Bisbee, AZ, USA
N5757D
Beech 35-C33
The airplane settled back to the ground during the takeoff initial climb and collided with bushes and desert terrain off the end of the runway, bending the right wing and aft carry-though spars. The airport was at an elevation of 4,780 feet mean sea level (msl) and the density altitude was 6,692 feet msl. During his leaning of the mixture, the pilot set the rpm at 1,800, leaned the mixture for an increase in rpm, then richened the mixture by one full turn, all in accordance with instructions given him during his check-out in the rental airplane by a flight instructor. The pilot completed his pre-takeoff checklist, made a traffic advisory, and positioned the airplane for takeoff. He held the brakes and applied full throttle. As the rpm came up to 2,600 rpm, the engine sounded normal, the brakes were released, and he began the takeoff roll. During the takeoff ground roll, a significantly greater distance was required to develop airspeed than the pilot expected; however, he thought this to be the result of the airport elevation and the outside air temperature. The pilot operating handbook (POH) performance charts showed that a ground roll of 2,100 feet should have been required to achieve takeoff over a 50-foot obstacle. The airplane reached 65 knots approximately 2/3 down the 5,929-foot-long runway and slight elevator back pressure was applied. The airplane lifted off and back pressure was eased to remain in ground effect and continue airspeed acceleration. However, the airplane did not accelerate, but instead settled back to the ground. The airplane touched down just off the end of the runway and came to a stop approximately 20 feet from the airport perimeter fence. The day prior to the accident, the pilot was checked out in the airplane. Following the check-out flight, he asked the certified flight instructor (CFI) the proper leaning procedures for the airplane. He was told to lean the mixture at run-up (1,800 rpm) using engine rpm, and then richen it one full turn at field elevations below 5,000 feet msl, and to lean the mixture at full power using the exhaust gas temperature gauge at field elevations above 5,000 feet msl. The POH states that the engine should be leaned using 2,600 rpm using the combined manifold and fuel flow indicator gauge. This gauge shows fuel flow in gallons per hour and is marked with a green arc to indicate normal fuel flow operating parameters for different power settings. The takeoff optimum fuel performance range is covered by green sectors and the high side of each green sector represents the appropriate fuel setting required to obtain maximum power when operating at full throttle and 2,600 rpm. A Federal Aviation Administration inspector test-ran the engine following the accident and no operational anomalies were noted.
HISTORY OF FLIGHT On September 19, 2005, at 1545 mountain standard time, a Beech 35-C33, N5757D, did not gain altitude during the attempted takeoff and collided with desert bushes off the end of the runway at Bisbee Municipal Airport, Bisbee, Arizona. Chandler Air Service was operating the airplane, that was registered to a private company, under the provisions of 14 CFR Part 91. The private pilot and two passengers were not injured; the airplane sustained substantial damage. Visual meteorological conditions prevailed and a visual flight rules flight plan had been filed. The pilot was initiating the flight at the time of the accident, and his final destination was Chandler Municipal Airport, Chandler, Arizona. The pilot submitted a comprehensive written statement regarding the accident. He reported departing Chandler airport at 0900 after completing weight and balance and performance calculations, and landed at Bisbee airport at 1030. After performing business in Bisbee, he and his passengers returned to the airport at 1530. Prior to the return, the pilot contacted Flight Service where he obtained weather information and filed a flight plan. He also contacted Chandler Air Service and notified them of a 1730 arrival. The pilot received 20 gallons of fuel and performed the preflight inspection, including fuel drain and check, checking the engine oil, and verifying that the fuel in each tank was to the bottom of the tabs (30 gallons each). The pilot performed the pre-start checklist, the engine started normally, and was leaned for taxi. Prior to taxi, the pilot received the altimeter setting and winds (south-southeast at 3 knots), from the fixed base operator (FBO). The pilot taxied to runway 17 and observed a limp windsock during the taxi. He held short of runway 17, set the brakes and performed the pre-takeoff checklist. During his leaning of the mixture, the pilot set the revolutions per minute (rpm) at 1,800, leaned mixture for an increase in rpm, then richened the mixture by one full turn. Once the pilot completed his pre-takeoff checklist, he made a traffic advisory and positioned the airplane for takeoff on runway 17. He held the brakes and applied full throttle. As the rpm came up to 2,600 rpm, the engine sounded normal, the brakes were released, and he began the takeoff roll. During takeoff, a significant more ground roll was required than normal to develop airspeed. However, the pilot considered this to be expected from a 5,000 feet mean sea level (msl) airport at 70 degrees Fahrenheit. The airplane reached 65 knots approximately 2/3 down the runway and slight elevator back pressure was applied. The airplane lifted off and back pressure was eased to remain in ground effect and continue airspeed acceleration. However, the airplane did not accelerate, but instead settled back to the ground. The airplane touched down just off the end of the runway and came to a stop approximately 20 feet from an airport perimeter fence. After the pilot and passengers exited the airplane, the pilot noted that the wind had shifted to the north-northeast. The airplane sustained substantial damage when the right wing and and carry-through spars were bent. In e-mail correspondence, the pilot explained that prior to the flight, the certified flight instructor (CFI) showed him the leaning procedures for the airplane. Following a checkout flight in the airplane, the pilot advised the CFI that he had limited recent experience operating out of higher elevation airports. The CFI and pilot went over the following information: Bisbee's elevation and runway distance; leaning procedures prior to takeoff: higher ground speed during takeoff and landing; and, considerably more ground roll for takeoff. The pilot was told to lean the mixture control at runup rpm (1,800) until an increase in rpm was indicated, and then slightly richen the