Bermuda Dunes, CA, USA
N9YY
MOUL WILLIS RV-3
The pilot departed on a local flight in the experimental, amateur-built airplane. Flight track information indicated that the airplane departed and climbed to a maximum altitude of about 712 ft above ground level. One witness saw the airplane and described the engine noise as loud. As the airplane turned toward her location, she saw that the propeller blades were spinning slower than she thought they should. Another witness, who was closer to the accident site, saw the airplane at low altitude but could not hear the engine noise. A third witness captured video showing the airplane first in level flight, then its pitch attitude increased, and the airplane entered a right bank. The right bank continued past 90° as the airplane entered a nose-low descent. The airplane impacted a palm tree about 35 ft agl about 3 minutes after takeoff and came to rest upright in the driveway of a private residence. Examination of the airframe and engine revealed no mechanical anomalies that would have precluded normal operation; however, the fuel shutoff valve was found in an intermediate position that restricted fuel flow about 50%. Based on the available information, it is likely that the pilot’s improper positioning of the fuel shutoff valve resulted in fuel starvation and a total loss of engine power during the takeoff climb as evidenced by the absence of engine noise in the witness video. The pilot subsequently exceeded the airplane’s critical angle of attack, resulting in an aerodynamic stall/spin and loss of control.
On December 11, 2021, about 1230 Pacific standard time, an experimental, amateur-built RV-3 airplane, N9YY, was substantially damaged when it was involved in an accident near Bermuda Dunes, California. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to a friend who had spoken to the pilot’s wife after the accident, the pilot planned a local flight, with the intention to overfly his home, located about 2.7 miles southwest of Bermuda Dunes Airport (UDD), Palm Springs, California. A security camera located at UDD, captured the airplane as it lifted off at 1226:17 and flew out of view. Automatic dependent surveillance-broadcast (ADS-B) data provided by the Federal Aviation Administration (FAA) revealed that, at 1226:55 the airplane was about .6 miles southwest of UDD at an altitude of 517 ft above ground level (agl), and on a heading consistent with a track toward the pilot’s residence. The airplane overflew a portion of the city of Bermuda Dunes, California. The airplane maintained the southeast heading for about 1.3 miles. At 1227:22, the airplane overflew a 300-ft-by-900 ft vacant lot. About 10 seconds later, the airplane had reached a maximum altitude of 712 ft agl. Nine seconds later, it had descended to 672 ft agl and began a right turn. The airplane continued the descending right turn until the end of the track data, at 1228:22. At that time, the airplane was on a heading of 124° at a low altitude, about 525 ft north of the accident site, as shown in figure 1. The accident site was immediately north of the vacant lot the airplane had previously overflown. Multiple witnesses saw the airplane in flight. One witness, located about .7 miles west of the accident site, reported that she first heard a loud airplane, then saw it in a descending right turn. She could see the individual propeller blades spinning but not as fast as she thought they should be. Another witness, located about 1,500 ft north of the accident site, reported that he saw the airplane in a normal attitude travelling from north to south at a very low altitude. He could not hear the engine. Another witness, located about 1,000 ft north of the accident site, captured a 10-second video of the airplane just before the accident. The video revealed the airplane in a near-level pitch attitude and traveling to the southeast. No engine noise from the airplane was heard. The airplane’s pitch attitude increased, and the airplane entered a right bank. The last moments of the video revealed the airplane in a right bank angle exceeding 90° as the nose dropped. Figure 1. Overhead view of the ADS-B flight track. A vacant lot is identified by a yellow border. The airplane came to rest upright on a residential driveway about 1.3 miles southwest of UDD. The first point of impact was a palm tree about 35 ft in height located about 50 ft north of the wreckage. The top portion of the palm tree lay adjacent to the airplane and one of the airplane’s wooden propeller blades was located at the base of the tree. All major structural components remained attached to the airplane and flight control continuity was established to all flight control surfaces. The forward engine cowling area exhibited crush damage with embedded palm fronds. There was crush damage of the fuselage, aft of the firewall, that extended to the cockpit area. The right wing exhibited substantial damage to the leading edge. The left wing exhibited substantial damage to the leading edge near the root. The empennage exhibited only minor damage. Postaccident examination revealed a fuel shutoff valve mounted to the underside of the breached fuel tank. The fuel shutoff valve handle had no markings to identify an open or closed position, and it was positioned 90° to the fuel line. (see figure 2). The valve was disassembled and examined. When viewed through the fuel passage, and the valve handle was set at 90° to the fuel line; the fuel passage was open about 50%. When the handle was moved aft to the 135° position; the fuel flow was shut off. When the handle was pushed forward to the 45° position, the fuel passage was open 100%. According to a first responder, he did not see anyone manipulate the fuel shutoff valve following the accident. He reported that, by the time they arrived, all the fuel had drained from the fuel tank, and no one was worried about closing a fuel shutoff valve. According to recovery personnel, about 8 gallons of fuel drained out of the tank after the accident. Postaccident examination of the airframe and engine revealed no mechanical malfunctions or failures that would have precluded normal operation. Figure 2. Image of the fuel shutoff valve as found at the accident site.
The pilot’s improper positioning of the fuel shutoff valve, which resulted in a loss of engine power, and the pilot’s subsequent exceedance of the airplane’s critical angle of attack, resulting in an aerodynamic stall and loss of control.
Source: NTSB Aviation Accident Database
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