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On August 31, 2010, about 0929 Pacific daylight time (PDT), a Hiller UH-12E helicopter, N67264, was substantially damaged when it impacted utility lines, a travel trailer, and the ground in Kamiah, Idaho, about 35 minutes after departure. The commercial pilot and the two passengers, both of whom were biologists with the Idaho Department of Fish and Game (IDFG), were fatally injured. The helicopter was owned by Leading Edge Aviation (LEA), and was under the operational control of IDFG as a wildlife survey flight. The flight was conducted under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91, and in accordance with the IDFG Clearwater Region "Regional Summary of Procedures for Monitoring Low Level Aerial Survey Operations," dated December 31, 2009. Visual meteorological conditions prevailed. A notification for automated flight following (AFF) was filed and activated with the Idaho State Communications Center, referred to as "StateComm."
The biologists arrived at the LEA helicopter base, Skid Row Seaplane Base (WT33) Clarkston, Washington, about 0800. Flight preparations and briefings were conducted, and most of the biologists' gear was secured in cases on external racks on the helicopter. The plan was for the helicopter to fly about 70 miles to the east to rendezvous with an LEA fuel truck, refuel, and then conduct the survey. The pilot seated himself in the center seat, the female biologist was in the right seat, and the male biologist was in the left seat. The helicopter departed WT33 about 0850, and the first AFF return from the helicopter was received about 6 minutes after that. About 33 minutes later, StateComm received a radio call from the helicopter, announcing that it intended to land in Kamiah. No explanatory or additional transmissions were received from the helicopter.
Kamiah was a small town situated about 30 miles short (west) of the planned fuel stop. Several eyewitnesses in Kamiah reported that they first observed the helicopter transiting west to east. They then heard unusual noises emanating from the helicopter, and observed objects separating or falling from the helicopter. Several noted that the helicopter was gyrating or rotating about its longitudinal or vertical axes, and that the trajectory steepened as the helicopter descended. The main wreckage, which consisted of the cabin, tail boom and main rotor system, impacted in a driveway of a residence. Two of the occupants received immediate fatal injuries, while the third survived for several minutes after the impact.
A debris path that was oriented back (west) along the helicopter's flight path, and that measured approximately 1,500 feet in length, was comprised of various items from the helicopter. Some of the earliest items in the debris path included the tail rotor blade and tail rotor gearbox segments, and fragments of a metal clipboard that belonged to one of the biologists.
The pilot was an employee of LEA. He held a commercial pilot certificate with a helicopter rating. According to information provided by LEA, he had approximately 9,000 total hours of flight experience, all of which was in helicopters, and which included approximately 300 hours in the accident helicopter make and model. His most recent flight review was completed in October 2009, and his most recent Federal Aviation Administration (FAA) second-class medical certificate was issued in October 2009.
The Lewis County (Idaho) Coroner's Office autopsy report indicated that the cause of death was "blunt force trauma." The FAA Civil Aeromedical Institute conducted forensic toxicology examinations on specimens from the pilot, and reported that no carbon monoxide, cyanide, ethanol, or any screened drugs were detected.
According to IDFG information, the pilot was properly "carded" (trained and approved by the Aviation Management Directive (AMD) of the National Business Center (NBC) of the United States Department of the Interior, in accordance with IDFG contractual requirements) and was current with regard to all other IDFG qualifications. The flight was the first scheduled flight of the day, and the pilot was within the duty day and other crew requirements or limitations established by the contract. The pilot and both biologists were wearing the required aviation life support equipment at the time of the accident. Both biologists were current with respect to their IDFG-required aviation safety training, and both had an extensive history of low altitude flights.
The male biologist was a private pilot with approximately 10 years of flight experience, and owned a single-engine airplane. He also had about 10 years of experience with the same type of survey that was planned for the accident flight; most of those flights were conducted in helicopters.
Also according to IDFG information, the female biologist had conducted extensive low-altitude fixed-wing survey flying between the years 2000 and 2004. It was reported by some IDFG personnel that she may have been susceptible to airsickness, but no definitive evidence or documentation of this was provided for the investigation.
