Aviation Accident Summaries

Aviation Accident Summary SEA04GA192

Essex, MT, USA

Aircraft #1

N206SM

Cessna U206G

Analysis

The purpose of the public use flight was to transport four United States Forest Service (USFS) employees to a remote back-country airstrip. The flight's departure was delayed 2 hours due to heavy rain showers and a thunderstorm. The planned flight route was to follow a highway through a river valley with high terrain (peaks above 8,000 feet) on both sides until reaching a point where the highway diverged from the river. At that point, the flight was to leave the highway and follow the river. Analysis of available weather data indicated that as the airplane proceeded along the river valley, ridge tops on both sides of the valley became obscured. Bases of the overcast were probably about 7,000 feet msl. Ragged clouds and mist were probably present beneath the overcast due to recent rain showers in the area. Slant visibility was likely diminished. Local pilots reported that in these type weather conditions the numerous drainages that feed into the river valley can be similar in appearance. The pilot made a position call about 15 minutes after takeoff stating that he was over a small town located close to the point where the flight was to leave the highway. This was the last radio communication received from the airplane. Analysis of radar data available for the first 8 minutes of the flight indicated the airplane was not at the position reported by the pilot, but was actually well short of this position. About 15 minutes later, witnesses heard and saw the airplane flying up a drainage located short of the reported position. This drainage ended in a box canyon. Inspection of the accident site indicated that the airplane was in a left climbing turn when it impacted steep terrain near the head of the drainage at an elevation of about 6,600 feet. The airplane nosed over, came to rest inverted, and a fire erupted. Three of the occupants exited the burning wreckage. All communications equipment, survival equipment and foul-weather gear aboard the airplane were destroyed in the fire. One of the three initial survivors died from his injuries the following morning. At that time, the remaining two survivors decided to depart the site for lower elevation due to extreme cold and precipitation. Searchers found the wreckage later that afternoon. The two survivors walked out to the highway 2 days after the accident. No abnormalities were noted during examination of the airplane that would have prevented normal operation. When the pilot took a check ride that allowed him to act as pilot in command of public use flights carrying passengers into the back-country, he reported to the check pilot that he had 100 hours flight time in "typical terrain (over mountains)." USFS standards required 200 hours flight time in typical terrain. However, the standards did not define typical terrain. Examination of the pilot's logbook revealed that it did not include a specific record of back country or mountain flying experience. Review of the past 2 years of logbook entries revealed a total of only 15 entries (14 hours flight time) that included a takeoff or landing at a back-country airport.

