NTSB Factual Report

HISTORY OF FLIGHT

On August 31, 2010, at 0355 central daylight time, a Bell 206L-1, N62AE, owned by Air Evac EMS, Inc, (Air Evac) and operated as Air Evac 30, was substantially damaged when it impacted terrain following an in-flight break-up near Walnut Grove, Arkansas. Dark night instrument meteorological conditions prevailed at the time of the accident. The emergency medical services (EMS) positioning flight was being operated under the provisions of 14 Code of Federal Regulations (CFR) Part 91 on a company flight plan. The pilot, flight nurse, and flight paramedic were all fatally injured. The flight departed Vilonia (AE30), Arkansas, at 0335 and was en route to Crabtree, Arkansas, to pick-up a patient.

According to recorded communications, the request for the accident flight came from the Van Buren County 911 dispatch at 0316:45. The county dispatcher contacted the Air Evac Communications Center (located in West Plains, Missouri), and requested that a flight be placed on standby to transport a patient from Crabtree, Arkansas. The dispatcher commented that she was not sure the flight could go, as they had "some crappy weather" in Van Buren County. The communications center operator stated that the crew would check weather and let them know if the flight could be accepted. The Air Evac communications center contacted the flight crew of Air Evac 30 at 0319 and at 0322, the flight crew confirmed that the weather was "good" for the flight. Air Evac 30 was dispatched at 0322:36.

Air Evac 30 contacted the Air Evac communications center on the LONOKE communications tower, operated by Air Evac, at 0339:35 and provided souls and fuel on board, estimated time en route of 27 minutes, a planned altitude of 1,200 feet above ground level (agl), and a risk assessment score of 15.

Radar data, provided by the Federal Aviation Administration (FAA), identified and depicted the accident flight from the time of departure from AE30 to the time of the accident. The helicopter climbed to an altitude ranging from 2,000 to 2,600 feet mean sea level (msl). The last radar information was recorded at 0355:45 at an altitude of 2,700 feet msl.

The helicopter was equipped with a Garmin 396 Global Positioning System (GPS). The tracklog recovered from the unit began at GPS coordinates of 35 degrees 5 minutes 0.02 seconds north and 092 degrees 12 minutes 0.9 seconds west at 0335:35. The final GPS location was recorded at 0355:52 at GPS coordinates of 35 degrees 33 minutes 41.98 seconds north and 092 degrees 33 minutes 9.7 seconds west at an altitude of 1,760 feet. The last calculated velocity and direction of travel was 70 knots groundspeed with a course of 001 degrees true. The last minute of data depicted a turn to the left, a turn to the right, a reversal to the left, a reversal back to the right, and then a final reversal to the left.

In addition to the FAA radar data and the Garmin GPS data, Air Evac 30 was being tracked by the company's operational control center utilizing a flight-tracking program and equipment entitled Skytrac. This program logged information such as location, altitude, flight path, and velocity, and was updated every 60 seconds. According to the Skytrac log, Air Evac 30 was first identified at 0337 south, southeast of the Vilonia base. The flight track was the same as the tracks depicted by the radar and GPS data. The last position was recorded at 0354, 4.4 miles south southeast of the Ozark Health Medical Center at an altitude of 1,800 feet and a ground speed of 119 knots.

Several witnesses in the area reported hearing the sounds of the rotor blades as normal and then heard the sound of the rotor blades slow in speed. One witnesses reported seeing the helicopter circle above his home. Another witness reported hearing an "explosion" and shortly thereafter the sound of crushing or crashing metal and "tin." Another witness reported hearing an increase in the engine sound before hearing the helicopter impact the ground.

The wreckage was located in forested and rolling terrain, at GPS coordinates of 35 degrees 33.7 minutes north and 092 degrees 33.25 minutes west.

PERSONNEL INFORMATION

The pilot, age 35, held a commercial pilot certificate with airplane single engine land, rotorcraft helicopter, and instrument helicopter ratings. He also held an airline transport pilot certificate with an airplane multiengine land rating. He was issued a second-class airman medical certificate on August 25, 2010, with no limitations.

Air Evac hired the pilot, in September of 2007. According to Air Evac's records, the pilot had logged no less than 3,312 hours flight time in rotorcraft; 489 of which was in the make and model of the accident helicopter, 622 hours at night, and 311 hours under actual and simulated instrument conditions. He was a former military pilot and had logged more than 200 hours of night vision goggles (NVG) flight experience. The pilot had accumulated 35 hours in the past 90 days and 12 hours at night. The company flight records did not reflect the pilot's instrument experience within the previous 90 days. The records reflected that the pilot had accepted eleven night flights within the previous three months, five of which were aided by the use of NVG. At the time of the accident, he was the base pilot supervisor in Vilonia, Arkansas.

