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On February 22, 2006 about 1135 mountain standard time, a skid-equipped Robinson R22 helicopter, N7512G, was destroyed during an uncontrolled descent and subsequent collision with desert terrain, about 8 miles north of Scottsdale, Arizona. The helicopter was being operated as a visual flight rules (VFR) local area instructional flight under Title 14, CFR Part 91, when the accident occurred. The certificated flight instructor, seated in the left seat, and the passenger, seated in the right seat, sustained fatal injuries. All Out Aerial of Scottsdale operated the accident helicopter. Visual meteorological conditions prevailed, and company flight following procedures were in effect. The flight originated at the Scottsdale Airport, Scottsdale, about 1129.
During an on scene conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on February 23, the operator's president reported that the accident flight was an introductory flight instruction lesson for a prospective student. She said that a friend of the passenger had previously purchased a gift certificate for the 45-minute introductory flight.
According to the Scottsdale air traffic control tower (ATCT) specialist on duty at the time of the accident, the accident helicopter flew northbound after departure from the Scottsdale Airport. About 5 minutes after departure, the specialist received a brief mayday call, which he thought was from the accident helicopter. No further radio communications were received from the accident helicopter.
A witness located north of the Scottsdale Airport, about 1 mile south of the accident site, reported to the NTSB IIC that he saw the accident helicopter fly over him while he was working outside. He estimated that the helicopter was about 1,000 feet above the ground as it passed over him. He reported that helicopter traffic to the north of the Scottsdale Airport is a very common occurrence, and he is accustomed to hearing and seeing the same type of helicopter that was involved in the accident. He said that when the helicopter flew over him, the engine sounded normal. As the helicopter continued northbound, he heard what he thought was a "pop." He said the helicopter then started a shallow, controlled turn to the left, followed by two or three more popping sounds. He said that the helicopter then began to descend rapidly, and eventually started spinning counter-clockwise. As the helicopter's descent rate increased, the main rotor blades slowed, and the helicopter entered a near vertical descent. The witness noted that as the helicopter descended vertically, the main rotor blades had stopped turning, and appeared to be bent upwards, and were in a trail position. The witness said he could not hear any engine sounds during the helicopter's descent, and watched it until it descended behind a row of houses.
The pilot held commercial helicopter and helicopter flight instructor certificates, and a helicopter instrument rating. His most recent second-class medical certificate was issued on February 8, 2006, and contained no limitations or waivers. On his application for a medical certificate, dated February 8, he indicated that his total aeronautical experience consisted of about 1,200 hours, of which 150 were accrued in the previous 6 months.
According to the pilot's personal logbook that was provided to the NTSB IIC by family members, the pilot's total aeronautical experience consisted of about 1,191.3 helicopter flight hours. The last entry in the logbook was dated February 16, 2006.
The president of All Out Aerial stated the accident pilot was a part-time/contract helicopter flight instructor for the company, and that the accident occurred while the pilot was off-duty from his full time employer, Petroleum Helicopters, Inc., based in Lafayette, Louisiana.
Training / Employment background
A review of the accident pilot's Federal Aviation Administration (FAA) historical records on file in the Airman and Medical Records Center in Oklahoma City, Oklahoma, revealed that on January 7, 2004, the accident pilot obtained a student pilot certificate, and soon enrolled full time in a local helicopter flight school in Scottsdale. The flight school also operates additional helicopter flight training facilities in Long Beach, California, and Provo, Utah.
On February 4, 2004, the accident pilot failed his initial private helicopter certificate check ride. The flight school's president and designated pilot examiner (DPE) performed the check ride. According to the FAA records, the accident pilot then obtained an additional 9.8 hours of helicopter flight instruction, and subsequently passed a second check ride with the same DPE on February 10, 2004.
According to the president of the flight school, the accident pilot continued his enrollment at the flight school, working to obtain a commercial helicopter certificate, a helicopter instrument rating, a helicopter flight instructor certificate (CFI), and a helicopter flight instructor certificate for instruments (CFII). However, the president reported that the accident pilot's overall performance was poor, and that he had a series of failed phase checks, which slowed his advancement. He noted that the accident pilot struggled academically, requiring an exceptional amount of ground instruction, and still displayed an overall knowledge shortfall.
On May 29, 2004, the accident pilot successfully completed a check ride for a commercial helicopter certificate, as well as a helicopter instrument rating. The two check rides were conducted concurrently, and were performed at the flight school's Long Beach location. The flight school's DPE assigned to that location performed the check rides.
