N61NM

HISTORY OF FLIGHTOn August 25, 2017, about 1850 Pacific daylight time, a Robinson R-44 Raven II helicopter, N61NM, was substantially damaged when it encountered a dynamic rollover during a forced landing in Eldorado Hills, California. The commercial pilot and his passenger received minor injuries. The helicopter was registered to A M Helicopter Services, LLC and operated by a private individual as a personal flight, which was conducted under the provision of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the local flight that departed Auburn Municipal Airport (AUN), Auburn, CA at 1830.

According to the accident pilot and airframe and powerplant mechanic, he flew the helicopter once in the airport traffic pattern and then taxied to the fuel isle. After adding 20 gallons of 100 low lead (LL) aviation grade gasoline, the pilot and his passenger, also an aircraft mechanic, departed on the accident flight. The magnetos were checked for correct operation prior to departure, but the pilot did not recall if he allowed the rpm to stabilize before he captured the measurement. They flew around a soccer field, so the passenger could take photographs and then flew to a nearby lake where they completed a practice autorotation. During the end of the maneuver, as they approached the ground, both the pilot and passenger heard the low rotor rpm horn, which was accompanied by its corresponding annunciator light. Subsequently, the pilot increased the engine power, which in turn increased the rpm.

The pilot and passenger decided to meet a friend at his home, they changed course to the nearby destination and approached his property from the north. The pilot decelerated and transitioned into an in-ground effect hover over his friend's backyard and noticed that the downwash started to blow debris into the pool. Although his friend was signaling the pilot to land on a concrete block adjacent to the pool, the pilot elected to select an alternate landing site. He flew the helicopter backwards into and out of ground effect hover over a solar panel array, which was at a lower terrain elevation, but the main rotor rpm started to decay and the low rotor rpm horn engaged. The pilot applied full power, which increased the manifold pressure to 28 in Hg and placed the rotor rpm at approximately 96%; however, the helicopter started to descend. The pilot lowered the collective, which returned the rotor rpm to the normal range. He then completed a right pedal turn and rotated the helicopter about 360° to look for a more suitable landing site, but the helicopter started sinking again. The pilot informed his passenger that he was going to set the helicopter down on the solar panel array. As the left skid impacted a solar panel, the passenger exited the left side of the helicopter and ran to a grassy area east of their position. Almost simultaneously, the helicopter ascended about 20 ft prior to descending towards the grassy area. Subsequently, the right skid impacted the ground followed by the left, which resulted in a dynamic rollover and the helicopter came to rest on the left side.

According to the property owner, the passenger of the accident helicopter contacted him to ask if they could land on his property. About 4 minutes after the owner gave them permission to land, he heard the helicopter approaching his backyard from the north. During this time, he observed single puffs of smoke coming from the helicopter every 3-4 seconds. The property owner directed the helicopter to land on the pool deck, made up of a concrete slab, but there appeared to be some confusion as he then observed the helicopter enter a hover over some foliage behind his pool. The helicopter turned 90° to the east while sliding to the left while it discharged more smoke. After the helicopter ascended over the solar panels it entered a pedal turn as it started to descend. The helicopter then turned west and north before it disappeared from the witness' view. Approximately 15 seconds later the helicopter "popped" back up into the witness' view momentarily and turned southeast, now with a constant stream of smoke coming from the helicopter. The stream of smoke ceased for a second and then continued. The helicopter settled back down out of the witness' view over the solar array and seconds later he heard it impact branches and then the ground. He recounted that the smoke color was a very dark gray color that never changed, but the engine sounded continuous throughout the accident sequence.

In a subsequent interview, the passenger stated that he did not hear an engine or rotor harmonic during the dynamic rollover. The pilot and passenger did not observe any engine roughness.