Autopsies were not conducted on either biologist.
According to FAA records, the helicopter was manufactured in 1965, and was converted to turbine power in 1981. Information provided by LEA indicated that at the time of the accident, the helicopter had accumulated a total time (TT) in service of 7,388 hours. Review of maintenance records indicated that the most recent annual inspection was completed in April 2010. At that time, the airframe had a TT of 7,168 hours, while the engine had a TT of 7,432 hours. The most recent 100-hour inspection was completed in July 2010, and the helicopter had accumulated about 80 hours in service since that inspection.
General Configuration Information
The basic configuration consisted of 3-place-abreast seating in a metal-frame and plastic transparency "bubble cabin," a two-bladed metal main rotor, and a two-bladed metal tail rotor (painted red). Specific configuration details included:
- A metal "seat deck"' which was the primary structural element of the cabin
- Metal-framed left and right side cabin doors
- A vertical firewall that also served as the aft cabin wall
- A central pilot's seat with an instrument/control pedestal, and flight controls
- Left and right external racks (approximately 6 feet long, 2 feet wide, and 4 inches deep, with metal mesh bottoms)
- Main rotor rotation counter-clockwise when viewed from above
- A metal, semi-monocoque tail boom
- Multi-segment tail rotor drive system mounted atop the tail boom
- Tail rotor gearbox at the aft end of the tail boom
- Tail rotor rotation counter-clockwise when viewed from helicopter left side
- Single metal horizontal stabilizer on the right-side end of the tail boom
The 1030 automated weather observation at Kamiah Municipal Airport (S73), Kamiah, included calm winds; clear skies; temperature 16 degrees C; dew point 10 degrees C; and a barometric pressure of 29.99 inches of mercury. Visibility values were not recorded, and no precipitation was recorded in the 12 hours preceding the accident.
AIDS TO NAVIGATION
A handheld Garmin GPSMap 396 global positioning system (GPS) unit was found in the main wreckage, and mounting, antenna, and power provisions for the unit were attached to the helicopter. The unit was recovered and shipped to the NTSB Recorder Laboratory in Washington DC. Data downloaded from the GPS unit indicated that a pre-stored route entitled "Skid Row - S73" was active for the flight.
According to its website, StateComm was an emergency communications center that operates continuously, to provide emergency dispatch and communications for State and public health- and safety-related situations or emergencies. Partner agencies included the Idaho Transportation Department, Idaho State Police, and IDFG.
The StateComm network had provisions for both automated tracking of subject aircraft, as well as radio voice communications between the aircraft and the network personnel/offices. Typically, aircraft operating on missions of concern to StateComm were monitored via the AFF system, which was a GPS and satellite/web-based system whereby the dispatcher could monitor an aircraft via computer in real time; data associated and presented with the aircraft icon included aircraft location, speed, heading, altitude, and flight history. The StateComm AFF system required dedicated hardware on the aircraft, and required each AFF/ GPS unit to be set up so that it would automatically broadcast aircraft position data at an interval of once every 2 minutes.
The aforementioned IDFG Clearwater "Procedures Summary" stated that "AFF should be used whenever possible" for IDFG survey flights, and recommended the use of StateComm for AFF services. Filing and activating AFF was the responsibility of the "individual responsible for initiating the survey." The Procedures Summary stated that the "flight follower must be contacted when taking off and at least every 30 minutes following, or whenever a major change in flight location is taking place. Flight follower must be informed of every landing and takeoff unless other arrangements have been made. Flight follower must be contacted when flight is terminated. If the aircraft fails to make contact within one-half hour of the scheduled time, the flight-following service will initiate a search and rescue operation."
StateComm Documentation Time Discrepancies
The investigation was provided with two documents and one position data file by StateComm regarding the accident flight. The document entitled "Flight Following Incident" contained the AFF-related information for the flight, while the other one ("M-2010-00070") chronicled the StateComm ground-based communications regarding the flight. The data file contained 6 flight data points, and each data point included position and time information. All "time" information was manually entered by StateComm personnel. Both documents contained multiple entries with "time" information, but neither contained any reference to a particular time zone. In addition, both documents contained internal contradictions regarding "time;" the "creation" or "print" times were prior to some of the event time stamps on the documents. However, the data file did specify time zone references. Since StateComm was based in Meridian, Idaho, which was in the mountain time zone, and the accident flight took place in the Pacific time zone, the time stamps associated with the flight itself were presumed to be stated in mountain time, which placed them in alignment with the times in the data file.
