude. The controller verified the airplane was descending out of 7,700 feet.

At 2302:25, the crew informed the ARTCC of additional engine trouble, and requested the VOR/DME instrument approach to runway 34 at Sparrevohn. The captain took control of the airplane, and with the assistance of the first officer, began preparations for an emergency landing at Sparrevohn. At 2304:40, the crew requested the safest altitude for descent. The controller replied that the minimum altitude within 25 nautical miles is 5,800 feet. At 2305:42, the crew indicated they would fly the published approach and the controller requested the crew advise when they were over the VOR to proceed outbound on the 111 degree radial to intercept the 12 DME arc. At 2305:58, the crew indicated they were unable to maintain 5,800 feet. At 2306:19, the controller advised the crew to report over the VOR and at 2306:54 the controller stated: "...after you pass the VOR and you're established outbound on the 111 radial, the highest terrain is physically 3,436 feet and that is about half way out to the arc that will be on your left."

At 2307:36, the controller indicated that he observed the airplane at 5,400 feet and the crew concurred. At 2307:57, the crew stated: "...center, ah, we can pick up the runway identifier lights from this position, can we go straight in." The controller replied "... affirmative, if you have the runway, you're cleared for the visual approach, try to report your arrival this frequency." The crew replied in the affirmative, and the captain selected 15 degrees of flap and gear down, and began descending toward the airport while attempting to maintain visual contact with the runway.

At 2308:12, the controller inquired: "... 2SC roger, is that your intention and do you have the runway lights now." The crew replied, "...'unintelligible' have the lights and we're going for them 2SC." The controller inquired if the airplane was landing toward the north or toward the south. At 2309:09, the crew replied: "...only one approach to Sparrevohn sir 'unintelligible' north."

The captain reported the airplane encountered severe turbulence from the surrounding mountainous terrain, and he applied full power on the left engine to attempt a climb. During the turbulence encounter, the captain lost visual contact with the runway lights, and at 2309:30, the crew stated to the ARTCC controller: "...get them, can you call Sparrevohn sir and have them turn their lights on pronto." The captain recalled that he called for gear and flaps "up." He observed the left engine manifold gauge indicating 50 inches. The airplane then collided with snow covered, upsloping terrain in an area of high winds and blowing snow.

The accident occurred during the hours of darkness at latitude 61 degrees, 06.186 minutes north and longitude 155 degrees, 38.346 minutes west.

Crew information

The captain holds a commercial pilot certificate with airplane single-engine land, single-engine sea, multi-engine land, and instrument airplane ratings. In addition, the captain holds a mechanic certificate with airframe and powerplant ratings, and a type rating for the DHC-4 airplane. The most recent first-class medical certificate was issued to the pilot on December 13, 1996, and contained no limitations.

The captain is a check airman for all company pilots. He received an FAA proficiency check pilot authorization for DHC-4 airplanes, second-in-command only, on April 16, 1996. The captain received his initial and upgrade training for pilot-in-command in DHC-4 airplanes on September 29, 1995, which included 9 hours of flight training.

According to pilot records provided by the operator, the captain's total aeronautical experience consists of about 4,987 hours, of which about 220 hours were accrued in the accident airplane. In the preceding 90 and 30 days prior to the accident, the captain accrued a total of 120 and 41 hours respectively.

Examination of the captain's flight and duty records revealed he accrued .7 flight hours between 0700 and 1730 on January 27, 1997. On January 28, 1997, the captain's duty hours from 0700 and 1700, did not include any flight time. On the accident date, January 29, 1997, the captain's duty record indicated he reported to work at 0700. The operator reported that company personnel made that entry in error, without the captain's knowledge. The captain indicated he actually started work at 0900. The anticipated arrival time in Kenai for the accident flight was 2400.

The first officer held an airline transport pilot certificate with airplane single-engine land, multi-engine land, and instrument airplane ratings. He also held a flight instructor certificate with airplane single-engine and instrument airplane ratings. In addition, the first officer held a mechanic certificate with airframe and powerplant ratings. The most recent first-class medical certificate was issued to the first officer on August 26, 1996, and contained the limitation th