Factual Information

HISTORY OF FLIGHT On September 20, 2004, approximately 1530 mountain daylight time, a Cessna U206G, N206SM, impacted mountainous terrain while maneuvering about 6 nautical miles northwest of Essex, Montana. The airplane was being operated under contract to the United States Department of Agriculture, Forest Service (USFS) by Edwards Jet Center of Kalispell, Montana, as a public use flight. The purpose of the flight was to transport a forest inventory team from Kalispell to the Schafer USFS Airport, Schafer, Montana. Four USFS employees and an Edwards pilot were on board. The pilot and two USFS employees were killed, and the other two USFS employees sustained serious injuries. Visual meteorological conditions prevailed for the airplane's departure at 1500 from Glacier Park International Airport in Kalispell. An FAA flight plan was not filed; however, the airplane was receiving flight following services from the USFS. According to USFS personnel, the flight was originally scheduled to depart at 1300. The scheduled departure was delayed from 1300 to 1500 due to weather conditions. The planned route of flight was to follow Highway 2 from Glacier Airport to a point about 3 miles south of the town of Essex, where the highway and the Middle Fork of the Flathead River separate. At this point, the flight was to leave the highway and follow the Middle Fork drainage to Schafer. According to personnel at the Glacier Airport Tower, their last contact with the airplane was at 1508, when the pilot reported that he was through "the canyon" (Badrock Canyon approximately 8 miles northeast of Glacier Airport) and switching to "backcountry frequency" (USFS dispatch). Examination of radar data confirmed that at 1508, the airplane was exiting Badrock Canyon heading northeast. Radar contact with the airplane was lost at this time due to mountainous terrain. From Badrock Canyon, the airplane's planned route proceeded along Highway 2, which follows a large bend in the Middle Fork of the Flathead, heading first northeast, then east, and finally southeast towards Essex. At 1515, the airplane checked in with USFS dispatch, and the pilot reported his position as "Essex, inbound for Schafer." This was the last radio communication received from the airplane. The distance from Badrock Canyon to Essex via Highway 2 is approximately 33 miles. In order for the airplane to reach Essex from Badrock Canyon in 7 minutes, it would have had to travel at a groundspeed of approximately 280 mph. According to the Cessna Model U206G Information Manual, the airplane's maximum airspeed for all operations (red line) was 211 mph (183 knots) and its maximum structural cruising airspeed (upper limit of green arc) was 172 mph (149 knots). At maximum structural cruising airspeed, the airplane would have traveled about 20 miles in 7 minutes, which would have placed it in the vicinity of Nyack at 1515. Nyack is a small town located about 13 miles north of Essex on Highway 2. One of the survivors reported that she was seated in the middle right seat and was wearing a headset that allowed her to hear the pilot and the right front seat passenger talking during the flight. She recalled the pilot making a radio call saying they were over Essex. About 5 minutes later, she noticed they were flying into a valley. At that time, the front passenger looked back and then asked the pilot, "Is that the Middle Fork?" The pilot replied, "Yes, that's the Middle Fork." The survivor recalled looking out the right side window and seeing snow on the peaks and then noticed they were "really close to the ground." She looked back forward and the airplane impacted. The other survivor reported that he was seated in the middle left seat and was not wearing a headset. He recalled they made a right turn out of the main river valley and started flying up "a pretty tight canyon." As they continued up the canyon, the "scenery got more and more dramatic" and "the canyon started to close in a little bit." He felt their elevation was not high enough and realized they were going to crash. Within seconds, the airplane impacted. About 1530, a USFS employee, located on Road 1637, observed an airplane flying up the Tunnel Creek drainage. Tunnel Creek originates from a small lake near the crest of the Flathead Range at an elevation of about 6,600 feet and flows east-northeast until it crosses Highway 2 and runs into the Middle Fork of the Flathead River about 7 miles south of Nyack and 6 miles north of Essex. The employee had been monitoring the radio in his vehicle and had heard the pilot of the airplane report over Essex. He estimated that it was approximately 15 minutes later that he made the sighting; at the time, he did not know if it was the accident airplane that he saw. The employee reported that the airplane was heading west to southwest, paralleling the ridge that forms the northern boundary of the Tunnel Creek drainage. The employee further reported that the airplane appeared to be in level flight, at an elevation near the top of the ridge, below a cloud layer that was obscuring the top of the ridge. About 1610, after hearing that a search for a missing airplane was in progress, the employee reported the sighting to USFS dispatch. Two bow hunters who were hunting in the vicinity of Road 1637 about 1530 reported hearing the sound of an airplane engine "laboring, then two pops, then nothing." This report was not made until about 1315 on September 21, when the two hunters were returning to their vehicle and encountered USFS personnel involved in