Deadhorse, AK, USA
N130AL
Bell 206L-3
The commercial helicopter pilot was flying three passengers to several remote sites in northern Alaska to collect snow samples. The snow was being collected from flat, featureless terrain. The pilot said that he was able to reach five of the six predetermined sites, but was unable to reach the sixth site due to low fog, reduced visibility, and flat light conditions. While attempting to return to the base camp, he encountered an area of low fog, which reduced his ability to discern a horizon. He said that the visibility diminished so that he was unable to discern any topographic features, and he elected to make a precautionary landing to wait for improved visibility. After about 3 minutes, he decided to return to the base camp. Just after takeoff, flat light conditions, and worsening fog conditions, reduced his ability to recognize any topographical features on the snow-covered tundra. He said that he initiated another landing, and lowered the collective when he believed the landing gear skids were on the ground. The skids were not on the ground, and the helicopter subsequently descended, and rolled to the right on ground contact. The helicopter continued to roll to the right, and the main rotor blades struck the ground. After striking the ground, the main rotor blades sheered off, and one main rotor blade struck the top left portion of the helicopter's cabin, passed through the left side of the cabin, and struck the passenger seated in the front left seat. The pilot reported that there were no preaccident mechanical anomalies with the helicopter.
HISTORY OF FLIGHT On April 30, 2004, about 1920 Alaska daylight time, a high skid-equipped Bell 206L-3 helicopter, N130AL, sustained substantial damage after colliding with snow-covered terrain, about 56 miles south-southwest of Deadhorse, Alaska. The helicopter was being operated as a visual flight rules (VFR) on-demand charter flight under Title 14, CFR Part 135, when the accident occurred. The helicopter was transporting three research scientists from the University of Alaska campus located in Fairbanks, Alaska. The research team was collecting snow samples at various remote sites from the snow-covered tundra of the North Slope. The contract holder, Veco Polar Resources, Inc., Denver, Colorado, was utilizing Air Logistics of Alaska, Inc, Fairbanks, to provide helicopter support services to the scientific research team. Of the four people aboard the helicopter, the certificated commercial pilot sustained minor injuries, the two surviving passengers sustained no injuries, and the third passenger sustained fatal injuries. Instrument meteorological conditions prevailed at the accident site. Visual meteorological conditions prevailed at the time of departure, and company flight following procedures were in effect. The flight originated about 1600, from the researcher's camp, known as Toolik base camp, located about 95 miles south of Deadhorse. During an interview with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on May 3, the pilot reported that on the day of the accident, fog delayed the flight's departure from the Toolik base camp until 1600. Before departing the base camp, the pilot contacted the Fairbanks Automated Flight Service Station (AFSS) and obtained a preflight weather briefing. Additionally, he reported that he was able to view satellite weather imagery using a laptop computer at the base camp prior to departure. The pilot said that after departing from the base camp, the flight proceeded northwest to a series of predetermined landing sites, marked using global positioning satellite (GPS) waypoints. At each of the sites, the researchers would exit the helicopter, collect snow samples, re-board, and then fly to the next site. The pilot said that he was able to reach five of the six sites, but was unable to reach the sixth site due to low fog, reduced visibility, and flat light conditions. He said while attempting to return to the base camp, flying in a southeasterly direction, he encountered an area of very low fog, which reduced his ability to discern a horizon. He said that the visibility deteriorated, and he was unable to discern any topographic features on the surface of the flat, featureless, snow-covered tundra. He elected to make a precautionary landing, and wait for visibility conditions to improve. After remaining on the ground for about 3 minutes, he decided to proceed towards the Toolik base camp. He said that just after takeoff, as the helicopter moved forward, flat light conditions, and worsening fog, contributed to his inability to recognize any topographical features. He reported that while he was attempting to land again, and erroneously believing that the helicopter's skids were already on the ground, he lowered the collective. The helicopter subsequently descended, the landing skids struck the snow-covered tundra, and the helicopter rolled to the right, with the main rotor blades striking the ground. As the main rotor blades struck the tundra, the helicopter continued to roll onto its right side, the main rotor mast sheered off, and one main rotor blade struck the top left portion of the helicopter's cabin. The main rotor blade subsequently sliced through the left side of the helicopter, and struck the passenger that was seated in the front left seat. The pilot stated that immediately after the accident he contacted the operator's Fairbanks based