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NTSB investigation record

LAX02FA173

Completed

Robinson R22 Beta· N7194J

Date
May 22, 2002
Location
Mammoth Lakes, CA
Conditions
VMC
Record
Published September 2, 2021

Primary finding

Probable cause

The pilot's poor decision to continue the flight into the rising mountainous terrain, and subsequent failure to maintain clearance with the trees. Contributing factors were rising mountainous terrain, the high density altitude, and the exceeded weight and balance and performance capability of the helicopter.

Investigator assessment

Analysis narrative

The helicopter impacted trees and the rising mountainous terrain approximately 7.8 miles from the airport. Prior to departure, the helicopter's main and auxiliary fuel tanks were topped off with fuel. Witnesses observed the pilot and passenger board the helicopter, and reported that the engine start was normal. The engine idled for two minutes, the rpm increased to "full power". The helicopter lifted off the ground "approximately 3 to 4 feet, and then set down very controlled." The engine rpm decreased for a few seconds, then back to "full power". The helicopter lifted off the ground, turned to the west, and moved about 30 feet to "the yellow X (a closed taxiway), and set down very hard." One witness stated that "[it] seemed like they had difficulty trying to get off the ground." After a few seconds, the helicopter lifted off again dragging the forward portion of the skids on the taxiway, departed to the west and "did not gain a lot of altitude." The maximum allowable gross weight of the helicopter was 1,370 lbs. Considering the occupants, miscellaneous baggage, and full of fuel, the helicopter's gross weight, at the time of departure, was 1,459.25 lbs. The density altitude at the departure airport and the accident site was calculated at 8,702 feet and 10,681 feet, respectively. According to the approved rotorcraft flight manual, the in-ground-effect (IGE) hover ceiling versus gross weight, and the out-of-ground-effect (OGE) hover ceiling versus gross weight performance limits were not available beyond 1,370 lbs. gross weight. The performance specifications had been approved up to the maximum allowable gross weight. The engine was test run on the airframe, and no anomalies or discrepancies were noted.