On September 25, 2004, the accident pilot failed his initial CFI check ride. The check ride was conducted at the flight school's Long Beach training facility. The flight school's DPE assigned to that location performed the check ride. According to FAA records, the accident pilot obtained an additional 2.0 hours of helicopter flight instruction, and passed a second check ride with the same DPE on September 27, 2004.
During an interview with the NTSB IIC on February 24, the president of the flight school reported that after the accident pilot obtained his commercial helicopter certificate, helicopter instrument rating, and certified flight instructor's (CFI) certificate, he continued working towards obtaining a certified flight instructor-instrument (CFII) certificate.
The flight school's president reported that historically, students that successfully complete the CFI and CFII programs are offered employment with the flight school as helicopter flight instructors. He said that the accident pilot expressed an open interest in working for the flight school once he obtained the required certificates, and he continued to work towards completion of a CFII certificate. The flight school president said that after reviewing the pilot's past performance, and while closely monitoring his recent progress, he, along with other senior flight school management personnel, collectively decided not to offer the pilot a position. Additionally, the group elected to discontinue any further flight-training activities with the accident pilot citing serious safety issues and concerns. In an interoffice memo dated October 4, 2004, the president summarized comments about the accident pilot that were provided by flight school personnel. The memo states, in part: "Over confident. Thinks he is much better than he is. RED FLAG. Gets overloaded and freezes. Unable to recover from overload. Dangerous in this situation because he isn't able to collect himself and figure out what to do next. Lack of reality about own performance." In an undated, hand written notation in the upper right hand corner of the memo, it states: "Post CFI check ride, 9/27 and retest on 9/28, was not recommended for CFII check ride - Unable to meet PTS [practical training standards] - consistently."
The flight school's president said he, along with a group of senior flight school managers, met with the accident pilot and informed him of their decision. The accident pilot then left the flight school, without completing his CFII certificate.
Previous Work Experience
On October 26, 2004, the accident pilot was hired as a helicopter flight instructor for a large helicopter flight instruction school, with multiple locations in Arizona, and other states. The flight school operated a large fleet of Robinson R22 and R44 helicopters, which were used for primary helicopter flight instruction. During a telephone interview with the NTSB IIC on March 8, 2006, the manager and chief flight instructor for the flight school's Mesa, Arizona, facility reported that the accident pilot worked for his school until his termination on July 7, 2005. He said that while the accident pilot was employed with the flight school, he accumulated about 800 hours of flight time while flight instructing in Robinson R22 and R44 helicopters. The manager stated that he was forced to terminate the accident pilot's employment due to a series of unheeded warnings concerning safety related standards, as well as his overall lack of performance. In a memo from the accident pilot's employment records dated July 7, 2005, the same day the accident pilot was terminated, the manager wrote, in part: "[The pilot] had a hard landing this morning. Said that it was the student's fault. Said that student got low rotor on go around from autorotation, and he did not catch it in time. They did a run on [landing] at 70 knots, went sideways, and ended up in the dirt. Very close call."
On July 25, 2005, the accident pilot applied for a job as a flight instructor with an operator of Robinson R22 and R44 helicopters located in Augusta, Kansas. During a telephone conversation with the NTSB IIC on November 30, 2006, the operator's president and owner reported that his preemployment interview for any prospective flight instructor includes an in depth oral interview, a written aptitude test, and flight examinations in both a Robinson R22 and R44 helicopters. The operator's president and owner flew with the accident pilot in an R44 helicopter, and had the flight school's DPE fly with him in an R22 helicopter. Each flight lasted about 1 hour. The operator's president and owner reported that the accident pilot performed well below acceptable standards, in all three categories, and the pilot was not offered a position.
On August 11, 2005, the accident pilot traveled to Sevierville, Tennessee to interview with a helicopter tour operator that operated Robinson R44 helicopters. During a telephone conversation with the operator's operations manager on November 29, 2006, he stated that the accident pilot attended a 3-day interview session that included 17.7 hours of flight time in a Robinson R44 helicopter. The operations manager reported that at the conclusion of the interview, the pilot was not hired.
On August 18, 2005, All Out Aerial hired the accident pilot as a primary helicopter flight instructor in a Robinson R22 helicopter, and to conduct local area flightseeing tours in a Robinson R44 helicopter, under Part 91 flight operations. The president of All Out Aerial reported that the accident pilot was hired as a contract pilot, and was scheduled for flights on an as needed basis. The president said that she had not flown with the accident pilot before he was hired, nor was she required to under Title 14, CFR Part 91 flight operations. She said that prior to hiring the accident pilot, she relied on a verbal recommendation from another flight instructor in the area concerning the accident pilot.
