DAWSON, MD, USA
N29832
Piper J3C-65
Three Piper J3s, departed an airport in a valley with higher terrain nearby, and a density altitude of about 3,000 feet. Each airplane turned toward rising terrain, consisting of lower finger ridges and canyons, and a higher main ridge. The first airplane carrying only a pilot climbed faster than the terrain, and turned downwind. The second and third airplanes each carrying a pilot and passenger, tried to follow similar paths. The second airplane was at gross weight, and the pilot reported he encountered descending air which drove him down into the trees. The pilot reported no engine or airplane problems. The airplane was equipped with a cruise propeller which increased cruise speed and decreased the airplane's rate of climb. The pilots had been briefed on alternate departure routes that would not have required an immediate climb over rising terrain, but they were not used. FAA publications advised of the need to download weight when operating with higher density altitudes, and to approach ridgelines at a 45 degree angle to allow for escape in case of turbulence or descending air.
HISTORY OF FLIGHT On June 26, 1999, about 1230 eastern daylight time, a Piper J3C-65, N29832, was substantially damaged when it struck terrain in Dawson, Maryland. The certificated commercial pilot and the passenger received serious injuries. Visual meteorological conditions prevailed for the flight destined for New Castle, Virginia. No flight plan had been filed for the personal flight that was conducted under 14 CFR Part 91. About 0930, a flight of four Piper J3s left Lock Haven, Pennsylvania, where the pilots and passengers had been attending a Piper Cub fly-in. The four airplanes arrived at High Rock Airport, Dawson, about 1120. One airplane remained at High Rock Airport and the other three airplanes were serviced with Amoco low lead automobile gasoline, which was transported to the airport in cans. The airport owner reported that he briefed the pilots on the airport departure procedures, and the pilots elected to depart to the north. According to witnesses, the wind varied between calm and favoring a north departure. The first airplane to depart, a Piper J3C-65, N30362, carried only the pilot. The second airplane to depart, N29832, carried a pilot and passenger. The third airplane to depart, a Piper J3C-85, N1548N, carried a pilot and a passenger. The pilot of N30362 reported that he departed to the north and made a left turn after he passed the departure end of the runway. He thought the temperature was at least 90 degrees Fahrenheit or greater. There were no topographic winds, and a few weak thermals were present. The terrain to the west of the airport was higher. The pilot of N30362 reported that he was climbing better than the other two airplanes. He observed N29832 operating just above the trees and then saw it strike trees before descending to the ground. The pilot of N1548N reported that he noticed as N29832 was falling out of the sky, it "waffled" with the wings rocking from side to side as it descended into the trees. He had his door open as he flew over N29832, and could see both occupants moving about. The accident was also observed by the High Rock Airport owner who reported that he saw N29832 operating just above the trees and then the airplane pitched nose down into the trees. When interviewed, the pilot of N29832 reported that his climb was slower than normal, but the airplane was performing well, and there were no problems with the engine. He preferred to climb about 50-55 mph, but was climbing closer to 45 mph. The airplane had the correct pitch attitude to climb, but was not climbing. The pilot tried to position the airplane over lower terrain. With the airplane still in a climb pitch attitude, it started to descend. The pilot rechecked the throttle full open, and that the carburetor heat was off. He turned right followed by a shallow left turn, in an attempt to position the airplane over lower terrain. He was aware that an abrupt control movement could induce a stall/spin and flew accordingly. When the airplane was about 100 feet AGL, he leveled the wings, then lowered the right wing slightly. The airplane struck branches and fell to the ground on its right side. The pilot assisted his passenger in exiting the airplane. A few minutes later he saw an airplane fly over his position. He then awaited the arrival of emergency personnel. The accident occurred during the hours of daylight at 39 degrees, 29.16 minutes north latitude, and 78 degrees, 56.88 minutes west longitude. PERSONNEL INFORMATION The pilot held a commercial pilot certificate with ratings for rotorcraft-helicopter, and instrument helicopter. He also held a private pilot certificate with a airplane single engine land rating. He was last issued a 2nd class Federal Aviation Administration (FAA) airman medical certificate on June 1, 1999. According to the NTSB Form 6120.1/2, the pilot's last flight review was conducted on January 25, 1999, in the accident airplane. He listed his total flight experience as 1,760 hours, with 1,035 in single engine airplanes and 680 hours in make and model. He had flown 54 hours, and 15 hours in the preceding 90 days and 30 days respectively. AIRCRAFT INFORMATION The airplane was originally delivered to the US Army Air Corps as a light observation airplane (L4H). In 1945, it was re-certified as a J3C-65. The current configuration of the airplane included a 72 inch diameter propeller with a 44 inch pitch. This was known as a cruise propeller. According to the owner, takeoff from High Rock Airport was conducted with the fuselage tank full of fuel (12 gallons). According to weight and balance data received from the pilot, the airplane weighted 1,214 pounds at takeoff. In the computation the pilot listed his baggage weight as 20 pounds. According to the pilot of N30362, who helped carry the pilot's and passengers baggage from the airplane to the hospital, the weight of the baggage was at least 50 pounds and possibly heavier. When the pilot was interviewed in the hospital on June 27, 1999, a large duffel bag of the pilot's personal property was observed next to the pilot's bed. The maximum allowable weight for the baggage compartment was 20 pounds. The maximum allowable takeoff weight of N29832 was 