the ground search for the airplane. When the airplane did not check in with USFS dispatch as expected at 1530, a search was initiated. An airplane from Edwards Jet Center and a helicopter under contract to the USFS searched by air until about 1725, when they were called back for the evening due to impending darkness and obscured mountain peaks. Based on the sighting of an airplane flying up the Tunnel Creek drainage by a USFS employee, the helicopter conducted a search of that drainage about 1700. According to the helicopter pilot, who viewed the accident site after it was discovered the following day, the cloud bases in the drainage prevented him from reaching the elevation of the accident site during his search on the day of the accident. At 1827, the airplane was officially declared missing having passed the time limit for fuel on board (3.5 hours). Montana Aeronautics Division assumed command of the aerial search, and the Flathead County Sheriff's Office assumed ground search responsibilities. About 0730 on September 21, a group of airplanes launched from Glacier Airport to search assigned grids. According to the aerial search coordinator, the airplane assigned to the grid where the accident site was eventually located flew along Highway 2 from Nyack towards Essex, but was unable to penetrate very far up the drainages from the Middle Fork of the Flathead due to low cloud bases. About 0945, while en route to his assigned grid, the pilot of the helicopter that had searched the Tunnel Creek drainage on the afternoon of the 20th, flew through the head of the Tunnel Creek drainage, but did not spot the wreckage. The pilot later reported that he was at a higher elevation in the drainage than the accident site when he made this over flight. The wreckage of the airplane was spotted by ground searchers about 1345 on September 21, 2004. Search and rescue personnel reached the accident site via helicopter about 1510. The Deputy Coroner for Flathead County inspected the scene and announced that all five occupants were fatally injured. The ground search was suspended. Approximately 1430 on September 22, 2004, the two survivors walked out of the Tunnel Creek drainage. PERSONNEL INFORMATION The pilot held an airline transport pilot certificate with a multi-engine land airplane rating and commercial privileges in single engine land airplanes. Additionally, the pilot held a flight instructor certificate with single and multi-engine airplane and instrument airplane ratings. His most recent second class medical certificate was issued on October 22, 2003, with the limitation, must wear corrective lenses. The pilot was hired by Edwards Jet Center in May 2004. Review of the pilot's logbook indicated he received 4.3 hours of 14 CFR Part 135 flight training during two separate flights in the accident airplane in April 2004. According to the instructor who provided the training, in order for a pilot to be eligible to fly for the USFS and "use the mountainous airports, they have to have a minimum of one takeoff and landing at [each] airport they are going to use." For that reason, during the training, they used the following airports: Condon (S04), Meadow Creek (0S1), Spotted Bear (8U4) and Schafer (8U2). The instructor stated that the pilot met and exceeded "every minimum requirement." The pilot successfully completed the required check ride in a Cessna 182 on May 13, 2004, and was approved to act as pilot in command of Cessna 182 and Cessna 206 airplanes operated by Edwards Jet Center under 14 CFR Part 135. On June 14, 2004, the pilot received an Interagency Airplane Pilot Qualification Card after satisfactorily completing a 1.8 hour evaluation check ride in the accident airplane. The card authorized the pilot to act as pilot in command of Cessna 182 and Cessna 206 airplanes carrying federal employees in day VFR conditions on point to point, air tactical, fire surveillance, reconnaissance and mountain flying/unimproved strips missions. According to a written statement by the USFS pilot who performed the evaluation, the pilot's "performance was comparable" to that of other pilots to whom he had given evaluation rides. On the Airplane Pilot Qualifications and Approval Record (USFS Form FS-5700-20) completed by the pilot on June 14, 2004, he listed 285 hours pilot in command (PIC) time in Cessna 182 airplanes and 7 hours PIC time in Cessna 206 airplanes. In the block titled, PIC "Typical Terrain" (Over Mountains), the pilot listed 100 hours. In the block titled, PIC "Low Level" Op[eratio]ns (-500' AGL), the pilot listed 250 hours. According to documents provided by the USFS, for a pilot to be carded by the USFS, that pilot must meet specific minimum flying experience requirements. These requirements include 25 hours as PIC in make and model to be flown and 200 hours as PIC conducting operations in typical terrain. The documents did not provide a definition of typical terrain. The USFS pilot who performed the evaluation check ride stated that he was not able to review the pilot's logbook; however, he did question the pilot about his hours as PIC in make and model and in typical terrain. The accident pilot responded that he had 60 hours flight time in Cessna 210 airplanes, and the USFS pilot accepted this time as applicable to the make and model requirement since it was in "a 200 series Cessna aircraft." He further responded that he was confused by the wording on the form and that he assumed his 250 hours as PIC in low level operations applied to his flying in mountainous terrain. He also stated that to