operations manager using a satellite phone, and informed him of the accident. The helicopter sustained substantial damage to the fuselage, tail boom, and main rotor drive train system. The pilot noted that there were no preaccident mechanical anomalies with the helicopter. A review of the Fairbanks AFSS telephone conversation tapes from April 30 indicated the pilot called at 0722 and requested a weather briefing for the current conditions at Deadhorse, the terminal forecast for Deadhorse, and the terminal forecast for Deadhorse area. The AFSS specialist provided the current weather conditions at Deadhorse, and the Deadhorse terminal forecast. According to AFSS telephone conversation transcripts, the accident pilot stated, in part: "Yes, I just want to get the uhh what Deadhorse has right now." The AFSS specialist on duty responded by saying, in part: "Okay, right now they're yucky." The AFSS specialist then provided the pilot with the current conditions at Deadhorse, which included, visibility of 1/4 of a mile in fog, and an indefinite ceiling of 100 feet. The AFSS specialist said: "So, it looks like they expect the fog to hang in there... Unfortunately, unless you want to crawl along on the ground." The accident pilot responded by saying: Yeah, that's what I've done for the last two days." The pilot then said: "OK, I may call back around ten then." At 1543, the pilot again contacted the Fairbanks AFSS and again asked the AFSS specialist on duty for the current weather conditions at Deadhorse. The AFSS specialist reported current Deadhorse weather conditions as: Wind 070 at 6 knots; five miles visibility in mist; ceiling 300 feet overcast; temperature 25 degrees F; dew point 23 degrees F; altimeter 30.31 inHg. A complete transcript of the telephone conversations between the accident pilot and the Fairbanks AFSS is included in the public docket for this accident. CREW INFORMATION The pilot held a commercial helicopter pilot certificate, and a helicopter instrument rating. In addition, he held a commercial airplane pilot certificate with airplane single-engine land, multiengine land, and an instrument airplane rating. The most recent first-class medical certificate was issued to the pilot on September 29, 2003. The pilot was hired by Air Logistics of Alaska on February 23, 2004. After completion of his initial ground and flight training, he satisfactorily completed an initial 14 CFR 135.293/.299 check ride on March 5, 2004, in an Air Logistics of Alaska Bell 206B helicopter. According to the NTSB Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) submitted by Air Logistics of Alaska, dated May 13, 2004, the pilot's total flight time consisted of 7,200.9 hours, of which 2,000 were accrued in the accident helicopter series. In the past preceding 90 and 30 days prior to the accident, the report lists a total of 69.9 and 23.9 hours, respectively. During a brief follow-up interview with the NTSB IIC on December 2, 2004, the accident pilot reported that his total flight time in Bell 206L-3 helicopters was 41.5 hours. He said that his time in a Bell 206L-3 helicopter was accumulated while employed by Air Logistics of Alaska, which included training and check ride flight time, as well as revenue producing flight hours. He added that the balance of his helicopter time reported by the operator was accumulated in a Bell 206B, and OH-58 helicopters. An OH-58 helicopter is a military variant of the Bell 206B helicopter. He said that a majority of his recent helicopter flight time was accumulated in US Military, UH-60 Blackhawk helicopters. At the time of the accident, the pilot was a full-time helicopter pilot for the United States Army. During his time in service with the United States Army, he was stationed in various theaters around the world, including Alaska. He accumulated about 6,144.0 flight hours in helicopters, and about 987.0 hours in airplanes. AIRCRAFT INFORMATION The helicopter was a Bell Helicopter Textron 206L-3, equipped with a Rolls Royce 250-C30P engine. The helicopter was maintained under the operator's Approved Aircraft Inspection Program (AAIP), which requires inspections to be performed approximately every 100 flight hours. The helicopter had accumulated 13,305.8 hours in service at the time of the accident. 1.6 hours had elapsed since the most recent Phase 1 inspection. METEOROLOGICAL INFORMATION The closest official weather observation station is located in Nuiqsut, Alaska, which is located about 47 nautical miles northwest of the accident site. On April 30, 2004, at 1853, an Aviation Routine Weather Report (METAR) was reporting, in part: Wind, calm; visibility, 8 statute miles; ceiling and clouds, 700 feet overcast; temperature, 25 degrees F; dew point, 21 degrees F; altimeter, 30.34 inHg. An AIRMET was issued for mountain obscuration in clouds and precipitation, with instrument meteorological conditions along the northern slopes of the Brooks Range. In a written statement to the NTSB dated May 1, 2004, the pilot included a description of the weather conditions at the time of the accident. He wrote, in part: "The weather had fog in the area with visibility of approximately 1/2 to 1-1/2 miles." WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board investigator-in-charge, along with three representatives from Air Logistics of Alaska, and a representative from the Federal Aviation Administration (FAA) Fairbanks Flight Standards District