On October 3, 2005, the accident pilot interviewed with a large offshore helicopter operator based in Lake Charles, Louisiana, which subsequently hired the accident pilot. According to the operator, he completed his initial Part 135 ground school training course on October 13. He then began his initial flight training in an American Eurocopter EC-120 helicopter on October 22. According to the operator's chief pilot, the accident pilot accumulated about 10 hours of dual instruction in an EC-120 helicopter, but was unable to achieve the minimum standards required to pass a Part 135 check ride. The accident pilot was released from the operator's employment on November 18, 2005, and he returned to Scottsdale, and continued to occasionally fly for All Out Aerial.
According to the pilot's logbook, another large offshore helicopter operator, Petroleum Helicopters, Inc. hired him, and he began flight training in Bell 206 series helicopters on December 4, 2005. After completing his initial ground and flight training, he satisfactorily completed his initial 14 CFR Part 135 check ride on January 7, 2006. At the completion of his training and check ride, he had accumulated about 17.0 hours of flight time. He was then assigned as a pilot of Bell 206 series helicopters, operating offshore, in the Gulf of Mexico.
The helicopter was a Robinson R22 Beta II, equipped with a Lycoming O-360-J2A engine.
The helicopter and engine had accumulated a total time of 563.8 flight hours. The most recent annual /100 hour inspection of the engine and airframe was accomplished on January 3, 2006, 18.4 flight hours before the accident.
On August 23, 2005, 97.0 flight hours before the accident, a certificated airframe and power plant mechanic replaced both engine magnetos with two that had been recently inspected in accordance with a required 500-hour inspection. The mechanic made a notation in the engine logbook concerning his work on the helicopter's engine, stating, in part: "Engine not producing power, removed and replaced spark plugs with new ones. Adjusted mixture screw 1 1/2 turns out. Replaced mags with ones inspected IAW [in accordance with] 500-hour inspection." According to the operator, as well as other pilots that had recently flown the accident helicopter, there were no outstanding mechanical discrepancies or anomalies.
The closest official weather observation station is located at the Scottsdale Airport, which is 8 miles south of the accident site. On February 22, 2006, at 1053, an automated weather observation system was reporting, in part: Wind, 210 degrees at 2 knots; visibility, 10 statute miles; clouds and ceilings, clear; temperature, 55 degrees F; dew point, 19 degrees F; altimeter, 30.09 inHg.
WRECKAGE AND IMPACT INFORMATION
The National Transportation Safety Board IIC, along with representatives from Robinson Helicopter, Textron Lycoming, and inspectors from the Federal Aviation Administration (FAA) Scottsdale Flight Standards District Office, traveled to the accident site on February 23, 2006.
The helicopter crashed in a residential area and came to rest between two houses. There were no injuries to personnel on the ground, and there was no damage to the homes.
All of the helicopters major components were found at the accident site.
The helicopter's fuselage was found in an upright position, with the nose of the helicopter orientated on a 210-degree magnetic heading. Both of the helicopter's skid tubes were crushed and broken, and the helicopter's fuselage was lying atop the dry, hard packed desert soil.
The underside portion of the helicopter's engine sustained extensive impact damage. The carburetor assembly was shattered, and the mechanical linkages that link the cockpit controls to the carburetor were destroyed. Both of the engine's magnetos were torn from the mounting plates. The engine's ignition system wiring harness was cut through in numerous locations.
The cockpit/cabin compartment area was extensively crushed upward. The cabin compartment floor area, forward of the front landing gear cross tube assembly, was displaced in an inward direction. The front windshield bow, dividing the left and right sides of the forward windshield, was separated at its upper attach point with the cabin. The windshield Plexiglas was broken out of the frame, and only small portions of the windshield were present at the wreckage point of rest. The forward cabin doorposts were both buckled about mid-height in a forward and outward direction. The left and right doors were broken at their respective lower attach points. Both door latch mechanisms were in the latched position, but not retained in the airframe latch points. The outer portions of the cabin, below the left and right doorsills, were crushed and distorted in an upward direction. Overall, the main cabin area measured about 3-feet high.
Both of the helicopter's fuel tanks were ruptured along the lower portions of each tank. Each tank displayed evidence of significant downward liquid (fuel) hydraulic bulging. According to responding fire department personnel, there was a strong smell of fuel upon their arrival at the accident scene.
The main rotor mast assembly was displaced slightly forward, and the forward edge of the mast fairing was crushed adjacent to the upper cabin roof.
The tail boom assembly was severed about 12-inches aft of the tail boom attach points, and came to rest in an upright position, adjacent to the main wreckage. The tail rotor push-pull tube and tail rotor drive shaft assembly remained attached.
