LAX06LA092

the loss of power in both engines due to the ingestion of ice and snow. Also causal was the pilot's preflight and in-flight decisions to fly into areas of known and forecast moderate icing conditions in contravention to the prohibitions contained in the helicopter's Federal Aviation Administration approved Type Certificate Data sheet. A factor in the accident was the failure of the company maintenance organization to install the optional ice/snow deflector shields in front of the engine inlets that are designed to prevent the ingestion of ice and snow. An additional factor was the inaccurate and inappropriate weather briefing provided by the second AFSS specialist.

While en route on a positioning flight, the restricted category helicopter lost power in both engines and then landed hard and rolled over during an autorotative forced landing on a road. Both pilots said that as they neared the area of the accident site the flight had to maneuver around areas of bad weather. The helicopter was at 80 knots and 200 feet above ground level (agl) following a road while maneuvering around weather when a loud bang was heard and both engines suddenly lost power. The flying pilot entered an autorotation and managed to get the helicopter onto the road. The landing was hard and the main rotor blades flexed downward and damaged the empennage, then the helicopter rolled to the right. The pilot said that just prior to the loud noise and the dual engine failure, the engine instrument indications were normal and the fuel gauges were reading around 1,500 pounds in each tank. The fuel system was configured for normal operation; the number 1 engine feeding from the forward tank and the number 2 engine feeding from the aft tank, with boost pumps on and the crossfeed valve closed. The engine and airframe deice/anti-ice systems were on and functioning, and no annunciator lights were illuminated concerning any of the systems elements. The helicopter's Federal Aviation Administration approved and issued Type Certificate Data Sheet states that flight into known icing conditions is prohibited and notes that "the helicopters approved under this type certificate are done so under the concept of limited exposure associated with escape from inadvertent ice encounters." The anti-ice/deice systems on the helicopter consist of a combination of electrically and bleed air heated elements protecting the windshield, the oil tank mounting ring, engine air intake ducts, engine inlet guide vanes, starter cover, and the front frame of each engine. In addition to the anti-ice systems, an engine inlet ice deflector shield can be installed in front of the engine inlets to prevent any accumulation of ice and snow that forms around the upper deck and mast area ahead of the engines from entering the engine inlets. According to company Director of Maintenance and the subsequent examination of the wreckage, the optional engine inlet ice/snow deflector shields were not installed. The pilot received three preflight weather briefings from two separate Automated Flight Service Stations (AFSS), with the first two from the same station and the third from a different one. In the first briefing, the pilot was told that a routing from Oregon down to southern California could expect widespread IFR conditions due to mountain obscurement, clouds, precipitation, icing, and turbulence. An hour later the pilot called the same AFSS, but spoke to a different briefer, who told the pilot he had overheard the earlier briefing and then suggested the pilot consider a routing through northern Nevada to Utah, then south to Arizona. The specialist then stated that two stations east of the Cascade Mountain range had high scattered clouds with good visibility, and Winnemucca, Nevada, had current conditions of 8,500 broken. The pilot responded, "Oh, really." The specialist then said "it was...like clear below 12,000" all the way to Cedar City, Utah, and concluded with, "I think once you get by like Winnemucca or Elko (Nevada) things improve drastically." The pilot responded, "We may just try that." An hour and a half later the pilot called and reached a different AFSS facility and asked about the conditions on the northern Nevada routing. The specialist said that presently there were AIRMETS in effect over the route for moderate rime and mixed icing, moderate turbulence, mountain obscurement and general IFR conditions over the entire area. The specialist said that VFR flight was not recommended over that route and another two alternate routings the pilot inquired about, and he cautioned the pilot that icing conditions would be moderate rime and mixed icing in clouds and precipitation from the surface to 21,000 feet, especially in the Ely, Nevada, area. Analysis of the actual weather conditions disclosed that en route to the accident site, the helicopter probably encountered occasional snow showers with low ceilings and visibilities. The freezing level was at or near the surface and that in-flight icing was likely from the surface to 18,000 feet. The formation of airframe ice due to the freezing of melted snow was also possible. The airframe fuel and anti-icing systems were functionally tested and operated normally. The number 1 engine had inlet guide vane trailing edge and first stage compressor blade leading edge damage that was consistent with the ingestion of ice chunks. Detailed disassembly of the number 1 engine revealed no other damage, condition, or abnormality that would have precluded normal operation. The number 2 engine was not damaged and was installed in a test cell where it ran normally. The fuel system components from the number 1 engine where then installed on the number 2 and the test cell run repeated with identical results to the first test.

