History of Flight
On November 29, 2013, at 1824 Alaska standard time, a Cessna 208B Grand Caravan, registration N12373, sustained substantial damage after impacting terrain approximately 1 mile southeast of St. Mary's Airport, St. Mary's, Alaska. The aircraft was operated by Hageland Aviation Services, Inc., doing business as Era Alaska, as a visual flight rules (VFR) scheduled commuter flight under 14 CFR Part 135. Of the ten people on board, the commercial pilot and three passengers sustained fatal injuries, and six passengers sustained serious injuries. Night, instrument meteorological conditions (IMC) prevailed at St. Mary's Airport at the time. The flight departed Bethel Airport at 1741 destined for Mountain Village, Alaska, but diverted to St. Mary's due to deteriorating weather conditions.
The day of the accident, the pilot arrived at the company office in St. Mary's about 0800. The accident flight was the pilot's fifth flight of the day. Hageland Aviation Services had recently incorporated a risk assessment program, but it had not been added to the company General Operations Manual. Before departure, the flight coordinator assigned a risk assessment level of 2 due to IMC, night conditions, and contaminated runways. A level 2 required a conversation between the flight coordinator and the pilot about hazards, but this discussion did not occur, and neither flight coordinator had received training on the risk assessment program.
The flight departed Bethel at 1741 with 10 souls on board and 4 hours of fuel. About 30 minutes into the flight, a passenger reported the aircraft entered thick fog and accumulated about 1/2 to 3/4 inch of ice on the lift strut. The pilot diverted to St. Mary's and at 1819:20 requested a special VFR clearance. The controller cleared the flight into the St. Mary's surface area and provided the altimeter setting of 30.35 inHg. This was the last communication. At 1822, sounds similar to a microphone keying were heard on the ARTCC frequency, but the pilot's radio was still selected to the ARTCC frequency, so the pilot-controlled lighting at St. Mary's did not activate. Witnesses reported the aircraft flew over the airport at about 300-400 ft heading southeast before its beacon disappeared.
About 1 hour after search initiation, the aircraft was located. Rescue personnel confirmed that the pilot and two passengers died at the scene; one passenger died after transport to the local clinic. The six surviving passengers were evacuated to Anchorage.
Personnel Information
The 68-year-old pilot held a commercial pilot certificate with single-engine land, sea, multiengine land, and instrument ratings, and had over 25,000 total flight hours with over 1,800 hours in Cessna 208 airplanes. His most recent FAA second-class medical certificate was issued August 21, 2013, with the limitation that he must wear corrective lenses. He completed initial Cessna 208B ground training on February 11, 2013, recurrent ground training on June 14, 2013, and flight training and a check ride on June 19, 2013.
Aircraft Information
The accident aircraft was a 1998 Cessna 208B Grand Caravan, registration N12373, with 12,653 total flight hours. The most recent inspection was completed on November 12, 2013. It was equipped with a Pratt & Whitney PT6A-114A turbine engine rated at 675 shaft horsepower, overhauled 4,655 hours before the accident. The aircraft was equipped for instrument flight and flight into icing conditions, and had a Honeywell KGP-560 Terrain Awareness and Warning System (TAWS).
Meteorological Information
At the time of the accident, an AIRMET forecast mountain obscuration due to clouds and precipitation. The nearest weather station, St. Mary's Airport, reported at 1816: wind 230 degrees true at 6 knots, visibility 3 statute miles, overcast ceiling at 300 ft agl, temperature 18°F, dew point -32°F, altimeter 30.35 inHg. The 1836 METAR reported wind 240 degrees true at 5 knots, visibility 2.5 statute miles, overcast at 300 ft agl.
Wreckage and Impact Information
The wreckage path extended about 200 ft along a heading of 122 degrees magnetic. The initial impact site included three ground disturbances: contact points of the main landing gear, followed by a crater where the nose and fuselage impacted the up-sloping terrain. The main wreckage was at an elevation of about 425 ft msl; the ridge top was about 530 ft msl. About 3/4 inch of ice was noted on nonprotected surfaces of the empennage. No preaccident anomalies were found with the airframe or engine.
Flight Recorders and ADS-B Data
The aircraft was not equipped with a cockpit voice recorder or flight data recorder. ADS-B data showed the aircraft passed 1 nm west of ONEPY intersection at 800 ft msl, then started a descent from 900 ft msl at about 3/4 nm from the runway 35 threshold. A right turn began at 1823:09, with an average turn rate of 7 degrees per second, ground speed 119 knots, descent rate 835 ft per minute. The last radar return at 1823:45 showed the aircraft at 450 ft msl (75 ft agl), heading toward rising terrain.
Additional Information
Examination of the GA-EGPWS revealed the terrain inhibit switch was in the "inhibit" mode at the time of the accident. The database installed was dated December 2006. The GA-EGPWS "Look-Ahead" alerting functions were de-sensitized near known runways, and no alerts would have been triggered given the aircraft's altitude and distance from the runway at impact.
Toxicological testing for the pilot was negative for carbon monoxide and ethanol but revealed 44.8 ug/ml of salicylate in urine, an over-the-counter analgesic.
The fuselage sustained extensive damage; the forward section was severely fragmented. The survivable cabin space was severely compromised. One of the four fatalities was an infant carried as a "lap child" in a forward-facing backpack carrier.
Organizational and Management Information
Hageland Aviation Services operated 56 airplanes with about 130 pilots at 12 bases. The company's risk assessment program assigned levels 1-4. At the time of the accident, both flight coordinators had completed initial flight coordinator training but not training on the risk assessment program. The pilot's flight and duty records showed duty days of 15-16 days per month, with the day of the accident being a 14-hour assigned duty day starting at 0800.