The main rotor blades remained attached to the main rotor hub and mast assembly.
Both of the main rotor blades were extensively damaged due to bending and over flexing, with extensive wrinkling on the top surface. One rotor blade displayed a small, upward indentation on the underside of the blade at the blade tip. No scratching or gouging of the paint was evident at the dent.
The main drive belts from the engine to the main transmission sheeve were intact. The belt tensioner was extended about 1 1/2 inches. Both the upper and lower sheeve assemblies had considerable impact damage consistent with a lack of rotation at impact.
To the extent allowed by impact damage, hand rotation of the main rotor blades in the direction of normal rotation established drive train continuity to the tail rotor output shaft. Hand movement of the blades opposite of normal rotation resulted in a locking of the freewheeling unit.
The engine fuel valve was found in the "on" position. The cockpit-mounted mixture control was found in the "full rich" position. The cockpit-mounted carburetor heat control was found in the "off" and unlocked position. The collective-mounted throttle arm was found in the full open position.
The engine fuel gascolator was ruptured, but contained a small amount of contaminate free, residual fuel. The internal gascolator screen was free of contaminants.
The bottom seat support structures for both seats were crushed downward. The aft, vertical bulkhead of the cabin was bulged slightly in a forward direction between the left and right seats.
Visual examination of the annunciator light bulb filaments revealed that all of the filaments were unbroken and tightly coiled.
Due to the impact damage and distortion of the airframe, the flight controls could not be moved by their respective control mechanisms. Fractures of the flight control push-pull tubes displayed 45 degrees fracture surfaces and flight control continuity was established throughout the airframe.
There were no preaccident mechanical anomalies discovered during the on scene review of the wreckage.
On February 23, 2006, the helicopter's wreckage was removed, under the direction of the NTSB IIC, from the accident site and transported to an aircraft salvage facility located in Phoenix, Arizona.
MEDICAL AND PATHOLOGICAL INFORMATION
A postmortem examination of the pilot was conducted under the authority of the Maricopa County Medical Examiner, 701 West Jefferson Street, Phoenix, on February 25, 2006. The cause of death for the pilot was attributed to multiple blunt impact injuries.
A toxicological examination was conducted by the FAA's Civil Aeromedical Institute (CAMI) on March 21, 2006, and was negative for drugs or alcohol.
TESTS AND RESEARCH
On February 23 and 24, 2006, an engine tear down and inspection was conducted under the direction of the NTSB IIC, at Air Transport, Inc., Phoenix. Also present at the engine tear down and inspection were aviation safety inspectors from the FAA's Scottsdale Flight Standards District Office, and representatives from Robinson Helicopter and Textron Lycoming.
A preliminary engine inspection revealed that the engine sustained extensive impact damage to the underside of the engine. The engine's carburetor, air induction system, and the magneto to spark plug wiring harness were destroyed. Both of the engine's magnetos were broken free from their respective mounting flanges. Both magnetos produced spark when the engine to magneto coupling was rotated by hand.
The external and internal engine examination revealed no mechanical anomalies.
On February 28, at the request of the NTSB IIC, an FAA inspector from the Scottsdale Flight Standards District Office conducted a functional bench test of the damaged magnetos. The inspector reported that after being installed on a magneto test bench stand, the left magneto operated with no anomalies detected, and the magneto produced bright blue spark, continuously. He said that after the right magneto was installed on the magneto test bench stand and power was applied to the impulse coupling, the magneto failed to produce spark at a low rpm. He added that when the rpm was increased, only one cylinder lead would produce spark.
The FAA inspector reported that once the irregularity was discovered with the right magneto, he discontinued any additional testing activities, and the magnetos were not dissembled. Both magnetos were shipped to the NTSB IIC for further testing and evaluation within a laboratory environment.
On April 19, 2006, an air safety investigator assigned to the NTSB's Northwest Regional Office conducted an inspection and comprehensive test run of both magnetos. The inspection and test run procedure was accomplished at the analytical laboratories of Teledyne Continental Motors (TCM), located in Mobile, Alabama. The investigator reported that after being installed on a magneto test bench stand, both magnetos operated in accordance with the manufacture's specifications, and produced bright blue spark, continuously. The NTSB investigator noted that he conducted numerous test runs of both magnetos, over a two-day period, with no anomalies observed. At the conclusion of the bench testing procedure, both magnetos were disassembled and inspected, and no preaccident mechanical anomalies were revealed. A copy of the investigator's written report is included in the public docket for this accident.