Accident Helicopter StateComm Communications
According to the StateComm "Flight Following Incident" printout for the accident helicopter, an "AFF active" communication was received from the flight at "1004" (0904 PDT), and the transmitted geographic coordinates indicated that the helicopter was 10.6 nm, on a bearing of 093 degrees true, from WT33. At "1029," (0929 PDT) a "landing in Kamiah" communication was received from the flight. The StateComm geographic coordinates associated with that broadcast indicated that the helicopter was 11.6 nm, on a bearing of 293 degrees true, from the accident location. Review of available data indicated that that position for the "landing" radio call was not valid.
The time specified in the StateComm AFF synopsis document for the "landing" radio call was 0929 (adjusted to Pacific time zone), which was also about the same time as the last GPSMap-recorded time, and very close to the time of the accident. Further evaluation of the data revealed that the position data associated by StateComm personnel with the "landing" call was actually the last AFF position data that had been received from the helicopter, and was at least 6 minutes old, and the position Since the actual AFF position interval was incorrectly set (see following paragraphs), that last position data was significantly older/less current than it was supposed to be. However, since it was still the most recent data available to StateComm, it was utilized as the position location for the "landing" call, which conflicts with other position and time information regarding the flight.
According to a representative of the Aviation Management Directive (AMD) of the National Business Center (NBC) of the United States Department of the Interior, the StateComm records provided to the investigation were the only records available. Therefore, neither the exact time, nor the exact location of the helicopter for the "landing in Kamiah" radio call could be determined.
StateComm document M-2010-00070 indicated that about "1045," (0945 PDT) a representative of LEA telephoned StateComm to confirm that StateComm was "flight-following" the helicopter. When StateComm responded that it was following the helicopter, the LEA representative informed StateComm that "the helicopter was no longer active on AFF" for LEA. StateComm then informed LEA that the pilot radioed that he was landing in Kamiah, and that the AFF data icon at StateComm was "red," which indicated that it was more than 15 minutes since StateComm had received any position information from the helicopter. Subsequent attempts by StateComm, at the request of the LEA representative, to communicate with the helicopter were unsuccessful. About "1058," (0958 PDT) the Lewis County Sheriff office notified StateComm that a helicopter with registration N67264 had crashed in Kamiah, and that there were two fatalities.
Review of IDFG guidance regarding flight following procedures revealed that once airborne, IDFG flight personnel were required to notify StateComm whenever they intended to change the route of flight, or conduct a landing at a location other than that originally specified. However, the guidance did not require the provision or solicitation of any additional amplifying information, such as the reason for, or the timing of, the changes. The guidance also required flight personnel to notify StateComm after every landing, but the guidance did not specify a time window (after the landing) for the notification.
Helicopter AFF Data Transmission Interval
Post-accident examination of the AFF position tracking data from the accident helicopter revealed that its AFF/GPS unit had remained set to the manufacturer's default broadcast interval setting of 6 minutes, instead of the 2-minute interval specified as an IDFG contractual requirement. According to the AMD/NBC representative, resetting of the broadcast interval to the StateComm standard was the responsibility of the aircraft operator. It could not be determined why LEA did not reset the accident helicopter's AFF/GPS broadcast interval.
WRECKAGE AND IMPACT INFORMATION
The area immediately surrounding the main wreckage impact site was residential. The impact site was located about 1 mile northwest of S73. The overall debris field extended approximately 1,500 feet, with a primary axis from west to east. The main wreckage was situated in a compact area surrounded by tall trees and utility poles. The trees, approximately 60 feet tall, and approximately 15 to 20 feet from the main wreckage, had no significant signs of damage. The helicopter tail boom impacted a travel trailer parked in a driveway, and one main rotor blade sliced completely through the trailer. The engine remained attached to its mounts. The transmission, mast and both main rotor blades were present at the main wreckage site. The tail boom was angled about 40 degrees aft-end up, and the aft end rested on the travel trailer. Its forward end remained attached to the helicopter structure. The canopy frame and transparencies were fracture-separated into multiple pieces; many were found forward of the cabin.
