Meadview, AZ, USA
N1783U
Cessna T207A
The airplane impacted mountainous terrain in an extreme nose-down attitude following a departure from controlled flight. The purpose of the flight was to check the weather conditions for passenger tour flights that day. The pilot reported about 20 minutes prior to the accident that the ceiling was 6,500 feet mean sea level (msl). Radar data showed that following this weather report, the airplane's radar track continued eastbound and upon its return westbound, at an altitude of about 6,000 feet msl, the airplane entered a series of altitude fluctuations approximately 1 mile west of a ridge that was the location of the accident, descending at 4,000 feet per minute while turning northbound, and then climbing at 3,900 feet per minute while traveling eastbound, prior to disappearing from the radar. The airplane impacted on the eastern side of the ridge. There were no monitored distress calls from the aircraft and no known witnesses to the accident. Prior to the accident, there were reports of vibrations during flight on this aircraft, although many went unreported to maintenance personnel. The day (and flight) prior to the accident, a pilot experienced a vibration during flight with passengers and it was not reported to maintenance personnel because it was logged improperly in the operator's maintenance tracking system. No corrective actions were taken. During the post accident examinations, no portions of the right elevator and trim tab were identified in the wreckage, or at the accident site. The bracket attachment to the right elevator was found loose within the wreckage and was torsionally twisted counterclockwise (aft). Ground and aerial searches for the missing parts based on a trajectory study were unsuccessful. This aircraft was equipped with a foam cored elevator trim tab that was installed during aircraft manufacture. A service difficulty report (SDR) query showed that 47 reports had been issued on elevator trim tab corrosion and many included reports of vibrations during flight. On January 20, 2005, the Federal Aviation Administration (FAA) issued Special Airworthiness Information Bulletin (SAIB) CE-05-27, which addressed potential problems with foam-filled elevator trim tabs in the accident make/model airplane, and Cessna 206 and 210 series airplanes. The SAIB indicated that the foam-filled elevator trim tabs, manufactured until 1985, were reported to have corrosion between the tab and the foam. The SAIB further said, in part, "When the skin of the trim tab becomes thin enough due to the corrosion, the actuator can pull the fasteners through the skin and disconnect. When this occurs, the tab can flutter." Some reports indicated prior instances of "vibrations in the tail section and portions of the elevator tearing away with the trim tab." Prior to the issuance of the SAIB, Cessna Aircraft Company issued a Service Bulletin (SB) SEB85-7 on April 5, 1985, that addressed elevator and trim tab inspection due to corrosion from moisture trapped in the foam cored trim tabs. Based on a review of the airplane's logbooks, the SB was not complied with, nor was the operator required to do so based on the FAA approved maintenance specifications.
1.1 HISTORY OF FLIGHT On December 8, 2004, about 1031 mountain standard time (MST), a Cessna T207A, N1783U, collided with mountainous terrain 27 nautical miles southwest of Meadview, Arizona. The commercial pilot, the sole occupant, sustained fatal injuries; the airplane was destroyed. King Airelines, Inc., was operating the airplane under the provisions of 14 CFR Part 91, as a weather scouting flight. A combination of visual and instrument meteorological conditions prevailed along the general route of flight, and no flight plan was filed. The airplane departed Henderson Executive Airport, Las Vegas, Nevada, at 0903 Pacific standard time (PST) (1003 MST). According to the operator, the pilot was on a weather scouting mission to determine the current weather conditions in tour areas that did not have weather reporting capabilities. The normal tour routes are to fly to Wilson's Ridge (approximately 25 nm east of Henderson Airport), over Temple Bar, Arizona (approximately 15 miles east of Wilson's Ridge), and then to Grand Canyon West, Peach Springs, Arizona (an additional 25 nm east of Temple Bar). During the weather scouting flight, the pilot would normally fly east along these areas until an accurate depiction of the weather could be determined. The projected flight time was 1 hour. According to personnel at Silver State Helicopter's fixed base operator (FBO) at Boulder City Municipal Airport, Boulder City, Nevada, a pilot identifying himself as King 2, called on the radio about 1010 MST. He asked if the radio operator could call King Airelines and let them know that their 0930 PST flight could be launched and that the ceiling was 6,500 feet mean sea level (msl). The radio operator called King Airelines and relayed the message. Approximately 2 minutes later, King 2 asked if the message had been relayed and the radio operator advised him that she had relayed the message. The radio operator told the National Transportation Safety Board investigator that radio coverage in the area is limited, so that on occasion, King Airelines pilots would radio Silver State and have them transmit messages back to Henderson via telephone. 