CHI04FA197

A loss of control in flight for undetermined reasons.

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