Colorado Spring, CO, USA
N2FY
Beech S35
The airplane impacted terrain following the flight instructor and pilot's improper decision to continue the attempted high altitude takeoff when the best rate-of-climb airspeed (Vy) was not obtained, and failure to abort the takeoff. The instructor and private pilot receiving mountain flying instruction stated that, prior to takeoff, the run-up revealed no anomalies, the mixture setting was double checked, and the proper high altitude takeoff procedures were reviewed. The pilot said that he rotated at an airspeed of 70 knots after a ground roll of approximately 2500-3000 feet, which was consistent with their earlier performance calculations. The instructor said she was "looking outside to count runway stripes and to observe take-off profile" during the takeoff roll. The pilot reported holding the aircraft in ground effect to accelerate to the target speed of 96 knots. However, the airplane settled back to the runway, and lifted off again, at an airspeed of 80 knots. The airplane reached the end of the 11,021 foot runway at an altitude of approximately 150-200 feet, and an airspeed of 70-80 knots. As the airspeed began to decay, the pilot lowered the nose to avoid a stall. The pilot initiated an off-field landing with the aircraft touching down in a wings level attitude. Examination of the airframe and engine following the accident revealed no anomalies that would have precluded normal operation. The takeoff performance chart for the airplane indicated that under the atmospheric conditions present at the time of the accident a ground roll of approximately 1,300 feet was required with no obstacle, and a distance of approximately 2,000 feet was required to takeoff and climb over a 50 foot obstacle . The calculated accelerate-stop distance, which was the distance required to takeoff and climb over a 50-foot obstacle and the distance required to land over a 50-foot obstacle, was approximately 3,500 feet. The calculated rate of climb was approximately 1,050 feet. The pilot stated in the accident prevention section of the NTSB accident report that he could have aborted the takeoff; however, the aborted takeoff may have incurred damage to the airplane.
On June 11, 2005, at 0735 mountain daylight time, a Beech S35 single-engine airplane, N2FY, was substantially damaged when it impacted terrain during takeoff from the City of Colorado Springs Municipal Airport (COS), Colorado Springs, Colorado. Visual meteorological conditions prevailed at the time of the accident. The instructional flight was being conducted under the provisions of 14 CFR Part 91 without a flight plan. The flight instructor and private pilot receiving instruction were not injured. The flight was originating from COS at the time of the accident and was en route to Salida, Colorado. The private pilot was attending a mountain flying seminar sponsored by the Beechcraft Pilot Proficiency Program. The ground school portion of the seminar was taught the day prior to the accident. During the ground school, the instruction staff and pilot reviewed "in great detail" the flight route, headings, possible altitudes, and operations. On the day of the accident, the pilot met with his instructor prior to the flight to discuss operational procedures, and check the weather and airplane performance tables. He said that he calculated the aircraft to be "at least 400 pounds below max gross weight at takeoff." In addition, prior to the flight, the instructor and the private pilot discussed who was pilot-in-command. According to the private pilot, he was going to be pilot-in-command; however, the instructor would be providing instruction on mountain flying maneuvers and procedures, which included the high altitude takeoff from COS. The pilot stated that during the pre-takeoff check, "we once again went over the proper leaning procedure and leaned to 100-150 degrees Fahrenheit rich of peak exhaust gas temperature (EGT), which would produce max power. The mag check, vacuum, alternator, and prop cycle were all normal, and the engine instrument parameters were all appropriate." In a statement submitted by the instructor, she stated that prior to takeoff, "all systems were normal and two leaning checks were done, noting the engine sound and EGT." She said they then reviewed the high altitude takeoff procedure to be used; "hold brakes, check engine instruments, release brakes, after rotation, lower nose, accelerate in ground effect, reach Vy or better, positive rate of climb, then climb out." The pilot said that they positioned the aircraft on runway 35L and set the engine controls to "2700 RPM and 23 inches of manifold pressure (MP), indicating a full power takeoff at this altitude." Prior to releasing the brakes, the pilot glanced