Florence, CO, USA
N5969W
Piper PA28
During takeoff for a local flight, the flight instructor rotated the airplane, but it failed to lift off from the runway. The flight instructor continued the takeoff and rotated the airplane a second time; at that point, the airplane was located near the midpoint of the runway. A witness reported that the airplane’s climb performance was weak. During the climb, the flight instructor recognized that something was wrong and made a 180° turn to land on the runway. The airplane impacted terrain resulting in substantial damage to both wings and the fuselage. Postaccident examination of the airframe and engine found no preimpact anomalies that would have precluded normal operations. A review of meteorological data revealed that the temperature at the time of the accident was the warmest that the pilot had encountered since he purchased the airplane 1 month before the accident. The weather conditions at the time of the accident were consistent with a high density altitude; well above the threshold indicated in guidance at which leaning the fuel mixture is recommended to maintain airplane performance. Postaccident calculations showed that, in the weather conditions at the time, the airplane would have experienced a takeoff distance increase of 140% and a climb performance decrease of 65%. It is not possible to determine, based on the available evidence, whether the instructor adequately leaned the airplane’s fuel mixture for departure and whether that contributed to degraded airplane performance. During a previous flight, the airplane exhibited reduced performance while operating in lower density altitude conditions than those on the day of the accident.
HISTORY OF FLIGHTOn February 2, 2020, about 1355 mountain daylight time, a Piper PA28-150 airplane, N5969W, was substantially damaged when it was involved in an accident near Florence, Colorado. The flight instructor and one passenger were seriously injured, and one passenger was fatally injured. The airplane was operated under the provisions of Title 14 Code of Federal Regulations Part 91 as an instructional flight. The flight was a second exploration flight for the passenger seated in the front left seat. The brother of that person was seated in the aft right seat, and the flight instructor was seated in the front right seat. The flight instructor reported that he rotated the airplane using about 2,000 ft of the 5,399-ft-long runway. The airplane climbed and then settled back down to the runway. About 2,500 ft down the runway, the flight instructor rotated the airplane again and entered ground effect. He did not recall the climbout but remembered that he flew a 180° turn to land on runway 11. The airplane descended and impacted rolling terrain about 1,000 ft southwest of the departure end of runway 29. An eyewitness saw the accident airplane depart from about midfield. He recalled that the airplane sounded as if it were making the expected power but that the subsequent climb was “anemic.” PERSONNEL INFORMATIONThe flight instructor purchased the airplane on December 31, 2019, about 1 month before the accident. In addition to logging flight time in the accident airplane the flight instructor had logged time in Cessna 210-5A, Piper PA28-180, and Cessna 182T airplanes. AIRCRAFT INFORMATIONAccording to the most recent weight and balance information, the accident airplane was operated about 100 pounds below maximum gross weight. METEOROLOGICAL INFORMATIONThe calculated density altitude at the airport was 7,931 ft. At the time of the accident, the weather observation at the airport indicated a temperature of 24ºC/75ºF. According to the flight instructor, it was the highest temperature at 1V6 since his purchase of the accident airplane. The recorded dewpoint was -15ºC/5 ºF and the barometric pressure was 29.78 in of mercury. Using the Koch Chart located in the Federal Aviation Administration’s Density Altitude document, the airplane would be expected to experience a takeoff distance increase of 140% and a climb performance reduction of 65%. AIRPORT INFORMATIONAccording to the most recent weight and balance information, the accident airplane was operated about 100 pounds below maximum gross weight. WRECKAGE AND IMPACT INFORMATION Figure 1 Accident Site Plots The initial impact point was determined to be scuffing along the ground that went up an embankment along a 125° magnetic heading. The airplane came to rest upright on a 347° magnetic heading. The left wing had separated and was broken in several locations. The left wing fuel tank was breached but contained some fuel. The right wing remained attached to the airplane, and the fuel tank contained fuel. About 20 to 25 gallons of fuel was drained from airplane. The tachometer displayed 2,995.81 hours, and the Hobbs meter showed 610.4 hours. Flight control continuity was traced from the flight controls to the control surfaces. The flap handle was set to the first notch, which corresponded to 10° flap extension. The trim screw displayed about 1 inch (7 threads visible) approximating a neutral-to-nose-up pitch trim setting. The propeller remained mounted to the engine crankshaft flange. The spinner was crushed aft against the propeller hub. One propeller blade was bent aft about 90° with chordwise polishing observed, and some leading-edge denting and chipping were noted. The other blade was straight and showed no evidence of scraping and chipping. All engine filters and screens were clear of debris. Valve train continuity and thumb compression were obtained for each cylinder. The magnetos produced spark at each terminal. The carburetor had separated and showed signatures of hydraulic pressure to one of the floats, consistent with fluid (fuel) being present in the carburetor at impact. No preimpact anomalies were detected with the airframe or engine. ADDITIONAL INFORMATION FAA-P-8740-2, “Density Altitude” The Federal Aviation Administration’s density altitude document (FAA-P-8740-2), dated 2008, stated the following: Whether due to high altitude, high temperature, or both, reduced air density (reported in terms of density altitude) adversely affects aerodynamic performance and decreases the engine’s horsepower output. Takeoff distance, power available (in normally aspirated engines), and climb rate are all adversely affected. Landing distance is affected as well; although the indicated airspeed (IAS) remains the same, the true airspeed (TAS) increases. From the pilot’s point of view, therefore, an increase in density altitude results in the following: • Increased takeoff distance. • Reduced rate of climb. • Increased TAS (but same IAS) on approach and landing. • Increased landing roll distance. In addition:If the airplane flight manual (AFM)/POH [Pilot’s Operating Handbook] is not available, use the Koch Chart to calculate the approximate temperature and altitude adjustments for aircraft takeoff distance and rate of climb. At power settings of less than 75 percent, or at density altitude above 5,000 feet, it is also essential to lean normally aspirated engines for maximum power on takeoff (unless the aircraft is equipped with an automatic altitude mixture control). Otherwise, the excessively rich mixture is another detriment to overall performance. Video of Earlier Flight A student pilot, who had flown in the accident airplane with the flight instructor about 1 month before the accident, provided a video of that flight. The student said that the flight included the flight instructor, himself, and a passenger. The airplane was fueled with 20 gallons. The video showed that, when the airplane was rotated at a speed of about 72 mph, the stall warning light illuminated and continued to flicker as the airplane climbed and accelerated toward 85 mph. The student pilot then asked if “that” was normal; the flight instructor replied, “yeah, it’s pretty sensitive but we are nowhere near a stall.” Later during the climbout, the flight instructor remarked that the airplane “is not climbing today.” A review of weather information for that flight showed that the temperature was 46.4°F with a pressure altitude of 5,122 ft. The Koch Chart showed a decrease in climb performance of about 50%.
The pilot’s decision to continue the takeoff with reduced airplane performance due to high density altitude
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
