Accident Details
On June 9, 2012, at approximately 1900 mountain daylight time, a Robinson R44 II helicopter, registration N744JS, was substantially damaged when it impacted terrain after a loss of lift during takeoff/initial climb from the Dona Ana County Airport (5T6) in Santa Teresa, New Mexico. The helicopter was registered to S M Hentges & Sons of Jordan, Minnesota. All three occupants—the private helicopter pilot and his two passengers, both of whom held helicopter pilot certificates—were not injured. Visual meteorological conditions prevailed, and no flight plan was filed. The cross-country flight was conducted under 14 Code of Federal Regulations Part 91, with an intended destination of Roswell, New Mexico, for that leg. The helicopter had just been refueled at Santa Teresa after an uneventful flight from Chino, California. One passenger, a certified flight instructor (CFI) seated in the left seat, stated that the helicopter was about 76 pounds under its maximum gross weight after refueling. Density altitude was approximately 6,800 feet, with wind from 210 to 260 degrees at 10 to 18 knots at takeoff.
Sequence of Events
The pilot, who owned the helicopter, lifted into a 2-foot hover and departed into the wind. The helicopter entered translational lift, accelerated to about 30 to 35 knots, and reached 10 to 20 feet of altitude. Unexpectedly, the helicopter began to settle, and the low rotor RPM warning light illuminated along with the warning horn. The CFI took control, announcing he had control. He slightly lowered the collective, increased throttle, and added slight aft cyclic to recover main rotor RPM, but was unable to increase it enough to maintain flight. He attempted a controlled landing instead of continuing toward an uncontrolled crash, making a cyclic flare to reduce airspeed. Due to low main rotor RPM, low altitude, and low airspeed, he slowed the helicopter to about 15 to 20 knots before leveling for landing.
The helicopter touched down in rough terrain—gravel, sand, sage brush, and small mounds of dirt. The skids broke off upon hitting a mound of dirt, and the helicopter pitched forward. The main rotor struck the ground and broke off, and the tail boom was severed. The helicopter spun slightly right, struck another mound of dirt, and rolled onto its left side. The distance from initial touchdown to final rest was about 75 to 80 feet. The three occupants evacuated after the helicopter was secured.
The CFI later stated he had never experienced a helicopter lift off, enter translational lift almost immediately, accelerate through 30 knots, appear to make a normal takeoff, and then suddenly settle so abruptly. He noted that the pilot/owner and his wife were fairly new helicopter pilots who had trained at a reputable facility, and he considered them competent. The CFI was asked to accompany them due to the trip's length and to provide instruction on the Garmin 430. The pilot/owner and his wife alternated legs as pilot-in-command on the trip, with the CFI in the left seat. The flight was not instructional; the CFI was a friend and passenger.
Examination and Comments
After the accident, examination of the helicopter's engine, airframe, and flight controls revealed no evidence of preimpact mechanical malfunction or abnormalities that may have contributed to the loss of main rotor RPM and settling. The refueling source was tested and found to be within specifications and clear of contaminants; the helicopter's fuel filter screens were clean.
Discussion with the fuel service owner after the accident raised the possibility of whirlwinds (dust devils). The CFI had observed many whirlwinds during the day's flight across southwest desert areas and had turned to avoid several. He did not observe whirlwinds in the takeoff path but noted one could have been starting or ending, which might contribute to rapid decay in rotor RPM.
The initial accident report came from a freight train engineer. The train was crossing about 30 to 50 yards in front of the takeoff flight path. The CFI noticed the train in his peripheral vision and hypothesized that the train could have blocked enough of the relative headwind component to affect the takeoff. The train traveled west to east and passed in front of the takeoff path around the time the helicopter began to settle. The CFI believed the train may have blocked some headwind, causing airflow to burble and settle into a downdraft, potentially causing the loss of rotor RPM and the helicopter to settle.
On the NTSB Form 6120 Recommendation Section, the CFI and pilot suggested the accident could have been prevented by operating at a lighter takeoff weight or waiting for cooler morning temperatures and lower density altitude. They noted the helicopter was within operating and gross weight limits but close to maximum. They stated wind gusts were a factor and that loss of headwind component caused settling. They believed the collective was likely raised to compensate, leading to loss of main rotor RPM and power, making recovery impossible.