Lewis County Sheriff (LCS) personnel, in conjunction with IDFG and Idaho Department of Lands (IDL) personnel, located, mapped with GPS, and recovered the wreckage components from the outlying debris field. The items were then transferred to the NTSB investigators at the main wreckage location, where they were identified and catalogued into a database. Review of the wreckage components and the database revealed that all components of the helicopter were successfully recovered.
The damage to the main wreckage was consistent with a high velocity, near-vertical trajectory. The cabin was found essentially upright, but heavily damaged. The damage patterns to the seat deck, pedestal, instrument panel, engine mounts and skid gear were all consistent with lateral loading from the right. Ground scars were consistent with minimal travel to the right. The main rotor blade that cut through the travel trailer was angled about 30 degrees from a horizontal ground plane, consistent with a right-side-down impact attitude
Each of the three seats was equipped with a multi-point restraint system, with a rotary buckle and an inertia reel. The lock and release functionality of each inertia reel was manually confirmed on site. The restraints all appeared to be in good condition, and no failures were evident. According to first responders, all three persons were properly secured by their restraint systems, all remained in their seats, and each wore a flight helmet.
The helicopter's lead-acid storage battery, mounted forward of the instrument panel, was found about 600 feet south of the debris field axis, and about 300 feet west-southwest of the main wreckage.
The two cabin doors were each equipped with two separate and independent operating mechanisms. At the forward edge of each door was a quick-jettison system to rapidly separate the door from the cabin structure. At the aft edge of each door was a latch mechanism for normal (hinged) operation of the door, to permit crew entry and exit. The doors were hinged to the cabin at their forward edges.
The quick-jettison handle for each door was in place, and undisturbed/unused.
The two doors exhibited moderately different damage patterns. The left door exhibited crush and folding damage, but remained attached to the cabin structure. The right door was found nearly intact, with some crush damage to its lower portion, and was fracture-separated from the cabin structure.
The left door strike plate/latch capture mechanism remained attached to the cabin frame, and appeared undamaged. The left door handle/latch remained attached to the left door, and did not exhibit any significant damage. Investigators first observed the left door handle one day after the accident, and it was found to be in the "open" position. The handle was free to rotate between the "open" and "close" positions. No information regarding the position of the handle immediately after impact was available.
The right door strike plate/latch capture mechanism also remained attached to the cabin frame, but its tab was bent approximately 100 degrees forward/outboard. The right door handle/latch remained attached to the right door, and did not exhibit any significant damage. Investigators first observed the right door handle one day after the accident, and it was found to be in the "open" position. The handle was free to rotate between the "open" and "close" positions. No information regarding the position of the handle immediately after impact was available.
The fuel caps remained securely mounted in their respective receptacles in the main and auxiliary tanks. The fuel lines remained attached to the auxiliary fuel tanks. The main bladder tank was compromised by downward penetration of the engine support structure and the lower transmission. The tank was devoid of fuel when examined the day after the accident. Both auxiliary tanks were ruptured, consistent with hydraulic deformation, and both were devoid of fuel when examined the day after the accident.
Main Rotor System
All portions of the main rotor system and its controls were found at the main wreckage location. The helicopter was configured to accommodate dual (center and left-side) flight controls, however, the left side controls were not installed. The center-seat cyclic and collective controls were installed. Control continuity was established for both the collective and cyclic systems. Both systems had multiple overload failure sites, consistent with ground impact damage.
Tail Boom and Tail Rotor System
The tail boom, tail rotor drive system, tail rotor control system and tail rotor were fragmented into numerous segments. The tail rotor and tail rotor gearbox were among the earliest (westernmost) components in the debris field. The aft section of the tail boom was fracture-separated approximately 2 inches forward of the aft-most tail rotor drive pillow block. Damage patterns were consistent with one or more main rotor blade strikes on the tail boom. The Hiller representative noted that in-flight loss of the tail rotor and horizontal stabilizer could result in a rapid nose-down pitching motion, and consequent main rotor strikes to the tail boom.