mixture (approximately one full turn on mixture control). The checkout was performed the day prior to the accident and done verbally rather than in the airplane. The CFI stated that he discussed the mixture leaning procedures for the airplane with the pilot. He reported that the pilot completed a check-out flight in the airplane approximately 1.5 hours in duration. Following the flight, the pilot advised the CFI that he would be flying to Bisbee the proceeding day and he wanted to review the mixture leaning procedures for the airplane. The CFI reviewed high-altitude airport takeoff procedures verbally. The procedures he explained were as follows: 1. At fields below 5,000 feet msl, the engine should be powered to 1,800 rpm and leaned until a fluctuation in the rpm was heard. The Vernier mixture control should then be turned clockwise one time. 2. At fields above 5,000 feet msl, the mixture should be leaned at full power, 75 to 100 degrees peak Exhaust Gas Temperature (EGT). The CFI noted that he told the student to lean the mixture using full power, although the field elevation was 4,780 feet msl. He further stated that he did not teach the leaning procedures outlined in the pilot's operating handbook because they were not conducive to safe flight when operating out of higher elevation airports. He preferred using the procedures that he had acquired through his mountain flying experience. AIRCRAFT INFORMATION The airplane was a Beech 35-C33 manufactured in 1967. It was equipped with a Continental IO-470K engine, rated at 225 horsepower. The engine had a total time of 5,325 hours with 1,915 hours accrued since the last overhaul. The last inspection was completed on June 16, 2005, and 65 hours had been flown on the airplane since the inspection. On October 8, 1985, the airplane was modified and a Vernier mixture control was installed. AIRPORT INFORMATION Airport information for Bisbee Municipal Airport contained in the Airport Facility Directory, Southwest, indicates that runway 17/35 is 5,929 feet in length and 60 feet wide. The estimated airport elevation is 4,780 feet msl. Using a Safety Board computer program, and the weather conditions for Bisbee Douglas International Airport, Douglas/Bisbee, the density altitude was calculated to be 6,692 feet msl. Bisbee-Douglas International is located about 15 miles northeast of Bisbee Municipal. TESTS AND RESEARCH Following the accident, local recovery personnel initially moved the airplane from the end of the runway using its own engine power. Because of this, the coloration and condition of the spark plugs immediately following the accident could not be ascertained. The engine was test-run on October 18 by the Federal Aviation Administration (FAA) coordinator using the installed propeller. The tachometer showed 2,450 rpm. The right and left magnetos showed a drop of about 50 rpm on each side. No preimpact operational or mechanical anomalies were noted. The coordinator did note that the blades on the propeller were slightly bent due to impact damage sustained in the accident. A later teardown of the engine by Arizona Air Craftsman showed that the camshaft lobes and lifters were all within the manufacturer's specified tolerances. ADDITIONAL INFORMATION In the Beech 35-C33 pilot's operating handbook (POH) Section VII, Systems Description, the pilot operating handbook for the airplane describes the best power procedures utilizing the manifold pressure and fuel flow indicator gauge. The manifold pressure and fuel flow indicator gauge are combined into one distinct gauge. The fuel flow indicator shows fuel flow in gallons per hour and is marked with a green arc to indicate normal fuel flow operating limits. The takeoff optimum fuel performance range is covered by green sectors and the high side of each green sector represents the appropriate fuel setting required to obtain maximum power when operating at full throttle, 2,600 rpm. In Section IV, Normal Procedures, the POH states in the Before Takeoff section: Throttle 1,900 RPM, Mixture- FULL RICH (or as required by field elevation). In the Take-off checklist, it states the following: Take-off Power- Full Throttle, 2,600 rpm, Power- SET TAKE-OFF POWER (Mixture- SET as required by field elevation). Using weights obtained from the pilot and information from the POH, the weight and balance was calculated by the National Transportation Safety Board investigator. The gross weight of the airplane was 3,009 pounds and the center of gravity was 82.97 using the forward positions of the seats. The POH states that the maximum gross weight for the airplane is 3,050 pounds and the forward and aft center of gravity limits are 81.5 and 86.7 inches, respectively. Assuming the mixture is leaned to the appropriate fuel flow, the approximate takeoff distance ground roll was calculated to be approximately 2,100 feet. The approximate distance to clear a 50-foot obstacle was calculated to be about 3,500 feet. According to the manufacturer of the airplane, there are no performance calculations when the mixture is not leaned in accordance with the prescribed procedures. According to FAA publication, Engine Operation for Pilots (FAA-P-8740-13), "fuel flow through either a carbureted or fuel injected inductions system must be adjusted manually, in almost all instances, to provide for the most efficient fuel to air ratio for efficient combustion within the cylinders. Given certain fuel to air mixtures, it's possible to have a situation where the engine will run rough - or will not run at all. Since air density varies with temperature and altitude, it's important to understand when and how to adjust the mixture control to obtain the best performance, fuel economy and maximum life from your engine. The Handbook for aircraft equipped with fuel flow gauges contains appropriate fuel flow settings or, alternatively, the fuel flow gauge may be marked for correct flow at each power setting. You need only lean the mixture to the published or marked fuel flow values to achieve the correct mixture."
the pilot's failure to lean the mixture in accordance with the pilot operating handbook specified procedures, which resulted in a power deficiency, a degraded climb capability, and the inability to attain/maintain an adequate airspeed that led to a stall/mush condition while departing in high density altitude conditions. The pilot's failure to abort the takeoff when an excessive takeoff ground roll became apparent was also causal. Also causal, was the certified flight instructor's failure to provide the proper leaning procedures during a preflight briefing.
Source: NTSB Aviation Accident Database
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