Mount Clemens, MI, USA
N103MH
Robinson R22 Alpha
The helicopter impacted terrain while attempting to land at a National Guard Base following a reported vibration in the helicopter. The pilot contacted air traffic control (ATC) stating he was 9 miles south of the base and requesting a clearance to transition through their airspace. The pilot was cleared through the airspace. When the helicopter was about 1 mile south of the base, the pilot reported to ATC that he was "... picking up a vibration." The controller asked the pilot to repeat the transmission and the pilot stated, "Yes sir the helicopter is starting to shake more violently sir." The controller informed the pilot that he could land at the base if he declared an emergency. Approximately 3 1/2 minutes later when the helicopter was 2 miles north of the base at 1,800 feet mean sea level (msl), the pilot reported that he was coming back to land. ATC cleared the pilot to land requesting if at all possible that the pilot land on the south side of the airport. The air traffic controllers viewed the helicopter through binoculars. They reported that they did not notice anything unusual with the helicopter and it appeared normal. One controller stated the helicopter crossed the northern end of the airport at 1,600 feet msl [1,020 above ground level (agl)]. Witnesses reported hearing the engine as the helicopter approached the airport. They stated that once the helicopter was approaching the south side of the airport, the nose pitched up then down. Witnesses described the descent angle as being between 45 and 70 degrees nose down. One controller estimated the descent began at an altitude of 1,400 to 1,500 feet msl [820 to 920 feet agl]. The helicopter impacted the grass leaving a wreckage trail approximately 299 feet long. Examination of the airframe, flight control systems, and engine did not reveal any failure/malfunction which would have resulted in the accident. A sound spectrum examination was performed on a re-recording of the ATC communications to document engine, rotor, or vibration sounds on the tape. This examination revealed that the rotor system background sounds were consistent with the main rotor rating at about 101% rpm. These sounds were consistent throughout the recording including the transmissions after the pilot reported a vibration. In addition, the tape was examined to determine if any airframe or rotor system vibrations could be identified. There were no additional sounds or vibrations identified during any of the transmissions.
HISTORY OF FLIGHT On July 28, 2004, at 1332 eastern daylight time, a Robinson R22 Alpha, N103MH, impacted terrain while attempting to land at the Selfridge Air National Guard Base (MTC), Mount Clemens, Michigan. The accident occurred on the airport between taxiways Bravo and Delta. The commercial pilot was fatally injured and the helicopter was destroyed. The 14 CFR Part 91 flight was operating in visual meteorological conditions without a flight plan. The last known departure point for the helicopter was from the Oakland County International Airport (PTK), Pontiac, Michigan, at 1245. The pilot of N103MH contacted the PTK air traffic control tower at 1245 requesting a departure to the east. The PTK tower controller issued departure instructions and cleared N103MH to depart as requested. The pilot of N103MH responded that he was departing as requested. The flight's destination is unknown. At 1310, the pilot of N103MH contacted the MTC control tower stating he was 9 miles to the south and he wanted to transition through their airspace via Metropolitan Beach. The tower controller approved the transition and issued an altimeter setting. At 1322, the pilot of N103MH informed MTC tower that he wanted to proceed direct to 57D, which is the airport identifier for the Ray Community Airport, Ray, Michigan. The tower controller approved this request and instructed the pilot of N103MH not to fly over the base. At 1323, the pilot of N103MH reported to the MTC tower "... I feel I'm picking up a vibration." The controller asked the pilot to repeat the transmission and the pilot stated, "Yes sir the helicopter is starting to shake more violently sir." At 1324, the MTC controller asked the pilot of N103MH if he was going to make it to 57D and the pilot responded that he did not know. The controller then told the pilot, "... if you declare an emergency and need to land here just let me know." At 1328, the pilot of N103MH transmitted, "Tower I gonna come back." The tower controller responded, "... verify you are declaring an emergency and landing at Selfridge." The pilot responded, "Yes sir it's going to be an emergency." The