again at the EGT gauge and noted the mixture control position was approximately two finger widths from the stop when leaned properly. The pilot had been told in the ground school that he would notice three finger widths from the full rich stop when departing at the higher elevation of Leadville, Colorado. The pilot reported, "This mixture position and EGT were appropriate for the lower elevation of [Colorado Springs]." The pilot and instructor estimated that "a 2500-3000 foot roll would be needed before rotation." The instructor stated that during the takeoff roll, she was "looking outside to count runway stripes and to observe take-off profile" while the pilot monitored the gauges and stayed on runway centerline. The pilot reported rotating at 70 knots, approximately 2500-3000 feet down the runway, and verified the power setting of 23 inches MP and 2,700 RPM. The aircraft accelerated to 80 knots in ground effect, with a target airspeed of 96 knots (Beechcraft published best rate-of-climb airspeed (Vy)). As the pilot released back pressure on the yoke to hold in ground effect, the airplane momentarily settled back on the on to the main wheels. The airspeed came back to 80 knots and the airplane was again in ground effect. The airplane "sluggishly accelerated to 85 knots. The power settings were still at full power, and [the airplane] may have gotten up to 90 [knots], and we had gained approximately 100 feet of altitude." As the airplane passed the end of the 11,021-foot runway, the airspeed was 70-80 knots. The pilot estimated that the airplane never gained more than 150-200 feet of altitude. The airspeed began to decay so he let the airplane's nose drop a little to maintain a speed above stall. The pilot stated the airplane was "not able to climb," and he looked for a place to land. The pilot aimed the airplane between two light poles, and the aircraft "hit the ground with wings level, skidded across a highway, coming to rest in a grassy median. According to the NTSB Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), Section "Recommendation (How Could This Accident Have Been Prevented)", the pilot reported, "Everything seemed normal on take-off until we reached 80-85 KIAS, then, engine was running smoothly, but we could not climb, then airspeed began to decay. We could have maybe aborted [takeoff] but we would have run off the end of the runway and into a fence and other obstacles." At 0754, the COS (elevation 6,184 feet) automated surface observing system reported the wind from 270 degrees at 4 knots, visibility 10 statute miles, sky clear, temperature 11 degrees Celsius, dew point 3 degrees Celsius, and an altimeter setting was 29.95 inches of mercury. The density altitude calculated by the NTSB was 7,228 feet. The NTSB examined the airframe and engine at the facilities of Beegles Aircraft Services, Greeley, Colorado. Examination of the airplane revealed the landing gear were separated, the firewall was buckled, and the propeller blades were bent. No anomalies were noted with the airframe that would have precluded operation of the flight controls. Examination of the engine revealed no anomalies that would have precluded normal operation. According to the Beechcraft S35 Pilots Operating Handbook (POH), Normal Procedures, Before Takeoff checklist, the mixture setting position is "FULL RICH (or as required by field elevation)." According to the takeoff performance chart in the Beech S35 POH, at a temperature of 11 degrees Celsius, pressure altitude of approximately 6,150 feet, and a weight of approximately 2,900 pounds, a takeoff ground roll of approximately 1,300 feet was required with no obstacle, and a distance of approximately 2,000 feet was required to takeoff and climb over a 50-foot obstacle. The calculated accelerate-stop distance, which was the distance required to takeoff and climb over a 50-foot obstacle and the distance required to land over a 50-foot obstacle, was approximately 3,500 feet. According to the climb performance chart in the Beech S35 POH, at the conditions listed for the takeoff performance calculations, the calculated rate of climb with the power at full throttle at 2,700 RPM, mixture leaned to appropriate fuel flow, flaps up, landing gear up, climb speed 96 knots, and cowl flaps as required, was approximately 1,050 feet per minute.
the flight instructor and pilot's improper decision to continue the attempted high altitude takeoff when Vy airspeed was not obtained, and failure to abort the takeoff which resulted in an off-field landing and subsequent impact with terrain. A contributing factor was the flight instructor's inadequate supervision during the attempted high altitude takeoff.
Source: NTSB Aviation Accident Database
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