SEA02TA110
SEA02TA110

HISTORY OF FLIGHT

On June 25, 2002, at 1556 Pacific daylight time, a Bell 206B, N1087L, registered to Aero Copters and operated by the National Park Service as a public use flight, collided with the terrain on Mount Rainier, Rainier, Washington. Visual meteorological conditions prevailed and a company visual flight rules flight plan was in effect. The helicopter was substantially damaged and the commercial pilot and two passengers were not injured. The flight originated from Seattle, Washington, with two stops on Mount Rainier before proceeding to the Carbon Glacier located on the northern face of Mount Rainier.

During an interview with the pilot, he reported that Aero Copters was contacted to dispatch a helicopter to the Kautz helibase at Mt. Rainier. The pilot's trip records indicated that the flight departed Boeing Field, Seattle, Washington, at 1315, and arrived at Kautz helibase at 1355. At the helibase, the pilot was given a briefing and issued a mission to take one climbing guide from the Kautz helibase and pickup a National Park Ranger from Camp Schurman. The mission was to then proceed to the Carbon Glacier to drop off the guide and the ranger to aid in the rescue of an injured hiker. Earlier in the day, an Army CH-47 (Chinook) had hoisted in two other Park Service personnel to about the 9,200 foot level to assess the hiker's injuries and provide medical attention. The injured hiker was located between 10,000 to 10,400 feet.

The pilot reported that prior to departing Kautz helibase, he completed a "load calculation," which indicated that the results of the calculations were at the high end, but within operating parameters. The Load Calculation form was signed off by both the pilot and the helicopter manager. At 1518, the helicopter departed from Kautz helibase with the climbing guide and proceeded to the west side of the mountain in order to survey the landing site at Carbon Glacier. The pilot stated that he made about three passes to orient himself to where the injured hiker was located, and to the potential landing sites as well as checking helicopter performance for that elevation. He then proceeded to Camp Schurman to pick up the climbing ranger. The flight arrived at Camp Schurman, however, the climbing ranger was above Camp Schurman at Emmons Flats where he had prepared a landing zone. The pilot repositioned the helicopter and the climbing ranger boarded the helicopter, sitting in the left rear seat behind the climbing guide in the front left seat. The flight departed Emmons Flats at 1540.

Upon reaching the Carbon Glacier, the pilot flew over the site where the injured hiker and previously inserted ground party were located, then proceeded to the landing spot suggested by the ground party. The pilot stated that he hovered in close to the spot and attempted to land but then decided that he did not like this spot and repositioned lower down the hill. A landing was made at this lower location. The pilot reported that the climbing party then radioed him and asked if he could reposition higher up the hill. The pilot stated that he still had "plenty of power reserve" and took off again. The pilot found a spot that he believed was used by the Chinook earlier in the day. The pilot hovered over the spot, however, there were crevasses and cracks in the snow in close proximity to the landing spot. The pilot chose another spot and set down slowly on the snow with the helicopter facing upslope. The pilot slowly lowered the collective and moved the pedals to test the compaction of the snow with the landing skids. The pilot stated that at this point he did not believe that the collective was all the way down when the helicopter suddenly pitched and he applied forward cyclic control. When questioned as to which direction the helicopter "pitched," the pilot reported that, "I think I believe that the tail pitched down more than the nose pitched up." "It felt like the back end fell more than it felt like the nose came up." The pilot stated that he thought that he had reached the droop stop limit because the helicopter "had that kind of hopping vibration." The pilot applied forward cyclic and raised the collective to lift off the snow. The helicopter started to yaw to the right and he applied left pedal input which did not have any effect. The pilot realized that he had no tail rotor control and lowered the collective and the helicopter impacted the glacier with no additional movement and the nose pointing downhill, 180 degrees from the initial landing heading.

The front seat climbing guide reported that he met the pilot at the Kautz helibase. The guide did not receive a full briefing of the mission, but it was his understanding from a discussion with the Air Mission Advisor that he was going on the helicopter in order to help the pilot locate the site where the injured hiker and ground crew were, help the pilot find his way around the mountain, and that the pilot needed somebody experienced onboard to tell him where they were going. After the safety briefing at the helicopter, the pilot and climbing guide had a brief discussion as to which way around the mountain they would go to get to Camp Schurman. It was decided to go around to the west side in order to look at Carbon Glacier where the ground team was located on Liberty Ridge before proceeding to Camp Schurman to pick up the climbing ranger.