1.1.2 Search and Rescue Activities The accident flight was due to arrive at Henderson by 1000. Company policy states that if the flight is 30 minutes past the arrival time, the pilot must notify the Chief Pilot or the Director of Operations via radio communications. When the pilot did not report back to Henderson by 1030, the Director of Operations began contacting local airports. The Director of Operations then contacted the Park Service and asked them to dispatch ground personnel to conduct a search of the local airports. Around 1130, the Director of Operations attempted to call the local Federal Aviation Administration (FAA) Flight Standards District Office (FSDO) unsuccessfully. The Director then called the Reno Flight Service Station, who in turn contacted the Air Force Rescue Coordination Center (AFRCC), Langley, Virginia. AFRCC issued an Alert Notice (ALNOT) at 1333 MST. Clark County Search and Rescue personnel discovered the aircraft wreckage at 1530 MST the day of the accident. 1.1.3 Radar Information Investigators reviewed radar data at the Nellis Air Traffic Control Center, Nellis Air Force Base, Las Vegas, using the Micro En route Automated Radar Tracking System (EARTS). According to Nellis personnel, during the accident flight, air traffic control did not assign the airplane a discrete transponder squawk code. A review of recorded radar was undertaken to identify the accident airplane's flight track. Only one track was observed that was consistent with the accident airplane's projected route of flight, and subsequent disappearance over the accident site area. The observed radar track and Mode C (altitude encoding) report was first observed near the Henderson Executive Airport, as the target proceeded in a southeasterly direction. The target continued in a southeast-east direction while climbing to 5,600 feet msl and maintaining groundspeeds between 130 and 160 knots. Between 1020 and 1025 MST, the target climbed to 7,500 feet msl while turning to the south. The target then made a series of turns while maintaining altitudes between 6,000 and 7,500 feet msl and groundspeeds between 110 and 140 knots. During the last 4 minutes of the recorded radar data, the target descended to approximately 6,000 feet msl and traveled west. After the target had passed over Wilson's Ridge, about 1031 MST, the target made a series of extreme altitude fluctuations while on the west side of the ridge, and then dropped off radar. 1.2 PERSONNEL INFORMATION 1.2.1 Pilot Information King Airelines, Inc., hired the pilot on April 6, 2004. A review of the operators' personnel records for the pilot revealed that he held a commercial pilot certificate with single and multiengine airplane and instrument airplane ratings. The pilot also held a flight instructor certificate for single and multiengine airplanes and instrument airplane. He held a first-class medical certificate issued on October 18, 2004. The pilot began his flight training at the University of North Dakota, Grand Forks, North Dakota, in 2000. He obtained a private pilot certificate on May 22, 2001. The pilot completed the remainder of his training at Westwind School of Aeronautics, located at Phoenix Deer Valley Airport, Phoenix, Arizona, over a period of about 2 years. From March 2003 until March 2004, the pilot was employed as a flight instructor at Westwind School of Aeronautics. In addition, from March 2003 until October 2003, the pilot was employed by a local FBO at the Deer Valley Airport. King Airelines pilots described the accident pilot as someone that flew by the rules and was not a risk taker. In addition, he was said to be well-respected among the line pilots and offered guidance and support to new-hire pilots. 1.2.2 72-Hour History The pilot's roommate reported that nothing appeared abnormal with the pilot on the days leading up to the accident. He kept a normal sleep schedule, was not taking any medications, and did not report any illnesses. The roommate further stated that the pilot generally enjoyed his job at King Airelines, but had career aspirations to fly as an air tanker pilot for the United States Forest Service. 