The tail rotor drive system consisted of a two-segment drive shaft and a gear box. The forward drive shaft segment was found essentially intact at the main wreckage site, but fracture-separated from the helicopter. The aft drive shaft segment was found fracture-separated into four sections. These fragments were found in the large debris field. The damage patterns at the aft drive shaft fracture-separation sites were consistent with torsional failure, main rotor blade impact, or both. No damage consistent with failure of any tail rotor drive shaft element due to pre-existing conditions was observed.
The tail rotor was found in three main pieces; the central hub with blade roots, and the two outboard blade segments. Each outboard segment was approximately 18 inches long. The tail rotor hub and yoke assembly remained attached to the tail rotor gearbox, but the gearbox was fracture-separated from the tail boom. Witness marks, including a conforming sized- and shaped-dent, and red paint transfer, indicated that the gearbox moved down and to the right and struck the top outboard surface of the horizontal stabilizer. The fracture surface of the separation that liberated the gearbox was consistent with one-time overload, with no evidence of pre-existing damage such as fatigue striations or corrosion. The gearbox, hub assembly, and tail rotor blade fragments were some of the earliest (western-most) components in the debris field.
One tail rotor blade exhibited significant leading edge crush damage in the chordwise direction, from leading edge to trailing edge. The crush damage was present on both the root and liberated segments of that blade, which was consistent with the crush damage occurring before the blade fracture. The crush damage and paint color were consistent with damage to one section of the metal clipboard/case that was found in a similar location in the debris field.
The helicopter was equipped to accommodate two sets of anti-torque pedals, but only the center (pilot's) set of pedal bars was installed for the flight. The pedals were partially free to move, but full travel was restricted by crush damage to the forward fuselage. Continuity was established between the center and left-side pedal mechanisms in the cockpit. The tail rotor pitch change mechanism was intact, and remained attached to the hub and yoke assembly. However, full anti-torque control continuity could not be positively established due to the damage to the system. All components were accounted for in the wreckage.
The helicopter was powered by an Allison Engine Company model 250 C20 gas turbine engine, and had a total time in service (TT) of approximately 7,653.0 hours. The engine was installed on the accident airframe October 14, 2008, when the engine had a TT of 7,087.4 hours. Review of maintenance records for the 30 days prior to the accident indicated that there were no reported engine discrepancies.
The factual information obtained during the on-scene examination of the engine resulted in the determination that the engine would not require additional examination. All findings from the on-scene examination were consistent with normal operation of the engine during the flight and through the descent and ground impact.
The engine mounting framework fractured in several locations, but the engine remained essentially in its normal position. The only impact damage noted to the engine was denting to the outer combustion case dome. All other engine components and hardware were in place and properly secured. Control arms on the power turbine governor and the fuel control unit were free to move through their entire travel ranges.
Visual examination of the compressor revealed significant foreign object impact damage to the first and second stage axial blades and vanes, and the blades were bent in the direction opposite of rotation. All inlet guide vane trailing edges exhibited bending in the direction of compressor rotation, which was consistent with foreign object ingestion. The N1 drive train could not be manually rotated due to compressor blade and vane damage. The N2 drive train was manually rotated at the T4 wheel, and resulted in smooth and continuous rotation. The upper and lower chip detectors were oil-wetted, normal in appearance, and devoid of any metallic particles. The fuel nozzle was in position and safety wired. The fuel nozzle and fuel screen were visibly clean, and residual clean fuel was found in the nozzle and fuel pump.
The helicopter was equipped with the Hiller center-cockpit mounted pedestal which contained basic flight and engine instruments, as well as switches and annunciator lights. Below that were the circuit breaker panel and some additional switches and controls. The pedestal and most of the instruments and switches appeared undamaged. A non-Hiller radio/instrument rack was mounted atop the central pedestal, but was found separated and forward of the helicopter in the wreckage.