The site was located and the pilot flew low over the area. The guide stated that communications with the pilot were a bit difficult because he was not provided with a flight helmet compatible with the aircraft's avionics. The guide had to listen through his flight helmet and talk through a headset microphone. Because of the difficulties the guide was having communicating, he was not sure if the pilot intended to land and drop him off at the Carbon Glacier, or proceed to Camp Schurman to pick up the climbing ranger. Since the pilot was on his first trip to Mount Rainier and didn't know the location of Camp Schurman, the climbing guide told the pilot that they needed to go to Camp Schurman to pick up the climbing ranger. They then proceeded to Camp Schurman to pick up the climbing ranger. Without shutting down, the climbing ranger boarded the helicopter and was seated directly behind the front seat guide. The front seat climbing guide stated that later he found out that the climbing ranger was more experienced in helicopter operations and should have been seated in the front. It was also learned that the climbing ranger did not have a flight helmet available for intercom communications, and was only wearing his climbing helmet.

The flight then continued to the site. The climbing guide stated that the pilot circled around the site then the pilot pointed to an area where he would have liked to land. The climbing guide stated that this was in the fresh avalanche debris of the main stream of debris and it was his opinion that the pilot did not understand the glacier and the hazards of the mountain. The climbing guide instead pointed the pilot to the spot where the Chinook had hoisted in the ground crew. This spot looked to the climbing guide to be the most level. The area was near a large crevasse and a plug of ice bridging it. The pilot started to put down in this spot then pulled off and did not land. The pilot instead repositioned several hundred feet lower and landed.

After some communication with the ground party to see if the pilot could reposition higher, the pilot took off and repositioned higher up the mountain and landed to one side of a crevasse, but the climbing guide saw cracks in the surface and said that he could not get out safely without being properly secured (roped). The pilot then lifted the helicopter up and repositioned to the spot he originally tried to land but didn't touch down on. The spot was just below the crevasse and the slope was on a slight angle. The pilot positioned the helicopter pointing straight into the hill and slowly touched down. The guide stated that "There would already be a little bit of an angle with the tail down and the nose up because of the slope angle, but it seemed like we took on more of an angle, with the nose up and the tail down and my impression was that the skids of the helicopter must have been sinking into the snow farther at the tail than at the nose because our angle did not fit the slope angle." The guide stated that although the pilot was being careful, it seemed like the tail was getting too far down. The guide stated, "...we heard the tail rotors hitting the glacier, you know, a hard shutter of the helicopter and a noise you know WHACK, WHACK, WHACK hitting hard." At that point, the pilot pulled the helicopter up which started a slow turn at first, then spun violently before impacting on the glacier with the nose pointing down hill.

The climbing ranger stated that after he boarded the helicopter, they took off to the site. As stated earlier, he did not have a flight helmet and was unable to use the headset with his climbing helmet. The climbing ranger stated that the pilot flew over the area and tried a spot to land, but backed out. The pilot circled around a couple more times. At this point, the climbing ranger tapped the front seat passenger on the shoulder and told him to go about 1,000 feet lower to a landing zone about the size of half a football field that was level. The pilot positioned about half the distance down the hill to where the climbing guide said. The pilot chose a spot that was about a 5 degree slope and "full of avalanche debris, icy in spots, soft mounds in spots, really pretty level but bumpy." The helicopter touched down momentarily then lifted back up. The pilot tried another spot with similar conditions. The tail rotor was away from the mountain, but close to obstructions. The climbing ranger again tapped the front guide on the shoulder to tell the pilot to watch the tail. The pilot lifted the helicopter back up and went back to the original spot, then moved over about 10-20 feet. The pilot nosed into the mountain and gently set the helicopter down and proceeded to try and pack the surface down. That is when the climbing ranger felt the helicopter tilt backwards slightly and slide down the hill. The pilot immediately lifted the helicopter into the air and it started to rotate clockwise. The climbing ranger assumed the crash position until the helicopter impacted the glacier, coming to rest with the nose facing downhill.

When questioned as to the slope of the terrain where the pilot was trying to land, the climbing ranger stated that the surface was level from the aft skid cross tube forward. From the aft cross tube rearward, the terrain sloped down about 5 degrees. The climbing ranger stated that when the helicopter slid backward, it felt like it bumped into something.

One of the rescue personnel with the injured hiker, located about 500 feet above the accident site stated that he was in direct communication with the pilot and was watching the helicopter the entire time. The rescuer stated that he was trying to direct the pilot to the best landing zone. Several attempts were made before the pilot set down at a spot with the nose facing directly uphill. The rescuer stated, "He was directly into the slope - facing directly uphill, which when I originally had envisioned the landing zone there I thought he would want to land his helicopter perpendicular to the hill...sideways to the hill. It seemed like a better egress that way - a 90-degree turn instead of a 180-degree turn to get out of that situation if something went wrong." The rescuer also stated, "I kept trying to direct him a little bit closer to the east. And, he was not more than 20 to 40 feet away from where I thought would have been the best spot. Now, the reason I thought he would land perpendicular to the slope is that your skids are basically like skis and if you land with your skids perpendicular or side-hill you know you're not in jeopardy of the helicopter actually sliding down the slope once you weight the skids." The rescuer stated that it appeared that the pilot was putting weight on the skids when the helicopter suddenly slid backwards. The helicopter lifted off, attaining an altitude of about 10 feet off the ground and started to rotate clockwise. The rescuer did not see any part of the helicopter hit the ground, but it did rock backwards with the tail rotor downhill and close to the ground. The helicopter continued to rotate and eventually impacted the glacier with the nose facing downhill.