A postaccident examination of the helicopter revealed substantial damage to main rotor blades and cockpit. PERSONNEL INFORMATIONAccording to the pilot, he had accumulated a total of 3,985 total flight hours and 66.5 hours in the helicopter make and model. The pilot estimated that he flew about 3 total hours in the helicopter make and model within the 90 days that preceded the accident. He further estimated that he amassed about 500 total flight hours in Robinson R-22s, but did not accrue any flight experience in the R-22 in the last 90 days. AIRCRAFT INFORMATIONAccording to FAA records, the helicopter was manufactured in 2006 and registered to A M Helicopter Services on May 20, 2008. The helicopter was powered by a Lycoming IO-540-AE1A5, a direct drive, air cooled, 260 hp engine. A review of the logbooks revealed that the helicopter's most recent 100 hour airframe inspection was completed on May 21, 2017 at an accumulated time of 1,991.3 flight hours. At the time of the accident, the helicopter had accumulated a total of 2,095 flight hours.

The engine's most recent 100-hour inspection was performed by IA Maintenance, a service facility in Woods Cross, Utah. In this entry, the mechanic recorded that he performed a differential compression check, cleaned, gapped, and tested the spark plugs, inspected the magneto and tachometer points and checked engine to magneto timing. Additionally, the mechanic noted that he complied with Lycoming Service Bulletin 301B. With the exception of the hobbs times, the previous 100-hour inspection record, dated January 1, 2017, was identical to the May 2017 entry including the cylinder compression values. The helicopter owner reported that a top overhaul had never been completed.

The owner leased the accident helicopter to Utah Helicopters, a flight school, for 2 years beginning in 2015 for flight instruction to generate income before the tail and main rotor blades reached their maximum calendar life limit. According to a representative of the flight school, they accumulated about 500 hours of flight time in the accident helicopter. It was subsequently returned to the owner on August 21, 2017 at which time the pilot reported to the owner that the helicopter was underpowered. According to the accident pilot, the ferry pilot's description of the helicopter's performance was not communicated to him when the owner invited him to fly the helicopter after it arrived.

The two pilots that ferried the accident helicopter from Utah to California had accumulated about 300 hours of flight time in the helicopter when it was operated by the flight school. Both pilots commented that the helicopter had been underpowered since the school received it, but the helicopter passed inspections, so they "managed" the performance deficiency. METEOROLOGICAL INFORMATIONThe recorded weather was captured from a weather station at AUN, located approximately 13.5 nm north of the accident site.

The 1855 recorded weather observation at AUN included wind from 250° magnetic, wind calm, visibility 10 statute miles, clear skies, temperature 32° C, dew point 26° C, and an altimeter setting of 29.86 inches of mercury. AIRPORT INFORMATIONAccording to FAA records, the helicopter was manufactured in 2006 and registered to A M Helicopter Services on May 20, 2008. The helicopter was powered by a Lycoming IO-540-AE1A5, a direct drive, air cooled, 260 hp engine. A review of the logbooks revealed that the helicopter's most recent 100 hour airframe inspection was completed on May 21, 2017 at an accumulated time of 1,991.3 flight hours. At the time of the accident, the helicopter had accumulated a total of 2,095 flight hours.

The engine's most recent 100-hour inspection was performed by IA Maintenance, a service facility in Woods Cross, Utah. In this entry, the mechanic recorded that he performed a differential compression check, cleaned, gapped, and tested the spark plugs, inspected the magneto and tachometer points and checked engine to magneto timing. Additionally, the mechanic noted that he complied with Lycoming Service Bulletin 301B. With the exception of the hobbs times, the previous 100-hour inspection record, dated January 1, 2017, was identical to the May 2017 entry including the cylinder compression values. The helicopter owner reported that a top overhaul had never been completed.

The owner leased the accident helicopter to Utah Helicopters, a flight school, for 2 years beginning in 2015 for flight instruction to generate income before the tail and main rotor blades reached their maximum calendar life limit. According to a representative of the flight school, they accumulated about 500 hours of flight time in the accident helicopter. It was subsequently returned to the owner on August 21, 2017 at which time the pilot reported to the owner that the helicopter was underpowered. According to the accident pilot, the ferry pilot's description of the helicopter's performance was not communicated to him when the owner invited him to fly the helicopter after it arrived.

The two pilots that ferried the accident helicopter from Utah to California had accumulated about 300 hours of flight time in the helicopter when it was operated by the fl...