A "dry bag" (a weather-proof rubberized fabric bag) and a "Pelican case" (a weather-proof sturdy plastic suitcase) were found strapped near the aft end of each external cargo rack. All bags and cases were securely closed and undamaged, but they were covered with turbine fuel. No indications of any straps coming loose, either in flight or due to impact, were observed. No non-helicopter hardware or components, aside from the previously-cited metal clipboard/case, were recovered from anywhere except the main wreckage location.
Several sections of an aluminum clipboard/case were recovered early in the debris field. The location of the fragments, including one which bore one "Idaho Fish and Game," and several anti-poaching stickers, enabled association of this unit with the accident flight.
In its undamaged state, the unit consisted of three approximately 9-inch by 12-inch aluminum plates, which were attached by a common hinge along one of the short edges. The plates were hinged and formed at the edges so that two of them (bottom and middle) formed a case for paper storage. A steel spring-clip assembly affixed to the top edge of the middle plate to serve as a paper/sheet retainer, and enabled the middle plate to be used as a hard writing surface. The third (top) plate functioned as cover for the papers retained by the clip. The overall thickness of the unit when fully closed was about 3/4 inch. The aluminum plate thickness was about 0.040 inches.
All three plates of the clipboard exhibited creasing, tearing, and red paint transfer marks. The spring clip was deformed, and torn into two sections. All damage was consistent with the clipboard being struck by the tail rotor blades. In consideration of the clipboard's light weight and large surface area, the damage was not consistent with that expected if the clipboard simply exited the helicopter and fell to the ground.
An "Advil liquid-gels" bottle that contained four different medications was found in wreckage. The bottle and its contents could not be associated with any particular person on the helicopter.
An anti-nausea wearable elastic band ("Sea-Band") was found in an unopened plastic case that was found secured in the right-side external rack. The Sea-Band could not be definitively associated with any particular person on the helicopter.
A Canon Powershot A80 digital camera was found on scene. The memory chip was removed and sent to the NTSB Recorders Laboratory in Washington DC for download. The card contained 46 images, none of which were related to the accident flight. The card was returned to IDFG for return to its owner or their next of kin.
Data Plate Discrepancies
The helicopter was originally manufactured as a UH12-L4 model, where the "4" designates that it was a 4-seat version. Review of aircraft historical records from the NTSB and FAA indicated that the helicopter was involved in an accident in 1967, and was subsequently shipped to and registered in Canada. In 1975, the helicopter was purchased by the Soloy Company and returned to the United States, where it was again registered with the FAA. In 1980, the helicopter was converted to turbine power, and airworthiness and registration documents generally indicate that the helicopter was still the 4-seat version. In 1998, the helicopter was converted from a UH12L4 to a UH12E. However, the documentation was incomplete, since the number of seats was not included in the designation. FAA documentation subsequent to that variously designated the helicopter as both the 4-seat and 3-seat versions.
A total of three data plates were found on the accident helicopter. All were attached to the outboard face of the left cabin seat 'deck' (the base of the seat). According to the Hiller representative, data plates were installed in one of two locations, either on the forward face of the left seat deck, or on the outboard face of the left seat deck (as found in the accident aircraft). However, the as-found orientation of the Hiller data plate was unusual; the data plate was rotated 90 degrees counterclockwise, while Hiller always installed that item right side up. In addition, Hiller always attached data plates with rivets, whereas the accident data plates were attached with screws.
A Hiller Aircraft Company data plate specified the "Manufacturer's Model" as "UH-12L4." A second data plate specified a "Conversion Designation" as "Hiller UH12E" a "Converting Agency" as "Valley Helicopter Service, and was dated "2-15-98." The third data plate bore the stamped text "FAA-PMA S.C.A. P/N 560-1000 UH-12 E." Based on the available evidence, the Hiller data plate was not compatible with, or representative of, the accident helicopter airframe.