PERSONNEL INFORMATION

The pilot held an airline transport pilot certificate for multi-engine land aircraft and commercial and flight instructor certificates for single-engine land airplane, helicopter and glider operations. The pilot reported a total flight time of 6,851 hours in all aircraft, with 2,395 hours in rotorcraft. Approximately 862 hours were reported in the make and model helicopter involved in the accident.

During the pilot's interview, he indicated that he had worked two fire seasons that involved high density altitude activity. The pilot reported that this was the first time that he had worked on Mt. Rainier.

The pilot held a USDA-USDI Interagency Pilot Qualification Card that indicated the operations the pilot is authorized to perform. The card indicated that the pilot was signed off for "mountain flying." The pilot was not signed off for "snow operations (deep snow)." A representative from the Department of the Interior, Office of Aircraft Services reported that "snow operations" referred mainly to powder or soft surfaces and the potential for white-out conditions.

The card also indicated that the pilot was approved to fly interagency missions for Northwest Helicopters. The pilot did not have an interagency Pilot Qualification Card authorizing him to fly missions for Aero Copters.

WRECKAGE AND IMPACT INFORMATION

Aerial photographs of the accident site indicated that the helicopter impacted the glacier between two crevasses. The accident site elevation was estimated about 8,800 feet at 46 degrees 52.52 North latitude, 121 degrees 46.17 West longitude. Photographs taken by the ground parties indicated that the helicopter remained upright with the landing skids buried in the snow. The main rotor blades separated at approximately the mid span point. The tailboom bent forward to the left side of the fuselage, blocking the left side aft door from being able to open. The transmission displaced forward and crushed downward about one foot, compromising the cabin area. Some hydraulic fluid spilled out onto the rear seat climbing ranger. The tail rotor blades indicated that one blade was intact and the other blade separated approximately two inches outboard of the hub.

ADDITIONAL DATA/INFORMATION

The National Transportation Safety Board (NTSB), Investigator-In-Charge, authorized the owner/operator to recover the helicopter as soon as practical. Several days after the accident, the NTSB was notified that the helicopter had not been recovered before the wreckage was lost in a crevasse and covered by snow and rock fall.

Department of Interior contractual procedures require that the U.S. Department of the Interior Helicopter Load Calculation form 67 be completed prior to a mission. This form is a tool used to predict the aircraft's load carrying capability under the environmental conditions the helicopter is operating. By contract, the pilot is responsible for completing lines 1-13, the helicopter manager completes lines 14-16. Both pilot and helicopter manager sign the form.

After the accident, Form 67 that was prepared for the mission by the pilot was retained for review (see attached Form 67). The form indicated that a pressure altitude of 9,000 feet and 10 degrees Celsius were used. A 2,950 pound computed gross weight (line 7) was indicated for out of ground effect. Adjusted and fixed weights calculated an allowable payload (line 13) of 510 pounds. The actual payload (line 15) for both passengers and the oxygen pack totaled 490 pounds. The operating weight (line 6) was computed as 2,310 pounds plus the payload weight of 490 pounds totaling an actual gross weight (line 16) of 2,800 pounds. The form indicated that the actual gross weight is not to exceed the selected weight (line 11). The form indicated that the selected weight was 2,820 pounds.

After the accident, two load calculations were prepared by the Air Safety Investigator participant from the Office of Aircraft Services for hover ceiling out of ground effect operations (see attached Load Calculation by OAS). A pressure altitude of 8,800 feet (approximate accident elevation) and 13 degrees Celsius (temperature indicated by the CH-47 pilot and temperature that was given to the pilot during the briefing) was used. Two load calculations were created to indicate the weights for operations in the critical relative wind azimuth Area A and Area B (see attached Figure 4-5).

The first calculation for Area A indicated a computed gross weight of 2,625 pounds and an allowable payload of 205 pounds. The operating weight was computed as 2,290 pounds plus the actual payload of 490 pounds totaling an actual gross weight of 2,780 pounds. The selected weight indicated 2,495 pounds. (see attached Area A Calculation)

The second calculation for Area B indicated a computed gross weight of 2,850 pounds and an allowable payload of 430 pounds. The operating weight was computed as 2,290 pounds plus the actual payload of 490 pounds totaling an actual gross weight of 2,780 pounds. The selected weight indicated 2,720 pounds. (see attached Area B Calculation)

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