1,220 pounds. AIRDROME INFORMATION (Departure) High Rock Airport was a non-designated private airport with an elevation of 760 feet above mean sea level. The turf runway was about 1,700 feet long and over 100 feet wide. The runway headings were about 020 and 200 degrees. Examination of the surface revealed it was firm, and the grass was about 2 to 3 inches high. Higher terrain existed to the all quadrants, although there were routes available to the north and south that did not require immediate climbs. The airport owner pointed out that north departures had the option of flying to the right of a 750 feet high obstacle, located about 3,500 feet beyond the departure end of the runway. The best choice was to fly to the right of the obstacle over level terrain while climbing. After passing the obstacle, the valley opened up to allow for maneuvering, including 180 degree turns without flying over higher terrain. A departure to the south would take the airplane next to rising terrain, but not over it. The pilot had the option of following a road and river as the airplane gained altitude. The terrain to the west and north of the airport was rising. A ridgeline was orientated north-east to south-west, and located about 2.3 nautical miles (NM) northwest of the airport. The height of the ridge varied between 2,250, and 2,500 feet. From the ridgeline to High Rock airport, the terrain consisted of descending terrain with elevated fingers and lower level canyons between the fingers. METEOROLOGICAL INFORMATION The surface winds and forecast winds aloft at 925 millibars (MB) (about 2,500 feet), 850 MB (about 4,800 feet), and 700 MB (about 9,900 feet), for western Maryland and surrounding territory were examined. The surface wind chart was a composite of all ground reporting stations in the area. The accident site was in an area of 4 knot winds, and adjacent to an area of 2 knots winds. The winds aloft forecast were produced twice a day, at 0000 UTC (2000 EDT), and 1200 UTC (0800 EDT). At 1200 UTC, the 925 MB winds were from the west between 6 and 8 knots. At 850 MB, the winds were from the north-west at 2 to 4 knots. At 700 MB, the winds were from the south-west at 8 to 10 knots. At 0000 UTC, the 925 MB, 850 MB, and 700 MB winds were from the south at 10 knots, 8 knots, and 12 to 13 knots respectively. The closest weather reporting stations to the accident site were Hagerstown, Maryland, 59 NM to the east, and Morgantown, West Virginia, 46 NM to the west. Both of these stations recorded a temperature of 30 C (86F), at 1253. A local weather observer in Keyser, West Virginia, located 4 statue miles south, southwest of the accident site reported a peak temperature of 92 F. The time of the temperature peak was not recorded. WRECKAGE AND IMPACT INFORMATION Examination of the airplane revealed it came to rest on a heading of 020 degrees. The terrain elevation was about 840 feet, and was sloped about 15 degrees. The accident site was about .75 NM from the departure end of the runway on a magnetic heading of 342 degrees. The outboard half of the right wing was bent up and the right main landing gear had been bent under the fuselage. Flight control continuity was verified between the cockpit controls and all flight control surfaces. Fuel was found in the fuselage fuel tank, the fuel sump, the fuel line between the fuel sump and the carburetor, and in the carburetor. All fuel samples were bright and clear with a pink tint, similar to automobile gasoline. The fuel tank, fuel sump, fuel line, and carburetor were absent of debris. The engine was rotated and compression was present in all cylinders. Spark was obtained from all terminals of the magnetos. ADDITIONAL INFORMATION According to FAA Accident Prevention Program Publication, FAA-P-8740-2, DENSITY ALTITUDE: "...When the temperature rises above the standard temperature for the locality, the density of the air in that locality is reduced and the density altitude increases. This affects the aircraft aerodynamic performance, and decreases the horsepower output of the engine...From the pilot's point of view, an increase in density altitude results in: 1, Increased takeoff distance. 2, Reduced rate of climb...Even at lower elevations, aircraft performance can become marginal and it may be necessary to reduce aircraft gross weight for safe operations...." The density altitude was estimated to be about 3,000 feet at High Rock Airport. According to the Aeronautical Information Manual (AIM); Chapter 7, Safety of Flight; Section 5, Potential Flight Hazards; Paragraph 5, Mountain Flying: "...When approaching a mountain ridge from the downwind side, it is recommended that the ridge be approached at approximately a 45 degree angle to the horizontal direction of the ridge. This permits a safer retreat from the ridge with less stress on the aircraft should severe turbulence and downdraft be experienced...." According to the Chief Engineer for Sensenich Propellers, the manufacturer of the propeller on N29832, they made one model of propeller for the Piper J3C-65. They typically used a 40 inch pitch for climb, a 42 inch pitch for standard conditions, and a 44 inch pitch, for cruise. Changing from a climb to a standard propeller, or from a standard propeller to a cruise propeller, would generally increase the cruise speed about 3 to 5 MPH. However; the tradeoff of higher cruise speed would be offset by decreased climb performance. The 42 inch pitch was recommended for use with low altitude airports. He further stated that the lower the engine horsepower, the more sensitive the airplane's climb performance would be to increased gross weight, density altitude, and reduced engine performance. The third airplane in the flight, N1548N, struck the terrain about 20 seconds after N29832. Reference National Transportation Safety Board accident report NYC99FA161 for the details of that accident. The accident site of N29832 was about 1,900 feet away from the accident site of N1548N, on a magnetic heading of 122 degrees. The airplane was released to the pilot on June 27, 1999.
was the pilot's improper decision to turn toward rising terrain with inadequate terrain clearance. Factors were the density altitude, and unfavorable winds.
Source: NTSB Aviation Accident Database
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