Aviation Accident Summaries

Aviation Accident Summary LAX05FA189

Lucerne Valley, CA, USA

Aircraft #1

N7015Q

Robinson R44

Analysis

The helicopter impacted level terrain and rolled onto its left side while maneuvering during a low-level photo flight. The pilot was flying southbound along a racecourse on a photo flight when he made a hard 180-degree turn, and lost control of the helicopter. As the helicopter began a spin to the right, the pilot noted a loss of rpm and altitude. He asked the certified flight instructor (CFI)/safety pilot to take the flight controls. As the CFI took control of the helicopter, he realized that the rpm's were decaying and that the helicopter was too low to recover the rpm. He attempted to cushion the impact with the collective. Both pilots reported that there were no preimpact mechanical anomalies with the airframe or engine. No evidence of any preimpact mechanical malfunction was found during the post accident investigation that would have precluded normal operation. During the accident flight, the helicopter was running approximately 131 pounds over the maximum gross weight for an Out of Ground Effect hover for the existing atmospheric conditions. The helicopter was being operated in a high density altitude environment, which was computed to be 7,350 feet mean sea level. The pilot received his rotorcraft helicopter rating 7 days prior to the accident. He had approximately 77 hours of total rotorcraft flight time at the time of the accident. The helicopter manufacturer indicated that photo flights were a high risk phase of flight and issued a safety notice SN-34. Safety Notice SN-34 recommended at least 500 hours and extensive training in both low rpm and settling-with-power recovery techniques prior to flying photo shoot type flights.