The pilot's airman competency/proficiency check for CFR 135.293 (Initial and recurrent pilot testing), and CFR 135.299 (Pilot in command: Line checks: Routes and Airports) was completed with a satisfactory rating in all tested areas on September 1, 2009. A company check-airman conducted the flight check in a Bell 206L helicopter in daylight conditions. The pilot had been trained for the use of night vision imaging systems (NVIS) including the NVGs. The pilot received his NVG ground training on December 7, 2009, and his NVG flight proficiency checkride on December 11, 2009. This check was completed in a Bell 206L helicopter. During this training, he received simulation in inadvertent flight into instrument meteorological conditions (IIMC).

Air Evac's records showed that the pilot's work schedule was 7 days on followed by 7 days off. He had been on the day shift (0700 to 1900) from August 12, 2010, through August 18, 2010; had seven days off, and then started duty for the night shift (1900 to 0700) on August 26, 2010. During the recent night shift rotation, the pilot had logged 2 hours and 30 minutes of flight time on the shift three days prior to the accident. This time included 0.2 hours during the day, 0.6 hours at night, and 1.7 hours while aided using NVGs.

According to Air Evac's director of safety, there were no safety issues or occurrences that involved the accident pilot.

AIRCRAFT INFORMATION

The accident helicopter, a Bell 206L-1 (serial number 45169), was manufactured in 1978. It was registered with the FAA on a standard airworthiness certificate for normal operations. A Rolls-Royce 250-C30P turboshaft engine rated at 650 shaft horsepower powered the helicopter. The helicopter was equipped with a two-blade main rotor system.

The helicopter was registered to and operated by Air Evac EMS, Inc., and was maintained under an approved aircraft inspection program. A review of the maintenance records indicated that a 150-hour inspection of the engine had been completed on August 29, 2010, at an airframe total time of 24,686.9 hours. An event two inspection was conducted on August 15, 2010, at an airframe total time of 24,664.2. The helicopter had flown 2.6 hours between the last inspection and the accident, and had a total airframe time of 24,689.5 hours.

The helicopter was equipped for flight into instrument meteorological conditions but was not Instrument Flight Rules (IFR) certified. The helicopter was equipped with a radar altimeter and a NVIS had been installed in July of 2009. The helicopter was not equipped with Helicopter Terrain Awareness Warning System (HTAWS), nor was it required to be. The helicopter was equipped with the Garmin 396, which provided terrain awareness warnings through a visual and aural warning.

METEOROLOGICAL CONDITIONS

Infrared satellite imagery of Arkansas displayed clouds directly over the accident site. The images depicted a layer of low clouds and stratus prevalent from southern Missouri southward into Arkansas, Louisiana, and Mississippi. The low cloud cover and stratus increased in areal coverage over time and covered the majority of Arkansas, Louisiana, western Mississippi, and southern Missouri by 0415. Doppler weather radar did not depict precipitation returns in the area at the time of the accident.

The upper air sounding parameters indicated a moist stable environment from the surface to approximately 2,500 feet msl, which supported low clouds and stratus below 2,500 feet. The inversion at 2,000 feet also acted to increase the areal coverage of the low clouds and stratus across Arkansas. Above 2,500 feet, the atmosphere was conditionally unstable, which supported stratus and stratocumulus cloud development to 7,000 feet.

The National Weather Service (NWS) had issued AIRMET (Airman's Meteorological Information) Sierra for instrument meteorological conditions due to low ceilings and poor visibility. The Area Forecast advised of marginal visual meteorological conditions in the state of Arkansas.

The closest official weather observation station was Clinton Municipal Airport (KCCA), Clinton, Arkansas, located six nautical miles (nm) northeast of the accident site. The elevation of the weather observation station was 514 feet msl. The routine aviation weather report (METAR) for KCCA, issued at 0355, reported, winds calm, visibility 10 miles, sky condition few clouds at 1,600 feet, broken clouds at 4,900 feet, overcast at 6,000 feet, temperature 25 degrees Celsius (C), dew point 23 degrees C, altimeter 30.09 inches.

METARs reported visibility of 5 miles in mist 1.5 hours prior to the accident. A visibility as low as 4 miles in mist was reported up to 3 hours prior to the accident.

According to the United States Naval Observatory, Astronomical Applications Department Sun and Moon Data, the sunset was recorded at 1938 and the end of civil twilight was 2004 (both on August 30). The Moon rose at 2230 (August 30), and at the time of the accident was 72 degrees above the horizon at an azimuth of 139 degrees. The phase of the Moon was waning gibbous with 60 percent of the Moon's visible disk illuminated above the clouds.

Several witnesses in the immediate vicinity of the accident location reported the weather as hazy or foggy, with overcast skies. One witness stated that it was very dark and no moon could be seen.

