N225JM

HISTORY OF FLIGHTOn October 23, 2019, at 1553 mountain standard time, a Robinson R44 II Raven, N225JM, was substantially damaged when it was involved in an accident near Las Vegas, Nevada. The airline transport pilot and passenger were fatally injured. The helicopter was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight.

The pilot contacted the fixed based operator (FBO) that rented the helicopter in the early afternoon on the day of the accident and asked office personnel if the helicopter was available to rent later that afternoon. One of the schedulers responded that the helicopter was undergoing maintenance, and the pilot stated that he would stop by the office anyway to check if the maintenance was done and put money on his account. The pilot and passenger arrived about 10 minutes later. The pilot asked why the helicopter was in maintenance and the office personnel told him that an earlier flight was canceled because that pilot had found sediment in the fuel tanks. The accident pilot stated that he was happy to wait, and about 20 minutes later, the flight instructor who had canceled the earlier flight called, stating that the maintenance was done, and the helicopter was ready to fly. The pilot and passenger planned to take a 1-hour flight. (see figure 1.)

Figure 1: Airport to Accident Site

A witness, who was also a pilot, stated that while riding his motorcycle, he initially saw the helicopter in the upper right-corner of his vision at an estimated 100 to 200 feet above ground level (agl) in a nose-up attitude and in a very steep descent angle heading opposite his direction of travel. He estimated that the helicopter was moving about the same speed as the traffic (about 50 mph). He witnessed the helicopter impact the ravine adjacent to the road (about 200 ft ahead of him and 100 ft to the right) and break apart on impact.

A review of radar flight track data indicated that the helicopter departed and continued west-southwest toward the Red Rock Retention Basin checkpoint. After clearing the Class Bravo airspace, the returns showed a left 360° orbit over Blue Diamond Road, consistent with the pilot circling over a remote control (RC) airpark and the Desert Sportsman’s Rifle Club. Thereafter, the track was consistent with the pilot loosely following the road around Calico Basin and climbing up to 4,700 ft mean sea level (msl), about 400 ft agl. The helicopter then made a left turn and serval maneuvers over the Red Rock National Conservation Area washes, including a possible touchdown, during which the forward airspeed speed was reduced to 0 kts. After performing serval low-level maneuvers, the track was consistent with the helicopter following Blue Diamond Road toward the north-northeast. The last radar return was at 1553:23 about 1 nautical mile (nm) west-southwest of the accident site. The last 30 seconds of the track data indicated an airspeed of about 100 to 120 kts at an altitude between 500 to 700 ft agl. (see figure 2 below.)

Figure 2: Radar Track Data PERSONNEL INFORMATIONThe pilot held an airline transport pilot certificate with a rating for airplane multiengine land, and commercial privileges for airplane single-engine land and rotorcraft-helicopter. According to information compiled from Federal Aviation Administration (FAA) records, as of the date of the accident, he had approximately 15,000 total hours of flight experience.

The pilot’s rotorcraft logbook indicated that the pilot began flying helicopters in 2013 with a majority of his earlier experience acquired in a Schweizer helicopter. His last flight was recorded on March 3, 2019, during which he received a 0.9-hour checkout in an R44, including practice autorotations, low rotor rpm recovery, and settling with power. The flight included 6 daytime landings and occurred 234 days before the accident flight. The pilot’s total rotorcraft experience was 352.1 hours, of which 8 flights were in the R44 helicopter, totaling 12.3 hours. The logbook indicated that he had flown the accident helicopter once before on February 8, 2019, for 1.5 hours during which he flew from North Las Vegas to Henderson, Nevada, and back; there were no other recorded helicopter flights from North Las Vegas.