According to the Hiller Aircraft representative, the L model 4-seat cabin was distinctly different from the E model 3- or 4-seat version. Examination of the wreckage indicated that the accident helicopter firewall was the standard 3-seat version, and there was no evidence that it was modified from an L model or 4-seat version firewall. The representative noted that the conversion of a UH-12L4 to a UH-12E4 was permitted by Hiller type design, through accomplishment of Hiller Service Bulletin instructions. Hiller Service Bulletins also provided guidance to convert a UH-12E3 to a UH-12E4 by adding a new forward section to the fuselage, as well as other structural changes. However, no Hiller-approved guidance existed to convert a UH-12L4 to a UH-12E3. The timing and details of how that non-representative Hiller data plate became associated with and attached to the accident airframe could not be determined.
IDFG Aircraft and Pilot "Carding"
The aforementioned IDFG Clearwater "Procedures Summary" stated that all "helicopter services for census, transport, or capture in which a Department employee flies shall be contracted through the U. S. Department of Interior National Business Center, Aviation Management (AM)" and that all "helicopters and helicopter pilots utilized by the Department must be carded by AM to perform the flying requirement." The "carding" was an AM-internal, mission-type specific, certification/approval process of the aircraft and pilots, and once the aircraft or pilot was determined to comply with the requirements, a physical paper card was issued to the aircraft or pilot. IDFG procedures required that a pilot "shall, upon request, present" his/her card that "denotes approval for the planned use" of that pilot on that mission. The Procedures also stated that a "current Department of Interior aircraft data card (No. OAS-47 for general use or No. OAS-36 for special use) must be displayed in a conspicuous location in the aircraft."
The AMD authorization card that was found in the helicopter was issued on October 23, 2009. However, according to the AMD/NBC representative, that card was not valid, and should have been rescinded by the AMD Western Regional Office (WRO), and physically removed from the helicopter. When the card was first issued, the helicopter "appeared" to meet the criteria for two specific contracts. Aircraft are carded in accordance with the type of contract, and different contracts may require different equipment or configurations. An AMD inspection in April 2010 determined that the helicopter did not meet the criteria for one of those contracts, due to certain avionics specification discrepancies. The helicopter failed a June 2010 re-inspection, but it was then determined that subsequent "carding" would not be dependent on another physical inspection, provided the correction of the identified deficiencies were corrected. On August 20, 2010, eleven days before the accident, LEA contacted AMD in order to determine the status of the "carding," but that situation was not jointly addressed and closed by LEA and AMD prior to the accident.
Pilot and Biologist Flight Preparations
According to the LEA Operations Manager (OM), the two IDFG biologists arrived at the LEA facility at WT33 about 0800, and met with the OM and the pilot to discuss the mission. The briefing was conducted in accordance with the published IDFG procedural summary regarding low altitude survey flights, and lasted about 15 minutes. Topics of discussion included the particular geographic areas being surveyed, AFF procedures, the location of the fuel truck, and the storage location of the IDFG satellite telephones. The briefing also included seating arrangements, and it was decided that since the male biologist was the more experienced and also the primary observer, he would be seated on the left side of the helicopter. Since the single set of pilot controls could be installed at either the center or left seat, the pilot was then relegated to the center seat, and the female assigned to the right seat.
After the brief, the pilot, the biologists, and the Operations Manager walked to the helicopter. The OM stated that during the preflight inspection, the personnel expended some effort to ensure that the equipment in the external baskets was properly secured. The pilot instructed the biologists to place the items that they needed during the flight in the cabin, and told them that he would secure the external cargo. The external cargo was placed in the cargo baskets, secured with multiple bungee-type rubber straps by the pilot, and their security was verified by the OM.
The OM then assisted the biologists with properly situating and restraining themselves in the helicopter, and the pilot then briefed the biologists on a variety of topics, including include emergency items and their locations, door operation, radio communications, seatbelt operation, and helicopter entry and exit procedures. The OM did not report that he or anyone else cautioned the biologists about unsecured items departing the cabin.