1.2.3 Recent Experience The pilot tracked his flight time using an electronic logbook and copies of the logbook were obtained from the pilot's family. The last entry was dated November 26, 2004. The electronic logbook combined experience in the Cessna 206 and 207, and showed a total of 101.3 hours flight time in those make and model airplanes. The pilot logged 106 hours of simulated instrument flight time, and 49.5 hours of ground simulator time. The pilot reported 4.5 hours of actual instrument time. The pilot's total flight time was 1,209.2 hours. On October 29 though October 31, the pilot rented a Beech 76 with another King Airelines pilot and flew 9.1 flight hours using instrument flight plans. During these flights, the pilot logged 3.1 hours of simulated instrument flight time and 2 instrument approaches. According to the Chief Pilot at King Airelines, the pilot was a model employee and pilot, and held approximately 700 hours of total flight time when hired. He was a conservative pilot and primarily flew the multiengine airplanes. The pilot had recently submitted a scheduling proposal that would have allowed the line pilots to have more time off-call while still working the same number of hours. 1.3 AIRCRAFT INFORMATION 1.3.1 General Aircraft History The single engine airplane was a Cessna T207A, manufactured in 1977, serial number (SN) 20700383. A review of maintenance records indicated that an FAA Approved Airworthiness Inspection Program (AAIP) inspection number 1 was completed on November 16, 2004, at a total airframe time of 12,583.2 hours, and a tachometer time of 1,951.8 hours. The inspection included both external and internal inspections of the airplane and its components, and operational performance checks of the engine. The airplane was operated by King Airelines since 1990 as an air tour airplane. Prior to that time, it was owned by another tour operator in the Las Vegas area. The Teledyne Continental Motors (TCM) engine TSIO-520-M, SN 513532, underwent a remanufacture at Western Skyways, Inc., Montrose, Colorado, on October 9, 2000. At the time of the remanufacture, the engine had accumulated 3,200 hours. The McCauley Propeller, SN 816513, was three-bladed. At the time of the last AAIP inspection, the propeller had accumulated 928.4 hours since its last overhaul. The airplane was manufactured with a foam-filled trim tab and right and left elevator trailing edges. The foam was used to form rigidity within the structures. 1.3.2 Fueling According to a company flight plan, the airplane departed Henderson with 50 gallons of fuel onboard. 1.3.3 Aircraft Installed Equipment The minimum equipment list for the airplane showed that the airplane was equipped with a vertical speed indicator, transponder with altitude encoding capability, VHF omni-directional receiver (VOR), instrument landing system (ILS) with glide slope and localizer receiver, marker beacon, altimeter adjustable to barometric pressure, airspeed indicator, gyroscopic pitch and bank indicator, gyroscopic directional indicator system, distance measuring equipment (DME), and a magnetic compass. King Airelines did not require all of the above mentioned instruments for passenger operations; however, they were all functional prior to the pilot's departure from Henderson. The airplane was not equipped with electric trim. 1.3.4 King Airelines Maintenance Forms and Aircraft Discrepancy History According to the FAA accepted General Operations Manual for King Airelines, all pilot discovered mechanical irregularities were to be entered on King Airelines Form 10, "Pilot Reported Discrepancy Log." This included irregularities discovered during pre and post flight inspections, as well as during a flight. At the time of the accident, it was King Airelines policy to keep the form onboard the airplane for a period of 90 days, prior to it being filed. Mechanical irregularities discovered during maintenance activities were to be entered by maintenance personnel on King Airelines, Form 11, "Inspection Discrepancy Log." King Airelines also used a post flight inspection report, which was not intended for maintenance squawks but solely for pilots to log post flight inspection information. On King Airelines, Inc., AAIP Pilot Reported Discrepancy Log (Form 10), an entry dated June 27, 2004, stated the following: "RH elevator/stab damaged underside near counterweight" On June 28, 2004, a notation in the corrective action section stated the following: "Fabricated and installed repair patch on rt [right] horizontal stab and rt [right] elevator" The aviation maintenance technician (AMT) that performed the repair submitted a written statement to the National Transportation Safety Board investigator-in-charge (IIC) on December 14, 2004, to the best of his recollection of the corrective action taken on June 28. A pilot had requested that the AMT look at the right horizontal stabilizer following the first flight of the day due to a scratch on its upper surface. According to the AMT, there was a dent in the top skin of the stabilizer and a scratch going outward toward the elevator balance weight. Initially, they thought that possibly a rock had impacted the structure, but based on the angle of the