controller responded,"... roger wind at Selfridge estimated is three two zero at eight you're cleared at the approach end correction you are cleared to land if at all possible at the departure end of runway 19 that's at the south end of the airport at the intersection of 28." The pilot was asked to verify the number of people on board. At 1329, the controller transmitted, "Three mike hotel if at all possible on runway 28 ah just ah west runway one one nine that the perfect spot for you right there." One of the air traffic controllers who was in the tower at the time of the accident reported N103MH was about 1 mile southwest of airport when he informed the pilot that he could land at MTC if he had an emergency. He stated N103MH continued through their airspace and was about 2 miles northwest of the airport at 1,800 feet above mean sea level (msl), [1,220 feet above the ground (agl)], when the pilot stated he needed to land at MTC. The controller stated that he and the other controller on duty viewed N103MH with binoculars. The controller stated, "I noticed nothing unusual." The controller continued to state, "As he approached the base it looked as though he wasn't descending. As he crossed the northern end of the base I again looked at the radar and it indicated 1,600 feet msl [1,020 feet agl]. As he approached just south of midfield the helo made a sharp climb and slight turn to the left. It then nosed forward and did not recover. I estimate the fall was from about 1,400 feet to 1,500 feet msl [820 feet to 920 feet agl]." The other controller on duty in the tower stated, "We watched him from the tower go through from SE to NW avoiding the base proper. Didn't seem to be having problems controlling the helicopter. He got 3 NW of base and turned around to land here. Still didn't appear to have control problems. Came down between runway and parallel taxiway to land on south Bravo at intersection of 28/10. Got over Delta taxiway and what appeared to be a 45-60 degree angle down on whole helicopter. Crashed in that attitude approximately 200 yards south of Delta taxiway." Another witness who was located on the airport stated he first saw the helicopter traveling to the northwest as it flew past the airport. He then saw it as it was heading back to the southeast. This witness reported the helicopter was flying straight and level, the rotor blades were turning, and there was no smoke or fire coming from the helicopter. He stated he then saw the nose of the helicopter pitch up followed by a 70 degree nose down attitude. He stated the helicopter was about 200 to 300 feet above the ground when it nosed down. This witness reported "Before impact the pilot looked to be pulling up, but he impacted the ground." PERSONNEL INFORMATION Federal Aviation Administration records show the pilot held a commercial pilot certificate with a rotorcraft-helicopter rating with private pilot privileges for single-engine land. The pilot also held a flight instructor certificate with a rotorcraft-helicopter rating. The pilot held a second class medical certificate issued on February 13, 2004. This certificate contained the limitation "Holder shall wear corrective lenses while exercising privilege of airmen's certificate." The most recent pilot logbook located contained flight entries from 1997. The last flight entry was dated October 10, 1997. In the memoranda section of the logbook there was an entry showing that the pilot satisfactorily completed two flight reviews; one in a Robinson R22 on March 11, 2003, and the other in a R44, on July 7, 2003. On his application for his medical certificate dated February 13, 2004, the pilot reported having in excess of 6,000 hours of flight time. He reported that more than 200 hours of that time was accumulated in the last 6 months. The pilot was involved in another helicopter accident on July 20, 2003. With the assistance of a friend, the pilot completed a NTSB Form 6120.1/2 following the accident. On the form dated July 23, 2003, the pilot reported having 4,400 hours of flight time of which 4,030 hours were in helicopters. This accident involved a Robinson R22 Beta. The pilot reported having 3,500 hours of flight time in R22 helicopters. AIRCRAFT INFORMATION The helicopter was a single engine Robinson R22 Alpha, serial number 0454. The helicopter had two seats, a two-bladed metal main rotor, and skid type landing gear. The helicopter was powered by a 150 horsepower Lycoming O-320-B2C engine, serial number L-11708-39A. According to the aircraft and engine logbooks, a "100 hr annual inspection" was completed on July 10, 2004. The total aircraft time at this inspection was listed as 5,298.1 hours. The