A logbook endorsement dated July 2016 stated that the pilot had completed the awareness training in accordance with paragraphs "(b)(2)(ii)(a-d) " of Section 2 of Special Federal Aviation Regulation (SFAR) No. 73. The currency requirements provided in the SFAR state that no person may act as pilot-in-command of an R44 helicopter carrying passengers unless the pilot in command has met the recency of flight experience requirements of §61.57 in an R44. In pertinent part, § 61.57 (a)(1) states that “Except as provided in paragraph (e) of this section, no person may act as a pilot in command of an aircraft carrying passengers … unless that person has made at least three takeoffs and three landings within the preceding 90 days and -(i) The person acted as the sole manipulator of the flight controls; and(ii) The required takeoffs and landings were performed in an aircraft of the same category, class, and type (if a type rating is required)…” The exceptions did not pertain to the accident flight because the pilot was not conducting the flight operation under a part 119 certificate holder. AIRCRAFT INFORMATIONThe Robinson R44 Raven II helicopter was manufactured in 2005 and was equipped with its original Lycoming IO-540-AE1A5 engine. The tachometer time at the accident site was 3,231.3 hours. According to inspection and maintenance records, the last 50-hour engine inspection was completed on October 08, 2019, at a tachometer time of 3,195.4 hours, 35.9 hours before the accident; the last 100-hour airframe inspection was completed on September 28, 2019, at a total time of 3,144.5 hours.

Governor and Tachometer System

The collective control for the accident helicopter was conventional and included a twist grip throttle. When the collective control is moved upward, the engine throttle is opened automatically by an interconnecting linkage. The helicopter was equipped with an engine governor system, which sensed engine rpm and applied corrective input forces to the throttle to maintain engine rpm as needed.

The governor system comprised a solid-state electronic controller, which determined engine rpm from the tachometer points in the engine's right magneto. When the governor sensed the need to adjust engine rpm, it activated a motor which drove the throttle directly. The governor system was designed to assist the pilot in controlling the rpm in the normal operating range. It may not prevent over- or under-speed conditions generated by aggressive flight maneuvers.

The helicopter was equipped with one electronic dual (engine and rotor) tachometer. The sensor for the engine tachometer is the same set of magneto breaker points used by the governor. The sensor for the rotor tachometer is an electronic Hall effect device, which senses passage of two magnets attached to the main rotor gearbox input yoke assembly. (see figures 3 and 4 below.) Robinson personnel reported that, with only one magnet installed, the main rotor tachometer rpm would indicate about 50% of the actual rotor rpm and the low-rotor rpm horn would sound. The normal rotor/engine rpm is 102% on the tachometer and the lowest numeric marking is “50,” with two graduated lines beneath.

Figure 3: Rotor Tachometer Assembly

Picture 4: Location of Rotor Tachometer Assembly

Low Rotor RPM Recovery Procedure

According to the R44 Pilot’s Operating Handbook (POH), the recommended procedure to recover from a low rotor rpm warning condition (warning horn and caution light) was as follows: To restore rpm, lower collective, roll throttle on and, in forward flight, apply aft cyclic. According to Robinson, lowering the collective lever will reduce the power required by the rotors to aid the recovery of rotor rpm; however, in the R44 helicopter, the correlator will decrease the throttle when the collective is lowered and reduce engine rpm (by a few percent) unless the pilot or rpm governor system rotates the twist grip to roll throttle on. AIRPORT INFORMATIONThe Robinson R44 Raven II helicopter was manufactured in 2005 and was equipped with its original Lycoming IO-540-AE1A5 engine. The tachometer time at the accident site was 3,231.3 hours. According to inspection and maintenance records, the last 50-hour engine inspection was completed on October 08, 2019, at a tachometer time of 3,195.4 hours, 35.9 hours before the accident; the last 100-hour airframe inspection was completed on September 28, 2019, at a total time of 3,144.5 hours.

Governor and Tachometer System

The collective control for the accident helicopter was conventional and included a twist grip throttle. When the collective control is moved upward, the engine throttle is opened automatically by an interconnecting linkage. The helicopter was equipped with an engine governor system, which sensed engine rpm and applied corrective input forces to the throttle to maintain engine rpm as needed.

The governor system comprised a solid-state electronic controller, which determined engine rpm from the tachometer points in the engine's right magneto. When the governor sensed the need to adjust engine rpm, it activated a motor which drove the throttle directly. The governor system was designed to assist the pilot in controlling the rpm in the normal operating range. It may not prevent over- or under-speed conditions generated by aggressive flight maneuvers.

The helicopter was equipped with one electronic dual (engine and rotor) tachometer. The sensor for the engine tachometer is the same set of magneto breaker points used by the governor. The sensor for the rotor tachometer is an electronic Hall effect device, which senses passage of two magnets attached to the main rotor gearbox input yoke assembly. (see figures 3 and 4 below.) Robinso...