scratch away from the dent, it appeared to them that something else had happened. The AMT asked the pilot if he drove under something and the pilot replied no. The AMT expressed that the extent of the damage was viewed more as cosmetic rather than structural. The AMT believed that the repair consisted of a small repair patch over the dent on the right horizontal stabilizer and touchup of the scratched paint. He also thought that another AMT verified his work. On King Airelines, Inc., AAIP Inspection Discrepancy Log (Form 11) an entry dated November 14, 2004, stated the following: "Reported engine vibration at cruise." On November 16, 2004, a notation in the corrective action section states the following: "Noted 200 rpm drop. Repaired power ignition lead number 2 cylinder. Ground run check good." Three company pilots that had flown the airplane reported feeling a noticeable vibration during flight. The pilots thought that the vibration was due to the propeller or the engine and did not write up the airplane. Several weeks prior to the accident, a company pilot experienced a vibration during flight in the accident airplane. He reported the discrepancy to maintenance personnel, and completed the Form 10. According to the pilot, the Director of Maintenance test flew the airplane and did not experience any vibration. The airplane was returned to service. The record of this discrepancy, and the corrective actions taken, was onboard the airplane and destroyed during the accident sequence. The Director of Maintenance and the owner of King Airelines submitted a joint written statement describing the work that was performed following the maintenance squawk. They recalled that the Form 10 read, "Engine running rough, Aircraft [seems] to vibrate." The corrective action was as follows, "Ground run with the mixture and fuel flow check. The engine was running lean and fuel flow was on the high side. Teledyne Continental Motors Service Bulletin 97-3 was referenced for fuel pressure and fuel flow settings. The engine fuel system was adjusted to the published parameters. A test flight was conducted and logged as satisfactory. Aircraft was returned to service." Two days prior to the accident, the company pilot that had reported the previous vibration experienced a vibration during a tour flight with a load of passengers. At an elevation of 6,500 feet msl, 27 inches manifold pressure, and 2300 rpm, he felt a vibration. He looked outside of the airplane to determine if the vibration was coming from outside. Because he had already written up the airplane for a vibration, he logged the vibration in the post flight inspection report and it was not reviewed by maintenance personnel prior to the accident flight. 1.3.5 FAA Special Airworthiness Information Bulletin & Cessna Service Bulletins 1.3.5 FAA Special Airworthiness Information Bulletin & Cessna Service Bulletin On January 20, 2005, the FAA issued Special Airworthiness Information Bulletin (SAIB) CE-05-27. The issuance of the SAIB was not as a result of the accident investigation. The SAIB addressed potential problems with foam-filled elevator trim tabs in the accident make/model airplane, and Cessna 206 and 210 series airplanes. The SAIB indicated that the foam-filled elevator trim tabs, manufactured until 1985, were reported to have corrosion between the tab and the foam. The SAIB further said, in part, "When the skin of the trim tab becomes thin enough due to the corrosion, the actuator can pull the fasteners through the skin and disconnect. When this occurs, the tab can flutter." Reports indicated "vibrations in the tail section and portions of the elevator tearing away with the trim tab." Prior to the issuance of the SAIB, Cessna Aircraft Company issued a Service Bulletin (SB) SEB85-7 on April 5, 1985, that addressed elevator and trim tab inspection. It noted, "evidence of internal skin to foam separation, soft spots, paint blisters, unsealed edges of exposed foam, foam deterioration or corrosion are cause for replacement of the assembly." Based on a review of the airplane's logbooks, the SB was not complied with, nor was the operator required to do so based on the FAA approved maintenance specifications. 1.3.6 Service Difficulty Reports In a maintenance Service Difficulty Report (SDR) (97ZZZX3709) obtained from the FAA SDR database, an in-flight vibration in a Cessna U206 was reported. A search of the FAA's Service Difficulty Report (SDR) database revealed an in-flight vibration experienced in a Cessna U206 (SDR 97ZZZX3709). The SDR stated, in part, "…elevator v
a loss of control due to the in-flight separation of the right elevator and elevator trim tab control surfaces. The precipitating reason for the elevator separation could not be resolved as related to the tab foam core issue with the available evidence.
Source: NTSB Aviation Accident Database
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