Factual Information

HISTORY OF FLIGHT On May 28, 2005, about 1150 Pacific daylight time, a Robinson R44, N7015Q, impacted terrain while maneuvering during low-level flight near Lucerne Valley, California. Concrete Paving Contractors, Inc., was operating the helicopter under the provisions of 14 CFR Part 91. The owner, a private pilot, a certified flight instructor (CFI) safety pilot, and one passenger were seriously injured; the helicopter was destroyed following a post impact fire. The local personal flight departed Redlands, California, at 0951. Visual meteorological conditions prevailed, and no flight plan had been filed. The approximate global positioning system (GPS) coordinates of the primary wreckage were 34 degrees 37.46 minutes north latitude and 116 degrees 41.02 minutes west longitude. Witnesses observed the helicopter in the area, flying low during a desert off road race. The helicopter crossed the racecourse on a southbound heading. Witness reported that shortly after crossing the racecourse it appeared that the helicopter was attempting to reverse course back towards the north. The helicopter pitched nose down and leveled off just before it impacted into a dry streambed. Upon impact, the helicopter burst into flames. All three people on board the helicopter sustained burns while exiting the burning helicopter. The operator submitted a Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) on June 21, 2005. The pilot submitted a revised NTSB Form 6120.1/2 on August 11, 2005. The pilot stated that the helicopter and engine had no mechanical failures or malfunctions during the flight. The National Transportation Safety Board IIC interviewed the pilot on August 4, 2005. The pilot stated that he was flying southbound along the racecourse. He made a hard right 180-degree turn, and lost control of the helicopter. The CFI took over the controls and tried to recover the helicopter. The helicopter hit the ground and rolled onto its left side. With regard to preflight planning, the pilot indicated he went over the "numbers" with the CFI, but he could not remember what they were, only that they were okay. The pilot indicated that he used to fly the off road races in his airplane. The accident flight was his second flight utilizing a helicopter for overflying off road races. The accident flight was the first time the pilot had flown this type of operation with his own helicopter, and as pilot-in-command. The pilot had just completed the Robinson Helicopter Company (RHC) safety course, but he stated he did not know about the RHC safety notice SN-34, which cautions inexperienced helicopter pilots about flying photo flights. The accident pilot requested a copy of the NTSB Form 6120.1/2 that his company had submitted on his behalf to review and correct any mistakes that may have been included in the original. The IIC interviewed the CFI on June 15, 2005. The CFI reported that he was the safety pilot for the flight and not pilot-in-command, and that they had been flying for about 1 hour on the photo flight when the accident occurred. They were southbound and crossed the racecourse. The private pilot started to turn the helicopter to the right when the helicopter started to spin to the right. The private pilot told the CFI that he had lost control and asked the CFI for help. The CFI took over the flight, got onto controls, and tried to keep the helicopter in a level attitude. The helicopter was descending, and the CFI realized the rotor rpm (revolutions per minute) was decaying. He knew he was too low to try to recover the rpm, so he tried to cushion the impact with the collective. The helicopter impacted the ground and rolled onto its left side, with the main rotor blades striking the ground. He did not recall hearing the low rotor horn until the helicopter was on the ground. After the accident sequence, the pilot, the CFI and the passenger exited the burning helicopter. Prior to the accident, the CFI thought the helicopter had been operating normally. The CFI estimated that the pilot had about 70 hours of helicopter flight time. Prior to the flight, they talked about helicopter performance and weight and balance issues. PERSONNEL INFORMATION Private Pilot/Owner A review of Federal Aviation Administration (FAA) airman records revealed that the pilot held a private pilot certificate with ratings for airplane single engine land and multiengine land. An additional rating for rotorcraft helicopter was added on May 21, 2005. The private pilot held a third-class medical certificate issued on April 29, 2004. It had no limitations or waivers. The Safety Board IIC obtained the following aeronautical experience from a review of the FAA airmen medical records on file in the Airman and Medical Records Center located in Oklahoma City, Oklahoma. On the pilot's most recent Airman Certificate and/or Rating Application, dated May 21, 2005, he reported a total airplane time of 1,550 hours and a total helicopter time of 50 hours. The owners company, Concrete Paving Contractors, Inc., via its director of sales, submitted a Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), dated June 20, 2005. In that report, the company reported that the pilot had a total of 77 flight hours in the accident make and model. The Safety Board IIC reviewed a copy of the pilot's logbook, that was obtained from the pilot's flight school, which listed a total flight time of 77.4 hours in the accident make and model as of May 20, 2005. On August 11, 2006, the pilot submitted to the Safety Board IIC a revised Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), in which he reported he had a total of 160 hours in the accident make and model. The pilot also submitted a copy of his logbook information to his insurance company in which various entries were different from the copies of the logbooks that the Safety Board IIC had previously received. The differences were as follows: May 14, 2005, logbook entry, the flight time was 8.6 hours in the flight school logbook copy and now read 18.6 hours. May 16, 2005, logbook entry, the flight time was 4.1 hours in the flight school copy and now read 14.1 hours. May 17, 2005, logbook entry, the flight time was 3.5 hours in the flight school copy and now read 13.5 hours. The Safety Board IIC interviewed the CFI that had flown with the accident pilot from May 14th through May 17th. The CFI provided to the Safety Board IIC copies of his logbook. The accident pilot did fly with him from Redlands to Florida. The flight was approximately 27.7 hours, not 50 hours as recorded in the accident pilot's logbook he provided to the insurance company. Certified Flight Instructor (CFI)/Safety Pilot The CFI held a commercial pilot certificate with a rating for rotorcraft-helicopter and a certified flight instructor rating for rotorcraft-helicopter. The CFI held a second-class medical certificate issued on March 26, 2005, with no limitations or waivers. According to the CFI, he had 520 hours total flight time in rotorcraft, including 130 hours of flight instruction given in rotorcraft. The CFI had received his endorsement for the R44 on May 21, 2005. AIRCRAFT INFORMATION The helicopter was a Robinson Helicopter Company R44, serial number 0462. A review of the helicopter's logbooks revealed that the helicopter had a total airframe time of 496 hours at the last annual inspection on December 6, 2004. The engine was a Textron Lycoming, serial number L-25243-40A. Total time recorded on the engine at the last annual inspection was 496 hours on December 6, 2004. The Safety Board IIC examined records indicating that the owner/pilot had purchased the accident helicopter in March 2005. Examination of the maintenance records revealed no unresolved maintenance discrepancies against the helicopter prior to departure. The weights of the two pilots were obtained from the pilots' FAA records. The passenger weight was obtained from California Department of motor vehicle records. The manufacturer's representative calculated the gross weight of the helicopter based