1.1 HISTORY OF FLIGHT On January 18, 2006, at 1330 Pacific standard time, a Croman Corporation SH-3H helicopter (modified version of a military Sikorsky SH-3H), N612CK, lost power in both engines and rolled over during a hard forced autorotative touchdown on a road 28 miles northwest of Ely, Nevada. Croman Corporation was operating the helicopter under the provisions of 14 CFR Part 91 of the Federal Aviation Regulations on a positioning flight. The helicopter sustained substantial damage. The two commercial pilots and two additional crew members were not injured. Visual meteorological conditions prevailed and a company flight plan was filed. The flight departed Winnemucca, Nevada, at 1130, en route to Page, Arizona. According to Federal Aviation Administration (FAA) records, an individual who identified himself as the pilot of N612CK called on the telephone and obtained three preflight weather briefings on January 18 at the times of 0628, 0730, and 0850. The first two calls were handled by the McMinnville, Oregon, Automated Flight Service Station (AFSS), and the last one by the Boise, Idaho, Automated Flight Service Station. Complete transcripts of these briefings were reviewed by National Transportation Safety Board investigators, and are contained in the Public Docket for this accident. In the 0628 call, the pilot requested a visual flight rules (VFR) weather briefing from the Medford, Oregon, area to Bakersfield, California, with an ultimate destination of Abilene, Texas. During this call, the pilot also requested weather information for the Truckee and Reno, Nevada, areas. According to the transcript, the AFSS specialist described the general conditions as being influenced by a low pressure system off the Oregon coast and a trough in western Oregon and Northern California with associated atmospheric instability. The specialist stated that instrument flight rules (IFR) conditions, due to reduced visibilities, clouds, rain, and fog, existed from southern Oregon down through the central portions of California to just above Bakersfield. Mountain obscurement was also forecast along with AIRMET's for moderate turbulence and moderate rime or mixed icing below 18,000 feet. Cloud tops were generally described as at 25,000 feet. Isolated thunderstorms scattered throughout the area were also predicted. The specialist concluded with a statement that the route down through California to the Bakersfield area "does not look like a good way even for a helicopter to go today, at least until after noon." The pilot then inquired about the Truckee/Reno area and the general conditions east of the Sierra Nevada Mountains. The specialist provided the information, which included multiple cloud layers, reduced visibilities below 3 miles, and snow showers. At 0730, the pilot telephoned again and requested another briefing for the same initial routing through Oregon and California to Bakersfield, with an ultimate destination of Albuquerque, New Mexico. The specialist said that he had a suggestion for the pilot to consider; if the pilot did not have to go through California for some reason that they should consider going through northern Nevada. The pilot replied that he thought northern Nevada's weather was "stinko" and that getting across the Sierra Nevada Mountains would be a big problem. The specialist then stated that two stations east of the Cascade Mountain range, Klamath Falls and Lakeview, Oregon, had high scattered clouds with good visibility, and Winnemucca had current conditions of 8,500 broken. The pilot responded, "Oh, really." The specialist then said that he had overheard the other specialist in the facility talking to the pilot earlier that morning and that he had looked at conditions east of Winnemucca and "it was...like clear below 12,000" all the way to Cedar City, Utah. The pilot then asked about the conditions south of Cedar City toward the Farmington/Albuquerque areas and the specialist told him the conditions were clear below 12,000 feet and concluded with, "I think once you get by like Winnemucca or Elko (Nevada) things improve drastically." The pilot responded, "We may just try that." In the 0850 telephone call (which was routed to another AFSS facility), the pilot asked for weather information for a flight eastbound from Klamath Falls, Oregon, to Cedar City, Utah, with stops in Winnemucca and Ely. The specialist told the pilot that presently there were AIRMETS in effect over the route for moderate icing, moderate turbulence, mountain obscurement and general IFR conditions over the entire area. The specialist said that VFR flight was not recommended over that route. The pilot then inquired about various alternative routings, including through southern Idaho. The specialist provided reports for the stations requested; the reports delineated varying conditions from visibilities less than a mile in snow to areas of multiple cloud layers with visibilities between 3 and 5 miles. The specialist said that icing conditions would be moderate rime and mixed icing in clouds and precipitation from the surface to 21,000 feet, especially in the Ely area. The pilot then concluded the telephone call. According to a verbal and written statements from the crew, the flight was to position the helicopter to Texas for a firefighting contract. The flight departed Winnemucca about 1130 with the intention of going all the way to Page, but with the understanding that they might have to stop somewhere en route due to weather conditions. Aboard was the second pilot, who was the flying pilot and acting as pilot-in-command for this leg, and two other company employees, a mechanic, and a third pilot. While en route the flight had to maneuver around areas of bad weather. Near the location of the accident there was a low ceiling and the helicopter was at 80 knots and 200 feet above ground level (agl) following a road while maneuvering around weather when a loud bang was heard and both engines suddenly lost power. The flying pilot entered an autorotation and managed to get the helicopter onto the road. The landing was hard and the main rotor blades flexed downward and damaged the empennage. A portion of the vertical stabilizer and the tail rotor gearbox were knocked off and the tail wheel separated. The helicopter then rolled to the right. The pilot said that just prior to the loud noise and the dual engine failure, the engine instrument indications were normal. He believes that the fuel gauges were reading around 1,500 pounds in each tank. The fuel system was configured for normal operation; the number 1 engine feeding from the forward tank and the number 2 engine feeding from the aft tank, with boost pumps on and the crossfeed valve closed. The engine and airframe deice/anti-ice systems were on and functioning, and no annunciator lights were illuminated concerning any of the systems elements 1.2 PERSONNEL INFORMATION According to information supplied by Croman Corporation, both pilots were qualified to act as pilot-in-command in the SH-3/S61 helicopters operated by the company. The information contained in this section of the report was obtained from the company, the pilots, and from the FAA Airman and Medical Records databases. The left seat is the normal command pilot station in the Sikorsky S-61/SH-3 helicopter. 1.2.1 First Pilot The pilot occupying the left seat held a commercial pilot certificate with a rotorcraft-helicopter rating that was last issued on June 21, 1993. The commercial certificate also contained type ratings for the MBB BV-107 and Sikorsky S-61 helicopters, both limited to VFR conditions only. The certificate was also endorsed for private privileges for single engine land airplanes. A second-class medical certificate was issued on July 21, 2005, without limitations. The pilot's total flight time was 20,000 hours, of which 19,800 were accumulated in helicopters. The pilot h