Hobbs time at the time of the accident was 5,315.0 hours. FAA records indicate the helicopter was purchased by the accident pilot on January 13, 1997. On August 24, 2001, the accident pilot sold N103MH to the current owner. The owner stated that he and the accident pilot were friends and that the accident pilot often borrowed N103MH. The owner stated that he usually stored the helicopter at his residence in Rochester, Michigan, and that he was out of town when the accident occurred. He stated that he received a voice mail message from the pilot on July 26, stating that he was taking N103MH back to the owner's house. The owner stated that the next day, the pilot told him that the weather had been bad so he did not return the helicopter to his house. The accident occurred the following day. METEOROLOGICAL INFORMATION A weather observation recorded at MTC at 1355 reported the following conditions: Wind variable at 6 knots; 10 statue miles visibility; few clouds at 10,000 feet above ground level (agl); temperature 27 degrees Celsius; dew point 14 degrees Celsius; altimeter 30.04 inches-of-mercury. At 1328, the air traffic controller at MTC issued the current winds to N103MH as being from 320 degrees at 8 knots. WRECKAGE AND IMPACT INFORMATION The helicopter impacted the open grass area on the southeast corner of the intersection of taxiways Delta and Bravo at MTC. The first impact was 242 feet south of taxiway Delta and 27.5 feet east of taxiway Bravo. The wreckage path was approximately 299 feet long. The path from the first impact to the main wreckage was on a magnetic heading of approximately 164 degrees. A global positioning system (GPS) receiver recorded the position of the main wreckage as 42 degrees 36.460 minutes north latitude, 82 degrees 50.419 minutes west longitude. The first piece of wreckage located near the initial impact point was the outboard 11 inches of one of the tail rotor blades. This was followed by a portion of the left forward skid strut, pieces of the left door panel, battery fragments, the transponder antenna, and pieces of the lower frame. Next along the wreckage path was an 8 foot 10 inch long ground scar that varied in depth from 5 to 7 inches. One end of this ground scar contained yellow paint transfers. The tips of the main rotor blades were painted yellow. This ground scar was followed by the outboard section of the other tail rotor blade, pieces of the left landing skid, the instrument panel, the right door, pieces of the cabin roof and the tail rotor gear box assembly. The tail boom and main rotor blades/mast assembly were located approximately 224 feet from the first impact point. The main wreckage was located about 57 feet from the tail boom and the engine was about 31 feet further down the wreckage path from the main cabin section. The main wreckage consisted primarily of the cockpit, transmission, and main rotor mast. Portions of the main wreckage were soot covered and had sustained fire damage. The fuel tank was ruptured and it was located approximately 40 feet from the main wreckage. The fuel cap was in place on the tank. The warning lights on the instrument panel were removed and examined under 10x magnification. None of the filaments appeared to be stretched. The master switch in the cockpit was off, the magnetos were selected to both, the carburetor heat was off, the engine primer was secured, the mixture control was extended about one quarter of an inch, and the fuel selector was in the ON position. The left landing skid was fractured at both the forward and aft strut attach points. The right skid was fractured at the aft strut attach point. The forward struts were separated from the cross tube on both the left and right sides. The rear cross tube was fractured approximately half way between its center and the left strut. Main rotor The lower sheave for the main rotor drive system remained attached to the engine. The clutch assembly remained attached to the transmission. Both V- belts were located at the accident site. Both were broken and showed no signs of curling or abnormal wear. The main rotor gear box turned freely by hand. Both main rotor blades remained attached to the main rotor hub. A portion of the main rotor shaft remained inside of the hub. Both pitch change links were separated at their respective upper rod ends. The lower rod end on one of the pitch change links was bent. The fork link between the swash plate and the main rotor yoke was separated at the rod end. All the fractured surfaces were uniform in appearance and no evidence of fatigue was noted. One of the main rotor blades was bent upward approximately 45 degrees beginning approximately 