on the following weights: Empty weight: 1,442 pounds Pilot (right seat): 230 pounds CFI (left seat): 180 pounds Rear seat passenger: 175 pounds Main fuel tank: 117.6 pounds Auxiliary fuel tank: 60 pounds The calculated takeoff gross weight was 2,335.4 pounds with a center of gravity (CG) of 94.76 inches. The calculated gross weight at the time of the accident was 2,219.6 pounds with a CG of 94.27 inches. METEOROLOGICAL INFORMATION The accident site was located at 4,266 feet mean sea level (msl). The temperature was about 90 degrees Fahrenheit. The barometric pressure for the area was 29.85 inHg. The density altitude was computed at 7,350 feet msl. The closest official weather observation station was Barstow-Daggett Airport, Daggett, California (KDAG), which was located 17 nautical miles (nm) northwest of the accident site. The elevation of the weather observation station was 1,927 feet msl. An aviation routine weather report (METAR) for KDAG was issued at 11:54. It stated: winds 360 degrees at 4 knots; visibility 10 statute miles; skies clear; temperature 91 degrees Fahrenheit; dew point 40 degrees Fahrenheit; altimeter 29.82 inHg. WRECKAGE AND IMPACT INFORMATION The Safety Board IIC and the FAA accident coordinator examined the wreckage at the accident scene. The first identified point of contact (FIPC) was a ground scar adjacent to the main wreckage. The debris path was along a magnetic heading of 340 degrees. The orientation of the fuselage was along a magnetic heading of 100 degrees. The main wreckage was contained within 50 feet of the FIPC. The post impact fire completely consumed the cabin area of the helicopter. TESTS AND RESEARCH The Safety Board IIC, the FAA accident coordinator, Robinson Helicopter Company, and Textron Lycoming, parties to the investigation, examined the wreckage at Aircraft Recovery Services, Littlerock, California, on June 1, 2005. The main skids of the helicopter separated upon impact. The helicopter suffered extensive thermal damage due to fire. The cockpit area was almost completely destroyed by fire. The collective was in the full up position based on the remains of the A333-1 collective friction slider stop. The mixture control guard was found loose in the wreckage. The anti-torque pedals were in a neutral position. The main rotor gearbox was completely destroyed by fire. All that remained of the gearbox and main rotor mast tube area were the gears, bearings, and main rotor shaft. The main rotor shaft appeared to be straight. The droop stops and droop stop "tusks" appeared to be undamaged. The elastomeric teeter stops were not located, but the retaining brackets appeared undamaged. Investigators noted no deformation to the main rotor mast beneath the elastomeric stops. The main rotor hub exhibited slight circular arc scoring and melted material transfer immediately inboard of the root fitting on one side. Both main rotor blades exhibited trailing edge compression buckling, severe distortion and some fire damage. The intermediate flex coupling was intact, but distorted. Recovery personnel cut the tail rotor drive shaft to facilitate recovery of the helicopter. The tail rotor drive shaft damper bearing assembly remained intact. The bearing rotated freely, and the linkage appeared to function normally. The aft flex coupling did not appear to be damaged. The tail rotor gearbox contained blue oil and rotated freely. The tail rotor pitch change slider bearing rotated freely. The tail rotor output shaft and hub were intact and appeared to be straight. The tail rotor blades were intact; one appeared to be straight, the other was bent slightly inboard. The engine remained attached to the airframe by the engine mount. The engine sustained moderate thermal damage; predominate at the accessory area of the engine. The post impact ground fire had mostly consumed the fiberglass cooling shroud. Investigators removed the bottom spark plugs. All spark plug electrodes were mechanically undamaged. The spark plugs' electrode coloring corresponded to normal operation according to the Champion Aviation Check-A-Plug AV-27 Chart. Oil residue was noted on spark plug Nos. 1, 3, and 5, consistent with the engine position at the accident site and recovery. A borescope inspection revealed no mechanical deformation on the valves, cylinder walls, or internal cylinder heads. Investigators manually rotated the crankshaft utilizing the engine-cooling fan. The crankshaft rotated freely, and the valves moved approximately the same amount of lift in firing order. Investigators obtained thumb compression on all cylinders in firing order. Clean, uncontaminated oil was observed in all six-rocker box areas. The magnetos were secure at their respective mounting pads, but were destroyed by the post impact fire. The carburetor remained securely attached to its mounting flange. It sustained moderate thermal damage. The throttle and mixture controls were securely attached to their respective control arms of the carburetor. All engine compartment fuel lines were in place and secure. The fuel valve was found in the ON position. Investigators disassembled the carburetor, and noted that the carburetor bowl was free of contaminates. The float assembly remained secure at its attachment, and free of damage. The heat valve at the carburetor airbox was situated at the hot "ON" position. The engine manufacturer's representative found no evidence of preimpact catastrophic mechanical malfunction or fire. RESEARCH Robinson Helicopter Company issued Safety Notice SN-34 in March 1999, titled "Photo Flights - Very High Risk." Safety Notice SN-34 describes the problems encountered when the pilot slows the helicopter below 30 KIAS (indicated airspeed) and then attempts to maneuver the helicopter. "The helicopter can rapidly lose transitional lift and begin to settle. An inexperienced pilot may raise the collective to stop the descent. This can reduce rpm thereby reducing power available and causing even greater descent rate and further loss of rpm. Because tail rotor thrust is proportional to the square of rpm, if the rpm drops below 80 percent nearly 1/2 of the tail rotor thrust is lost and the helicopter will rotate nose over. Suddenly the decreasing rpm also causes the main rotor to stall and the helicopter falls rapidly while continuing to rotate." Safety Notice SN-34 recommends that photo flights only be conducted by well trained, experienced pilots who (1) have at least 500 hours pilot-in-command in helicopters with over 100 hours in the model flown; (2) have extensive training in both low rpm and settling-with-power recovery techniques; and (3) are willing to say no to the photographer and only fly the aircraft at speeds, altitudes, and wind angles that are safe and allow good escape routes. Safety Notice SN-34 refers to Safety Notice SN-24, with regard to low rpm rotor stalls. An analysis of hover performance capability was prepared by Robinson Helicopter Company based on an FAA approved formula for the R44. The analysis assumes an altitude of 4,266 feet msl with an outside air temperature of 90 degrees Fahrenheit. The aircraft can hover In Ground Effect at a gross weight of up to 2,364 pounds. The aircraft can hover Out of Ground Effect at a gross weight of up to 2,089 pounds. Per the estimate in the accident report, the accident aircraft weighed 2,220 pounds; 131 pounds negative for these conditions when hovering in Out of Ground Effect. ADDITIONAL INFORMATION The IIC released the wreckage to the owner's representative on March 14, 2006.

Probable Cause and Findings

the pilot's failure to maintain adequate main rotor rpm and directional control while maneuvering at low altitude. Contributing factors in the accident were the helicopter's gross weight in excess of the maximum hover out of ground effect limit, a high density altitude, and the pilot's lack of overall experience with regard to low rpm and settling-with-power recovery techniques.

 

Source: NTSB Aviation Accident Database

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