NTSB Sound Spectrum Analysis
A copy of the digital audio tape (DAT) from the accident helicopter's air to ground radio communications was forwarded to the NTSB vehicle recorder laboratory in Washington, DC. A Safety Board senior electronics engineer examined the four separate recorded radio transmissions contained on the tape, and identified them as originating from the accident helicopter. The electronics engineer, using a computer based audio spectrum analyzer, analyzed the recorded radio transmissions.
The first, second, and third recorded radio transmissions were conversations between the pilot and the Scottsdale ATCT specialist on duty prior to, and after departure from the Scottsdale Airport. The electronics engineer reported cockpit sounds consistent with the main rotor system operating at approximately 101% rpm. No warning horns or tones could be identified in any of the three recorded radio transmissions.
The last recorded radio transmission took place about 5 minutes after departure, with the pilot stating: "Mayday, Mayday." The electronics engineer reported cockpit sound signatures consistent with the main rotor system rotating at approximately 93% rpm. He noted that no warning horns or tones could be identified in the pilot's fourth and final recorded radio transmission.
The Safety Board electronics engineer noted that the audio spectrum analyzer program is unable to quantify engine sounds as it relates to engine rpm. A complete copy of the Safety Board's sound spectrum study factual report is included in the public docket for this accident.
An air safety investigator with Robinson Helicopter reported that the main rotor system is normally operated between 101% and 104% rpm. He said that when the rotor rpm drops below 97%, the low rotor rpm warning horn sounds, in conjunction with the illumination of a yellow warning light on the annunciator panel, which immediately warns the pilot of a low rotor condition. He added that when the collective is lowered to its full down position while in-flight, with the main rotor rpm operating below 97%, a collective micro-switch is activated, which subsequently silences the low rotor warning horn and light system.
Low Rotor Sensing System
On March 14, 2007, the accident helicopter's low rotor sensing system and low rotor warning horn system, were functionally tested under the direction of NTSB's Regional Director of the Southwest Regional Office, Gardena, California. The functional test was conducted at Robinson Helicopter Company's corporate headquarters in Torrance, California. According to the regional director's written inspection report, the low rotor sensing unit and low rotor warning horn system operated in accordance with the manufacturing specifications. The regional director noted that the only component of this system that was not tested, due to impact damage, was the collective micro-switch. A copy of the regional director's written inspection report is included in the public docket for this accident.
A Scottsdale Police Department detective that responded to the accident scene and photo documented the accident site, reported to the NTSB IIC that the keyed ignition/magneto switch was found in the right magneto position upon his arrival.
Published Emergency Procedures
The FAA approved Robinson Helicopter Company flight manual, in the emergency procedures section, Power Failure-General, states, in part: "...An engine failure may be indicated by a change in noise level, nose left yaw, oil pressure light or decreasing engine rpm..."
Pilot's Required Emergency Action is:
1. Lower collective immediately to maintain rotor rpm, and enter normal autorotation.
2. Establish a steady glide at approximately 65 knots.
3. Adjust collective to keep rotor rpm in the green arc, or, full down if lightweight prevents attaining
97% rotor rpm.
4. Select landing spot and if altitude permits, maneuver so landing into wind.
A Robinson Helicopter Company published safety notice, SN-10, dated October 1982, and revised in June 1994, addresses the dangers of a low rotor rpm conditions in Robinson Helicopters. The safety notice states, in part: "A primary cause of fatal accidents in light helicopters is the [pilots] failure to maintain rotor rpm. To avoid this, every pilot must have his reflexes conditioned so he will instantly add throttle and lower the collective to maintain rpm in any emergency." Additionally, the safety notice states, in part: "If the pilot not only fails to lower the collective, but instead pulls up on the collective to keep the ship [helicopter] from going down, the rotor will stall almost immediately. When it stalls, the blades will either "blow back" and cut off the tail cone or it will just stop flying, allowing the helicopter to fall at an extreme rate. In either case, the resulting crash is likely to be fatal. No matter what causes the low rotor rpm, the pilot must first roll on the throttle and lower the collective simultaneously to recover rpm BEFORE investigating the problem. It must be a conditioned reflex. In forward flight, applying aft cyclic to bleed off airspeed will also help recover lost [rotor] rpm."
A complete copy of the Robinson Helicopter Company safety notice, SN-10, is included in the public docket for this accident.
The Safety Board released the wreckage to the owner's representatives on February 24, 2006. The magnetos that were originally retained by the FAA's Scottsdale Flight Standards District Office, and subsequently shipped to the Safety Board for examination, were released to the owner's representatives on August 2, 2006.