29-inches outboard of the blade root. The other blade was bent upward and then downward beginning approximately 36-inches from the blade root. Both blades contained compression buckling in numerous places. The swashplate assembly remained attached to the main rotor mast. The main rotor mast fairing sustained impact damage, but remained in place. All three collective push-pull tubes were intact from the mast to the jack shaft. All three of these push-pull tubes were bent and fractured below the jack shaft near their lower attach points. A 6-7 inch portion of the right A121-7 push-pull tube was not located. Engine The gascolator bowl and carburetor were separated from the engine. The carburetor bowl was located separate from the carburetor. The carburetor float was not located in the bowl. The exhaust manifold was separated from the engine and crushed. The oil cooler was pushed into the engine. The oil pan was separated from the engine. The number one cylinder exhaust valve rod was bent against the spark plug preventing removal of the plug. The end of the rod was bent against the valve rocker arm. The number two, three, and four cylinder top spark plugs were removed as was the bottom spark plug on the number one cylinder which was broken. The plugs that were removed were clean of deposits and light grey in color. The engine was rotated by hand and continuity was verified through the engine to the accessory housing. Thumb compression was verified on cylinders two, three, and four. The number one cylinder had sustained impact damage and it was cracked near the top spark plug. Air could be felt coming throught he crack when the engine was rotated. The right magneto was separated from the engine and the left magneto remained attached. The left magneto was removed and both magnetos were spun using a drill. Both magnetos produced spark on all of their leads. The scroll for the fan wheel had rotational scoring on the inside. The aft face of the alternator fan contained rotational scoring and rotational gear teeth marks. Tail boom Both tail rotor push-pull tubes were separated at their rod ends where the tubes connect to the pedal assembly in the cockpit. The upper tube was separated again approximately 10 inches aft of the pedal assembly. The lower rod was separated just forward of the lower bellcrank rod end. The push-pull tube to the aft bellcrank assembly was fractured at the rod end which remained attached to the bellcrank. The tail cone separated from the main wreckage at the first skin splice aft of the clutch assembly. The tail rotor drive shaft separated from the clutch assembly at the flex plate. The forward flex plate yoke remained attached to the clutch assembly. The attachment bolts were still in place on the ears of the flex plate and the ears were both bend aft in excess of 90 degrees. The flex plate and aft yoke remained attached to the drive shaft. Both ears on the aft yoke were bent, one forward and one aft. The tail rotor drive shaft was bent about 40 degrees between the forward flex coupling and the damper assembly. The slide bearing on the tail rotor output shaft was free to move, but movement was restricted by the bend in the shaft. The aft flex plate remained attached to the yoke at the gear box coupling. One of the attachment bolts pulled through the flange clearance hole on the drive shaft. All three stabilizers remained attached to the tail cone. The lower third of the horizontal stabilizer was buckled. The upper two-thirds of the upper vertical stabilizer were bent inward approximately 60-degrees toward the tail cone and the upper third sustained fire damage. The lower three-quarters of the lower vertical stabilizer were bent outward from the tail cone. Tail Rotor The tail rotor separated from the tail boom at the 90 degree gear box output gear. The gear teeth were intact. Smeared teeth marks from the gear were present around half of the opening where the gear fits into the gear box. The tail rotor pitch change links were intact. Both inboard sections of the tail rotor blades remained attached to the output shaft assembly. The outboard sections of both blades were separated and found along the wreckage path. The balance washers were in place on both tail rotor blade tips and both tips had dirt impacted in them. The tail Rotor Chip detector was clean of debris. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy on the pilot was conducted by the Macomb County Medical Examiner's Office on July 29, 2004. A Forensic Toxicology Fatal Accident Report
A loss of control in flight for undetermined reasons.
Source: NTSB Aviation Accident Database
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