On December 18, 1998, about 1510 Alaska standard time, a Casa C-212 airplane, N502FS, operated by F.S. Air Service, Inc., of Anchorage, Alaska, sustained substantial damage during takeoff from the Nixon Fork Mine airstrip, located about 30 miles northeast of McGrath, Alaska. The airplane was being operated as an instrument flight rules (IFR) on-demand passenger flight under Title 14, CFR Part 135, when the accident occurred. The two certificated airline transport pilots, and the 18 passengers aboard were not injured. Visual meteorological conditions prevailed, and an IFR flight plan was filed for the return trip to the Anchorage International Airport. The outbound flight departed the Anchorage International Airport about 1345. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on December 22, the captain of the accident airplane reported that the airplane was being utilized for a crew change for the mining company that owns and maintains the airstrip. He stated that it had been previously agreed upon that the return trip to Anchorage was to be flown by the first officer. The captain said that the airplane was taxied to the south end of the airstrip in preparation for a north departure. He said that after he completed the before takeoff checklist, he applied the brakes, and held them while the first officer applied full takeoff power. He reported upon releasing the brakes, the aircraft accelerated to about 45 knots, and suddenly started pulling to the right. He added that both pilots pulled the power levers to the flight idle position as he took control of the airplane. He then applied full reverse thrust and heavy braking while trying to keep the nose straight, but the airplane kept pulling to the right. The captain added that in his opinion the left engine continued to produce thrust after he placed the engine control levers into the full reverse position. The airplane continued off the right side of the 4,400 feet long by 75 feet wide runway, down an embankment, and into an area of large boulders. The airplane sustained substantial damage to the fuselage and right wing. The captain stated that weather conditions at the time of the accident consisted of: Ceiling, 8000 feet thin overcast; visibility, 30 miles; wind 040 degrees at 10 knots, with gusts to 12 knots. The captain characterized the runway surface conditions at the time of the accident as "braking action fair, with a thin covering of snow mixed with gravel." At the request of the operator, both engines were removed from the airframe, and shipped to AlliedSignal Aerospace, Phoenix, Arizona. On April 8, 1999, in the presence of a National Transportation Safety Board investigator, the left engine and propeller were installed on an engine test cell. The NTSB investigator reported that the engine and propeller operated within acceptable parameters through out the testing process. A copy of the investigator's written report is included in this report. The Cockpit Voice Recorder was removed from the airplane and sent to the NTSB vehicle recorder laboratory in Washington, DC. A CVR listening group convened and was comprised of a chairman from the NTSB Office of Research and Engineering, an air safety investigator from the Anchorage FAA office, an accident investigator from AlliedSignal Aerospace, a technical representative from CASA Aircraft USA, Inc., and the director of operations of the airplane operator. At 1438:01, while approaching to land at the accident airstrip, about 32 minutes before the accident, the crew received a wind condition report from the Nixon Fork Mine operations office. The radio operator states " 'K, I have two zero knots out of the east on the runway right now, blowing snow across the runway." The first officer acknowledges receiving the wind condition report by saying "OK, two zero uh, knots out of the east, two Fox Sierra." The crew attempted a landing to the north, but discontinued the approach due to high winds and turbulence. A successful landing was then made to the south, and the airplane was taxied to parking. The Casa 212 airplane flight manual operating limitations section states "The critical crosswind component has not been determined. The maximum crosswind component demonstrated during takeoff and landings is 20 knots measured at a height of 50 feet above the runway, and is not considered to be a limiting factor." The CVR revealed that during the pre takeoff brief, about 29 minutes after landing, the crew discussed the wind conditions and planned for the use of differential power in order "to keep it on the runway." The following abbreviated sequence of events appears on the CVR: 1507:20 first officer: "takeoff brief?" 1507:21 captain: "yeah, do you wanna do it? I follow you up." 1507:23 first officer: "bas...basically ** hold it in there and we'll do uh, differential power." 1507:27 captain: "yeah." 1507:28 first officer: "...keep it on the runway." 1508:18 captain: "sixteen eight, see here's where it gets squirrelly worst you know. 1508:24 first officer: "yep." 1508:30 captain: "biggest trouble is gonna be here before we start rolling so you got control before you got sixty knots or you have control on the rudder you know." 1508:36 first officer: "OK." 1508:37 captain: "that's gonna be the toughest part." 1509:07 captain: "and if we do it, do it a little easier too. I kinda want to ...kinda zig zag little bit into the wind though, using a bit of the runway like this. 1509:16 first officer: " OK" 1509:21 captain: "so, when I steer you know, I will steer ya sorta diagonal toward the runway. That will help you uh.. 1509:29 first officer: "OK" 1509:30 captain: "OK" 1509:31 captain: "bring 'em up" 1509:31 first officer: "speeds comin high." 1509:32 captain: "yeah" 1509:36 sound similar to increase in propeller RPM. 1509:39 first officer: "hey, power system's looking normal 1509:40 captain: "OK." 1509:41 first officer: "OK. I wanna go with the left one a little more? 1509:43 captain: "I, I keep you goin' here now so." 1509:47 captain: "ah ah, not too much." 1509:48 captain: "too much, too much." 1509:49 first officer: "come come, come back." 1509:50 captain: "yeah." 1509:51 first officer "there we go." 1509:52 captain: "OK let me do it." 1509:53 first officer: "OK. You got that." 1509:54 captain: "I take it." 1509:54 first officer: "oop" 1509:57 first officer "come on back" 1509:59 captain: "as ____." (expletive) 1510:00 sound of impact, and end of recording. A complete transcript of the CVR is included in this report. The Safety Board released the CVR to the owner on February 22, 1999. No parts or components of the airplane were retained by the Safety Board.