Source record

Factual narrative

HISTORY OF FLIGHT On May 22, 2002, at 1506 pacific daylight time, a Robinson R22 Beta single-engine helicopter, N7194J, was destroyed when it impacted trees and rising mountainous terrain during climb to cruise near Mammoth Lakes, California. The private pilot and his certified flight instructor (CFI) sustained fatal injuries. The helicopter was registered to and operated by the private pilot and another private individual. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The cross-country flight departed the Mammoth Yosemite Airport (MMH), Mammoth Lakes, approximately 1500, and was destined for the San Luis County Regional Airport (SBP), near San Luis Obispo, California. During a telephone interview conducted by the NTSB investigator-in-charge (IIC), an employee of the pilot reported the pilot and his passenger departed SBP approximately 0930, on the morning of the accident and flew to Mammoth Lakes on a pleasure flight. Employees of Hot Creek Aviation, a MMH fixed base operator (FBO), reported the helicopter arrived at MMH approximately 1350. The pilot and his passenger had lunch at the FBO, stated this was their first time flying into MMH, and requested the helicopter's fuel tanks be topped off with fuel. Line personnel fueled the helicopter with 20.0 gallons of 100LL aviation grade fuel. At 1445, the line personnel observed the private pilot enter the right side, and the passenger enter the left side of the helicopter. The witnesses reported the helicopter's engine start was "normal." The engine idled for approximately two minutes, then the engine rpm increased to "full power," the helicopter lifted off the ground "approximately 3 to 4 feet, and then set down very controlled." The engine rpm decreased for a few seconds, then was brought back to "full power." The helicopter lifted off the ground, turned to the west, and moved about 30 feet to "the yellow X [a closed taxiway], and set down very hard." One witness stated, "[it] seemed like they had difficulty trying to get off the ground." After a few seconds, the helicopter lifted off again, dragging the forward portion of the skids on the taxiway. The helicopter departed to the west, and "did not gain a lot of altitude." The witnesses observed the helicopter fly toward Mammoth Mountain until they lost sight of it behind the west hangars. A pilot-rated witness, who was located at his mountainside residence between the accident site and the airport, reported that at the time of the accident, the wind was gusting to 30 knots. Based on previous flight experience in the area of the accident site, the witness stated he often "encountered high turbulence and strong downdrafts" near the top of the mountain pass. At 1605, the Mammoth Lakes Police Department was notified that two hikers located the wreckage of a helicopter in an area near Lake Mary Road, approximately 7.8 nautical miles southwest of MMH, at an elevation of 8,750 feet mean sea level (msl). During a telephone interview conducted by the NTSB IIC, the co-owner of the helicopter stated that this was the pilot's first flight in the accident helicopter to MMH. The co-owner stated the pilot had the CFI accompany him for "high altitude" flying. PERSONNEL INFORMATION The pilot received a private pilot certificate with an airplane single-engine land rating on July 17, 1976, and an airplane multi-engine land rating was added on May 6, 1999. He received a private rotorcraft helicopter rating on April 7, 2001. The pilot was issued a second-class medical certificate on September 25, 2001, with the limitation "MUST POSSESS GLASSES WHICH CORRECT FOR NEAR VISION." According to the pilot's logbook, he had accumulated 203.3 flight hours in helicopters of which 201.4 flight hours were in the accident helicopter make and model. Of those 201.4 hours, 112.7 flight hours were accumulated in the accident helicopter. The last logbook entry was dated May 18, 2002. The flight instructor received a private pilot certificate with an airplane single-engine land rating on October 8, 1985, a private rotorcraft helicopter rating on March 25, 1987, and an airplane multi-engine land rating on October 25, 1987. He obtained a commercial rotorcraft helicopter rating on April 19, 1988, and a helicopter CFI rating on February 1, 1991. The pilot was issued a second class medical certificate on December 3, 2001, with no restrictions or limitations. According to the pilot's logbooks, as of May 19, 2002, he had accumulated a total of 5,973.8 flight hours of which 5,115.6 hours were accumulated in helicopters, 4,273.2 hours were accumulated in the accident helicopter make and model, and 3,516.2 flight hours were accumulated as a CFI. In addition, the pilot had logged 2.5 flight hours as "mountain flying." The pilot completed the Robinson Helicopter Company (RHC) Safety Course on June 12, 2001, and the pilot's logbooks indicated that the pilot had completed the RHC Safety Course on several previous occasions. The flight instructor was the owner of Heloman Helicopters, of San Luis Obispo. Heloman Helicopter's services included flight instruction, aerial photography, aircraft rental, and aircraft charters. AIRCRAFT INFORMATION The two-bladed, two seat, black and white Robinson helicopter, serial number 3198, was issued a standard airworthiness certificate on March 22, 2001, and was registered to the pilot and co-owner on December 19, 2001. The helicopter was powered by a 180-horsepower Lycoming O-360-J2A engine, de-rated to 131-horsepower (serial number L-37992-36A). The most recent annual inspection was completed on December 1, 2001, at which time, the airframe and engine had accumulated a total of 500.0 hours. On February 27, 2001, the altimeter, static system, and automatic altitude reporting system were tested to 16,000 feet msl. The helicopter was equipped with main and auxiliary fuel tanks. The main fuel tank total capacity was 19.8 gallons (19.2 gallons usable), and the auxiliary fuel tank total capacity was 10.9 gallons (10.5 gallons usable). The basic empty weight, and longitudinal and lateral centers of gravity (CG) for the helicopter, were calculated on March 7, 2001, and were found to be 873.85 pounds (lbs), 103.8 inches and -0.1 inches, respectively. The calculations were based on the actual weights and moment arms from the helicopter equipment list. According to the approved rotorcraft flight manual, the maximum allowable gross weight for the accident helicopter was 1,370 lbs, with a longitudinal CG range between the 96.5 inch forward limit and the 100.0 inch aft limit (measurements are referenced to the datum point, which located 100 inches forward of the rotor centerline). The lateral CG range was between the 2.20 inch left limit and the right limit of 2.60 inches (measurements are referenced to the centerline of the mast: - is left, + is right). Considering the occupants, miscellaneous baggage, and full of fuel, the helicopter's gross weight at the time of departure was 1,459.25 lbs with the calculated longitudinal CG at 97.56 inches, and the lateral CG at +0.06 inches. The following weights were used for the weight and balance calculation: pilot (right seat) - 218 lbs, flight instructor (left seat) - 180 lbs, miscellaneous baggage - 10 lbs, and fuel - 178.2 lbs (29.7 gallons total / 6 lbs per gallon). The weights of the occupants were obtained from their most recent pilot medical certificates, and the miscellaneous baggage was weighed at the salvage facility after the helicopter was recovered. According to the approved rotorcraft flight manual, the maximum operating DA for the accident helicopter was 14,000 feet msl. According to the approved rotorcraft flight manual section 5, "PERFORMANCE", the in-ground-effect (IGE) hover ceiling versus gross weight, and the out-of-ground-e

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