him typical terrain over mountains meant flying over mountains at altitudes several thousand feet above the highest point. The USFS pilot questioned the accident pilot further and after the accident pilot "described the areas where he had flown with privately owned aircraft, and the practical training he had received from experienced Edwards Jet Center pilots in backcountry takeoffs, landings and point to point flying," he "felt confident" that the accident pilot met the requirements. The USFS pilot stated that the definition of typical terrain over mountains "is open to interpretation to pilots throughout the agency." Review of the pilot's personal flight logbook indicated that the last entry had been made on September 18, 2004. As of that date, the pilot had accumulated 2,723 hours total flight time of which 15 hours were in a Cessna 206. The pilot's logbook did not include a specific record of back country or mountain flying experience. It did include specific records of the pilot's flight time for Edwards Jet Center, 35 hours, and for the Civil Air Patrol, 94 hours. Logbook entries dating from September 2002 to September 2004 were reviewed, and there were a total of 15 entries involving a total flight time of 14 hours that included a takeoff or landing at any of the four mountainous airports identified by the instructor who provided the pilot's Part 135 flight training. Seven of the entries recorded an operation at Schafer airstrip. The most recent entries indicated the pilot had landed at Schafer twice on September 10, 2004 and twice on September 12, 2004; these landings were made in the accident airplane. AIRCRAFT INFORMATION Examination of the airplane's maintenance records indicated that the 1982 model Cessna Stationair 6 received its most recent annual inspection on August 3, 2004, at a total airframe time of 4,224 hours. As of that date, the engine, a Continental IO-520-F, S/N 574383, had accumulated 1,290.8 hours since overhaul. Review of the maintenance records revealed no evidence of any uncorrected maintenance discrepancies. The airplane was equipped with a King KLX-135 GPS COM. This unit had no capability to show terrain on a moving map display. The airplane was not equipped with automated flight following equipment, nor was this required. The airplane was inspected by a USFS aircraft inspector on May 25, 2004. The inspector approved the airplane for public use passenger, cargo, fire surveillance/reconnaissance and air attack flights. Although the airplane was certified by the FAA to carry 5 passengers, the inspector approved the airplane for 3 passengers. The inspector stated that his reason for limiting the number of passengers was that at the time of his inspection there were only 3 seats installed in the airplane. He further stated that he called his supervisor and was advised by the supervisor "to enter 3 on N206SMs aircraft data card for the number of passenger seats that were actually installed in the aircraft." The weight and balance of the airplane at takeoff was estimated using the following information: basic empty weight 2,107 pounds, front seat occupants 484 pounds, middle seat occupants 290 pounds, rear seat occupant 130 pounds, rear seat baggage 100 pounds, aft baggage 125 pounds, fuel 300 pounds (50 gallons). The estimated takeoff weight was 3,536 pounds, which was below the maximum gross weight of 3,600 pounds. The estimated takeoff moment was 169.6/1000 (pound-inches/1000), which was within the allowable moment range for the calculated takeoff weight. (At 3,600 pounds, the allowable moment range is 153.0/1000 to 178.9/1000.) METEOROLOGICAL INFORMATION The surface analysis chart prepared by the National Weather Service (NWS) for 1500 on September 20, 2004, showed a weak trough of low pressure over northwestern Montana. Pertinent surface weather observations for the Glacier Park International Airport, in part, follow: At 1155, the reported weather conditions included wind from 140 degrees at 3 knots; visibility 10 miles; present weather none; sky condition broken 500 feet, broken 800 feet, overcast 3,300 feet; temperature 8 degrees Celsius; dew point 6 degrees Celsius; altimeter setting.29.99 inches hg; remarks none. At 1255, the reported weather conditions included wind from 130 degrees at 8 knots; visibility 10 miles; present weather none; sky condition scattered 1,300 feet, broken 3,300 feet, overcast 4,500 feet; temperature 9 degrees Celsius; dew point 6 degrees Celsius; altimeter setting 30.00 inches hg; remarks none. At 1335, the reported weather conditions included wind from 310 degrees at 4 knots; visibility 1 3/4 miles; present weather heavy rain, mist; sky condition broken 1,900 feet, overcast 3,400 feet; temperature 7 degrees Celsius; dew point 5 degrees Celsius; altimeter setting 30.02 inches hg; remarks rain began 1306. At 1355, the reported weather conditions included wind from 150 degrees at 9 knots; visibility 10 miles; present weather none; sky condition broken 1,900 feet, overcast 3,400 feet; te

Probable Cause and Findings

The pilot's misidentification of the airplane's location, which resulted in his improper decision to fly into the wrong drainage, and his failure to maintain terrain clearance while executing a turn to reverse course after he realized his navigational error. Contributing factors were the low visibility due to mist, obscuration of the mountainous terrain, and the pilot's lack of experience in back country flying.

 

Source: NTSB Aviation Accident Database

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