Office, attempted to reach the accident site by helicopter on May 1, 2004, but reduced visibility due to fog and flat light conditions prevented the helicopter from reaching the site until the following day. The topographical features surrounding the accident site consisted of smooth, featureless, and snow-covered tundra. There was a gradual upward slope in the direction of the accident helicopter's preaccident flight path. In addition, there was a set of helicopter skid tracks imprinted in the soft snow located about 162 feet northwest of the main wreckage site. The toes of the skid tracks were orientated on a 065 degrees magnetic heading. The skid marks matched those of where the accident pilot said he landed, waited for about 3 minutes, and departed from just before the accident. The helicopter fuselage and passenger cabin was lying on its right side, with the nose of the helicopter orientated on a 070 degree magnetic heading. The tail boom assembly was severed just aft of the tail boom attach points. The severed tail boom assembly came to rest in an inverted position. The forward cabin and passenger compartment was slightly bent, and buckled inward along the upper roof area. The left side of the front seat passenger's cockpit section was torn and crushed inwardly, which invaded the front seat passenger's area. The passenger side door, entire forward doorpost, and portions of the roof section, were torn from the helicopter. The aft landing gear cross tube saddle clamps that attach the helicopter's skid gear to the helicopter's belly, were crushed upward, into the surrounding honeycomb structure. The helicopter's aft cross tube appeared to be depressed, spreading the skids approximately 10 inches outward. The main rotor assembly was separated from the main rotor transmission. The main rotor mast, main rotor hub, main rotor blades, and swashplate assemblies were located on the left side, and just aft of the main wreckage site. The Bell 206L-3 helicopter has two metal-covered main rotor blades. Each main rotor blade is attached to the main rotor hub by means of a main rotor blade grip assembly. Each main rotor blade is color-coded for easy identification. The accident helicopter's red main rotor blade was discovered still attached to the main rotor hub assembly. The white main rotor blade was fractured about 18 inches from the main rotor grip assembly. Smaller fragments of the white main rotor blade were discovered within a close proximity of the accident helicopter's nose. A closer examination of the remaining portion of the white main rotor blade, revealed a 12-inch portion of structure that matched the passenger side doorpost structure. No evidence of preimpact mechanical anomalies were found. SEARCH & RESCUE Following the accident, a helicopter from the North Slope Borough Search and Rescue was dispatched from Barrow, Alaska, located northwest of the accident site. A second helicopter, a United States Army Medevac UH-60, was dispatched from Fairbanks, located about 250 miles south of the accident site. The search was joined by an Air Logistics of Alaska helicopter that is based at a remote oil pumping station, Pump Station 4. None of the search helicopters were able to reach the accident site due to low fog and reduced visibility. Members from the North Slope Borough Search and Rescue stationed in Nuiqsut, Alaska, about 47 miles northwest of the accident site, eventually reached the site on snow machines the following day, about 0740. The survivors were transported to Deadhorse via snow machines and a helicopter from the North Slope Borough Search and Rescue. ADDITIONAL INFORMATION According to Air Logistics of Alaska's safety manager, the following operational, training, and flight crew staffing changes were incorporated on June 7, 2004. These changes are, in part: (A) Helicopters will not be operated in Class G airspace at an altitude of 1,200 feet AGL or below, unless the in-flight visibility is at least 1/2 miles, and visual surface reference, which would allow for a safe landing, is maintained at all time during the flight. (B) Helicopters will not be operated in areas that are conducive to flat light, whiteout, brownout conditions or other areas of flat, featureless snow covered terrain, unless the in-flight visibility is at least 1 mile during daylight hours. In addition, a visual surface reference, which would allow for a safe landing, must be maintained at all times during the flight. (C) Pilots that do not have 100 hours of helicopter flight experience on the North Slope of Alaska, during the period from October 1 thru April 30 must comply with the following in-flight weather minimums to operate VFR aircraft, as pilot in command: (1) 3 miles visibility during daylight hours. AND (2) Maintain visual surface reference, which would allow for a safe landing, is maintained at all times during the flight. WRECKAGE RELEASE The National Transportation Safety Board released the wreckage to the general manager of Air Logistics of Alaska on May 2, 2004. No parts or components were retained by the Safety Board.
The pilot's continued VFR flight into instrument meteorological conditions (IMC), and his spatial disorientation and loss of control during a subsequent landing. Factors associated with the accident are flat light and whiteout conditions, fog, and snow-covered terrain.
Source: NTSB Aviation Accident Database
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