There was no record that the pilot obtained a weather briefing from the FAA Flight Service Station or Direct User Access Terminal System (DUATS). According to Air Evac, each base was equipped with a computer terminal, allowing the pilots to frequently check the weather. Air Evac encouraged their pilots to use Aviation Digital Data Services (ADDS), Weather Tap, and Flight Service Stations. In addition, each helicopter was equipped with XM (satellite radio) weather information. It could not be determined which resources were used by the pilot prior to the flight. The weather was not discussed with the dispatcher prior to or during the flight.

COMMUNICATIONS

Recordings of communications between Van Buren County and Air Evac 30 were provided to the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) for review. The final recording, with a time stamp of 0356:32 captured one clear transmission from Air Evac. A male voice was heard to say, "Base, Air Evac three zero..." In addition, a short tone, which increased in pitch, was heard in the background. The source of the tone was not identified. The remainder of that recording contained communications between the ground unit transporting the patient and the base operator.

FLIGHT RECORDERS

The accident helicopter's Garmin GPSMAP 396 (serial number 28218729) unit was sent to the NTSB Vehicle Recorders Lab in Washington, D.C. for download. The unit sustained major damage and could not be repaired. The FLASH memory device was removed from the main printed circuit board for extraction of flight data associated with this accident. Downloaded tracklog data included date, time, latitude, longitude, and the GPS altitude. One tracklog was recovered from the unit corresponding to the accident flight.

WRECKAGE AND IMPACT INFORMATION

The accident site was located in forested, rolling terrain at an elevation of 585 feet msl. The main wreckage consisted of the instrument panel, landing skids, engine, transmission, and cabin area. The wreckage was damaged by impact forces and was charred, melted, and partially consumed by fire. A circular burn area extended north from the main wreckage. The main rotor mast was imbedded approximately three feet diagonally in the ground.

Fuselage doors came to rest west of the main wreckage. One door remained in a tree overhead and to the west of the main wreckage.

The debris field initiated at a point north of the main wreckage. The helicopter chin bubble was located 0.5 miles north of the main wreckage at an elevation of 930 feet msl. Paper manual pages from a medical manual and fragmented Plexiglas were contained within the debris field, which proceeded on a southeasterly vector, for one-half of a mile, to the main rotor assembly.

The main rotor assembly, which consisted of the main rotor hub and the main rotor blades, came to rest 715 feet northwest of the main wreckage at an elevation of 611 feet msl.

The white rotor blade remained attached to the main rotor hub and was found inverted to its normal position in flight. A portion of the main rotor tie down strap was wrapped around the white blade. A puncture hole, one inch in diameter, was noted two inches inboard from the trailing edge of the blade, 67 inches outboard from the center of the mast. A second puncture hole seven inches by three inches triangular was noted along the trailing edge strip 94 inches outboard of the center of the mast. This puncture terminated five inches from the leading edge. A tear was noted that extended from 99 inches to 115 inches from the center of the mast. This tear originated from the second puncture, extended along the spar to 115 inches, and angled up towards the trailing edge terminating at 120 inches. The white blade exhibited light scraping marks along the back of the blade at 102 inches through 108 inches and again from 130 inches to 145 inches. Two additional trailing edge tears were noted at 135 inches and 142 inches. Thirty five inches of the trailing edge strip separated partially from the white blade and was bent and twisted outboard, ending its separating at the outboard trim tab. The tip of the white blade separated in an angular direction from outboard tip to inboard.

The tie down strap bag was in a tree directly above the main rotor assembly.

The red rotor blade remained attached to the main rotor hub and was upright as it lay. A puncture hole was noted at 3 inches from the center of the mast. A circular scoring or scratch that started at 84 inches and extended to 127 inches was noted on the blade face. This scoring started at the blade tear and extended outboard. Several puncture holes were noted in the blade face with Plexiglas imbedded within.

The red pitch change link remained attached to the main rotor hub assembly.

The tail boom, which consisted of the horizontal and vertical stabilizers, tail rotor driveshaft, tail rotor gearbox, and tail rotor assembly, came to rest 190 feet southwest of the main wreckage at an elevation of 578 feet msl. The piece measured 14 feet 8 inches in length and came to rest upright. Impact damage was noted to the extreme upper and extreme lower vertical stabilizer tips. Dirt was imbedded in each damage point. An adjacent rock, three feet south of the tail boom exhibited paint transfer consistent with the stabilizer and had a shape consistent with the damage to the stabilizer.

Both tail rotor blades remained attached. One blade was bent 35 to 40 degrees near the blade root. The other blade exhibited a crease near the blade root.

The tail rotor driveshaft was rem

NTSB Probable Cause

The pilot’s loss of aircraft control, due to spatial disorientation, resulting in the in-flight separation of the main rotor and tail boom.