Accident Details
Probable Cause and Findings
The pilot's loss of control resulting in inadvertent stall/mush during initial climb following takeoff. Factors were the unfavorable, sudden windshift conditions, the high density altitude, and the manufacturer's failure to provide adequate density altitude performance information in the Airplane Flight Manual.
Aircraft Information
Registered Owner (Historical)
Analysis
On August 31, 1999, approximately 1215 mountain daylight time, a Piper PA-28-180, N5172L, registered to and operated by Falls Aero, Inc., Great Falls, Montana, was destroyed when it collided with terrain during initial climb following takeoff from Meadow Lake Airport, Peyton, Colorado. The private pilot and one passenger received minor injuries; however, two other passengers were seriously injured. Visual meteorological conditions prevailed, and a VFR flight plan had been filed for the personal cross-country flight being conducted under Title 14 CFR Part 91. The intended destination was Laramie, Wyoming.
According to the pilot, he arrived at the airport on the evening of August 29 and requested the fuel tanks to be filled "to the tabs," which equates to 36 total gallons of fuel, 18 gallons per tank. The maximum fuel capacity in the airplane is 50 gallons. During the preflight prior to departure on the morning of the accident, he noted that the aircraft's battery was dead, and had it replaced. Prior to taxiing for takeoff, he observed the winds to be out of the northwest at 10 knots, and he selected runway 33 for departure. According to him, he performed a density altitude calculation using a temperature of 81 degrees F. He did not indicate on his accident report what altimeter setting he used; however, using the reported altimeter setting of 30.10 Hg at Colorado Springs, the closest weather reporting facility, the computed density altitude was 9,747 feet above mean sea level (msl).
Prior to departure, the pilot applied 10 degrees of flaps. During takeoff, the ground roll was "normal," and he climbed out at 80 mph (normal climb speed in the PA-28-180). According to him, "after climbing over buildings and trees the airspeed suddenly dropped to 60 mph and [the] engine began to labor." He lowered the nose to gain airspeed and retracted the flaps. As the aircraft approached power lines, the pilot elected to fly under them. Shortly thereafter, the aircraft impacted slightly inclining terrain. Upon impact with the ground, the four occupants exited the aircraft, and the airplane was subsequently consumed by fire.
According to a witness on the ground, he observed N5172L positioned at the end of runway 33 prior to departure. At that time, he noted the winds to be out of the west/southwest at 10 knots. He did not see the aircraft depart the runway; however, he next observed the aircraft at 50 to 70 feet above ground level (agl) about 200 feet south off the departure end of runway 33 "flying at a very nose-high attitude, with an unusually low ground speed and its wings rocking slightly as if on the verge of a stall." He then observed the aircraft begin to lose altitude. He stated that the aircraft appeared to maintain its nose-high attitude until it disappeared from his view behind the trees 1,500 feet and slightly to the left of centerline off the end of runway 33.
At 1154, the reported weather conditions at Colorado Springs, located 10.4 nm to the southwest, were winds from 110 degrees at 7 knots. At 1254, the winds were variable at 4 knots. According to an FAA inspector who attended the scene following the accident, several pilots in the area near the time of the accident reported encountering variable and shifting wind conditions. Shortly after the accident, the airport's active runway switched to 15.
According to an engineering representative with The New Piper Aircraft Corporation, the climb performance provided in the 1967 Airplane Flight Manual at 7,000 feet with 0 degrees of flaps should provide a climb rate of 400 feet per minute. Performance data in the manual provides information on takeoffs with 0 and 25 degrees flaps. Also, the manual states that takeoffs are to be made with flaps in the UP position; however, "to shorten takeoff distance, flaps up to 25 degrees may be used." There is no performance data in the manual for takeoffs above 7,000 feet density altitude.
Using average weights for the four occupants, 36 gallons of fuel, a temperature of 84 degrees F. and the aircraft's empty weight of 1,301 lbs., the gross weight of the aircraft was calculated to be 2,197 lbs., which is under the maximum gross takeoff weight of 2,400 lbs. The total weight of the baggage, if any, is unknown. The aircraft's center of gravity (cg) was also calculated to be 91.72 inches aft of datum, which is within the allowable cg range of 84.0 to 94.5 inches.
According to calculated performance data, under no wind conditions, the aircraft would require a ground roll of 1,550 ft. and 2,700 ft. to takeoff and climb to a distance of 50 ft. above ground level (agl). With a 10 knot headwind, the ground roll distance would be 1,325 ft. with a distance to climb 50 ft. agl of 2,400 ft. Lastly, with a 10 knot tailwind, the ground roll would be 1,775 ft. with 3,000 ft. required to climb to 50 ft. agl. Runway 33 at Meadow Lake is 6,000 feet.
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# DEN99LA156