Cabin Door Transparencies and Latch Mechanisms
According to the Hiller representative, instead of being equipped with the standard flat or slightly curved transparencies, each cabin door incorporated a clear "bubble" or highly dished transparency, with its concave side towards the cabin interior. The bubble transparencies were commercially available as post-delivery modification options, and their purpose was to provide observers with a more-nearly-vertical downward view from the helicopter. Additionally, the concavity served to increase the physical width of the cabin, and could also serve as a convenient, albeit unintended, temporary resting location for certain articles in the cabin.
In addition, the latch mechanisms that were used for normal hinged operation of the cabin doors had been modified with non-Hiller hardware, and they were not in accordance with any Hiller- or supplemental type certificate-approved modifications. The installed latches were operated by handle rotation. Examination of the installed latch mechanisms revealed that the handle appeared to be susceptible to inadvertent activation, which could occur either by being physically bumped by the person seated next to the door, or by the handle getting caught in/by that person's clothing sleeve, particularly if the clothing was loose fitting. The Hiller representative stated that, for those reasons, he considered that latch design to be unsafe.
Those installed door-latch mechanisms were different than the ones depicted in the passenger briefing cards that were recovered in the wreckage. According to the Hiller representative, the latches depicted in the briefing cards were the standard Hiller-provided hardware. The briefing card correctly depicted that the Hiller latches were operated by handle translation fore and aft. No briefing card which depicted the operation of the installed latches (which was rotational instead of translational) was found in the wreckage.
Portable GPS Unit Information
The Garmin GPSMap 396 portable GPS unit that was recovered from the wreckage was confirmed to belong to LEA. Examination of the unit by a specialist at the NTSB Recorder Laboratory revealed that the unit was operating during the flight. The stored track data for the accident flight was successfully recovered. Review of the raw recovered data indicated that the recorded time base was 3 hours ahead (later than) PDT. Based on multiple data sources, the GPS-recorded times were converted to PDT for the synopsis below.
The track data indicated that the helicopter departed WT33 about 0850:35, and the last recorded point was at 0929:24. After departure, the helicopter climbed steadily at an average rate of about 142 feet per minute (fpm). The average groundspeed for the first 20 minutes of the flight was approximately 75 mph, and the average groundspeed for the second half was about 90 mph. The maximum "GPS altitude" in the data was 5,616 feet, which occurred at 0924:43. At that time, the helicopter was about 6 miles west-northwest of the impact location. The next seven GPS data points indicated that the helicopter descended at rate of about 190 fpm, over a span of 3 minutes and 56 seconds. The final two data points, spanning another 45 seconds, depicted an increasing descent rate. The instantaneous descent rate for the last two points was calculated to be 1,803 fpm. The final GPS-recorded point was at a GPS altitude of 4,116 feet. The main wreckage location was at an elevation of about 1,253 feet msl.
Accident Eyewitness Information
A total of 11 written witness statements were obtained. Nine of the witnesses observed the helicopter while it was airborne, and two only saw it subsequent to ground impact. In general, the witnesses' observations were relatively congruent. The majority observed items "falling" or "flying" off the helicopter, and three specifically cited tail rotor components. Most reported that the helicopter flew an increasingly steep descent, and that it was gyrating or rotating about one or more of its axes.
Two witnesses reported seeing geese flying near the helicopter, and one of them initially reported that a goose was struck by the main rotor. That witness subsequently recanted that testimony; he stated that the collision was an erroneous conclusion of his based upon the fact that the helicopter had crashed. Investigators sought but did not observe any evidence of a bird strike on the wreckage, and no bird carcasses or remains were observed in the debris field. One witness reported that the helicopter was in distress before she observed the components departing; she stated that the engine was "misfiring" above her home, which was located west of the impact site. The other eight flight witnesses either reported that the engine sounded normal, or that they did not notice any unusual engine sounds. One witness who observed the helicopter just prior to the impact stated that the right cabin door was open.
A gas station surveillance camera captured part of the helicopter's descent. The recording was sent to the NTSB Recorder Laboratory in Washington, DC. Review of the image data revealed that the helicopter's distance from the camera rendered it as a small dot, and a portion of the descent was obscured by the gas station structure. The helicopter appeared in the image for 3 seconds, was obscured for the next 2 seconds, and then reappeared for 1 second. No significant additional information was provided by the recording.