History of Flight
On July 1, 2015, at approximately 1704 eastern daylight time, a Piper PA-28-151, registration N43503, was substantially damaged when it impacted terrain while on approach to Twin Country Airport (HLX) in Galax Hillsville, Virginia. The commercial pilot sustained a minor injury, and the pilot-rated passenger was not injured. The airplane was privately owned and operated under 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from New River Valley Airport in Dublin, Virginia, about 1643, and was destined for HLX.
The pilot reported that after takeoff he flew towards HLX, and the wind direction favored landing on runway 19. He entered a midfield left downwind leg of the traffic pattern for runway 19. When the airplane was "abeam the numbers," he lowered the flaps to the first notch (10 degrees), set the mixture to full rich, and descended 300 feet, but did not turn on carburetor heat. He turned onto the base leg and then onto a short final approach leg for landing. The airplane was 500 feet above ground level (agl) at an airspeed of 80 mph, and the next thing he knew they were on the ground. He indicated the engine was "running OK" and did not sputter or experience power loss. He believed the airplane may have descended due to a microburst, but when asked about a rain shower nearby, he reported "no." He also indicated that when the airplane was low to the ground, the passenger put his hand on top of his on the throttle and added full power, but it was too late. He stated he did not stall the airplane. On the NTSB report form, the pilot indicated no mechanical failure or malfunction.
The pilot-rated passenger stated that the pilot listened to the automated weather observing system (AWOS) prior to entering the traffic pattern, and the winds were variable across the runway at 7 to 10 mph. The passenger indicated the pilot entered the traffic pattern for runway 01 at 3,400 feet mean sea level (msl) at 100 mph, then decided to fly across midfield to look at the windsock and elected to land on runway 19. The passenger noted everything seemed normal except for being lower than traffic pattern altitude, but that was typical for the pilot. The passenger became preoccupied with an iPad, noticed a drop in engine rpm as the pilot turned onto final approach, looked up and saw terrain but not the runway, saw no irregularity on gauges, instantly grabbed the pilot's hand and pushed the throttle, and almost simultaneously felt a tremendous impact. They exited after the airplane came to rest.
A witness saw the airplane fly over the runway at midfield in a steeper than normal left bank, estimated altitude between 200 and 250 feet agl. About one minute later, the witness was notified that the airplane may have crashed.
Meteorological Information
An AWOS report at the accident airport at 1655 indicated wind from 240 degrees at 7 knots, visibility 10 statute miles, broken clouds at 4,800, 5,000, and 11,000 feet agl. Temperature and dew point were 25°C and 16°C, altimeter 30.00 inches of mercury. No significant precipitation was detected. No indication of microburst activity or outflow boundaries within 10 miles of the accident site.
Upper air soundings from Roanoke/Blacksburg at 1900 depicted a destabilizing atmosphere with Lifted Index -3, supporting scattered thunderstorms and rain showers. Estimated cloud base near 4,000 feet agl. Both soundings showed light low-level wind shear below 800 feet agl with approximately 15 knots shear. No pilot reports of low-level wind shear, but moderate turbulence at 7,000 feet was reported.
Additional Information
The airplane was equipped with a portable Garmin 396 GPS receiver. The GPS data was downloaded and showed the flight path. On the downwind leg between 1703:07 and 1703:34, groundspeed slowed from 80 knots to 65 knots (about 75 mph). The airplane turned onto base leg, climbed slightly to 2,831 feet GPS altitude (about 190 feet above runway elevation), then turned onto final approach, descended to 2,618 feet (near ground level), and slowed to 62 knots groundspeed (about 71 mph). The last valid data point at 1703:53 placed the airplane about 470 feet from the approach end of runway 19.
Weight calculations using the airplane's empty weight (1,477.2 pounds), pilot and passenger weights (174 and 261 pounds per last medical exams), and estimated fuel burn resulted in a gross weight of about 2,184 pounds at the time of the accident.
Stall speed information from the Pilot's Operating Manual (POM) indicates the power-off stall speed with no bank and flaps retracted was approximately 64 mph at the calculated weight. The POM did not specify stall speeds for partial flap settings other than retracted or fully extended.
An NTSB performance study using GPS data and winds aloft of 7 knots from 240 degrees estimated that the airplane slowed on the downwind leg. At the last point before turning onto final, the equivalent airspeed was 65 mph. The next two calculated airspeeds showed continued slowing through the turn. Based on a 65 mph turn radius, the necessary bank angle was about 27 degrees. Extrapolating stall speed for that bank angle yielded 69 mph for flaps up and 62 mph for flaps down. Since the airplane was lighter than gross weight, stall speeds were estimated to be 2 to 3 mph slower (67 and 60 mph, respectively).