LEADVILLE, CO, USA
N9431D
Cessna 172RG
Before takeoff from a high altitude (9,927 feet above msl, 12,400 feet density altitude) airport on a mountain flying training flight, the CFI noted that the airport elevation was higher than the takeoff data charts provided for. During takeoff, the aircraft was rotated and settled back to the ground three times during takeoff roll. On the fourth rotation, which was at the departure end of the runway, the aircraft became airborne and descended down the side of an incline where it struck a power line and came to rest in a flat rocky area. All three occupants exited the aircraft with injuries. The investigation provided information that the airport elevation was above the highest altitude provided on the takeoff data charts, the mixture was not leaned in accordance with the procedures in the manual, and the flaps were not set in the proper setting for the type of takeoff being conducted. In addition, the investigation provided information that the flight instructor had received no formal mountain flying training, that there are no FAA approved mountain flying training courses, and to act as an instructor in mountain flying no specialized training is required.
On June 6, 1996, at 1220 mountain daylight time, a Cessna 172RG, N9431D, struck power lines and then impacted terrain during initial climb following takeoff from runway 34, Lake County Airport, Leadville, Colorado. The certified flight instructor, sstudent pilot, and passenger received serious injuries and the aircraft sustained substantial damage. The aircraft was being operated under Title 14 CFR Part 91 as an instructional flight and a VFR flight plan was filed. The flight departed Centennial Airport, Englewood, Colorado, about 1050. According to the flight instructor, the flight to Leadville from Centennial Airport was uneventful with the exception that the student attempted to put in excessive nose up trim prior to takeoff. His student was flying the aircraft from the left front seat while he provided instruction in mountain flying and occupied the right front seat. The student's sister, a non pilot, was occupying one of the rear seats. They arrived at Leadville at 1155 and landed on runway 34. The instructor said they parked the aircraft, walked around for awhile and then departed about 1210. They did not take on any fuel and he estimated they had about 40 gallons (240 pounds) of fuel on board for departure and return to Centennial Airport. He said he checked performance and noted that the manual stops at 8,000 feet pressure altitude. He did note that by his calculations the density altitude was approximately 12,000 feet. Takeoff was on runway 34 following a normal run up. The flight instructor said he leaned the engine at 1,800 rpm (revolutions per minute) by using the rpm increase method and egt (exhaust gas temperature) gauge cross check. A short field takeoff was conducted using ten degrees flaps and rotating at 55 knots. According to the flight instructor, the aircraft "popped" off the ground in a nose high attitude but the airspeed was "right around flying speed." By his account, the nose was leveled and the aircraft settled and came off the ground again in a nose high attitude. He said he told the student to "get into ground affect" and then realized that they would be unable to stop on the remaining runway so he took control of the aircraft and headed towards an open area. When he took control of the aircraft, he found there was excessive nose up trim set. Some power lines were in the flight path so he said he put down all the flaps to get over the power lines. The aircraft struck the power lines with the right outer wing and the flight instructor raised the flaps and put the gear handle down. The aircraft struck the ground in a flat rocky area before the gear became fully extended and slid to a stop. All three occupants exited the aircraft, which had sustained substantial damage. All three occupants received some injuries and were transported to the local hospital. The pilot was treated and released, the passenger had surgery performed, and the student was transported to Denver, Colorado, for further treatment. According to a statement provided by the airport manager, which is included as part of the sheriff's report, about 1220, the aircraft took off on runway 34 with winds approximately 300 degrees magnetic heading at 10 knots and a temperature of 61 degrees Fahrenheit. The aircraft rotated and became airborne just past the mid point of the runway. It settled back to the ground and took off again before taxiway 'C'. It settled back to the ground nearly abeam the office, rotated again nearly abeam taxiway 'D' and rotated one more time from the numbers 16 at the runway end. It then disappeared down into a gulch. The airport manager said she dialed 911 then saw the left wing "only" come up in a hard right turn and disappear towards "Stringtown." She said the electric power at the airport went out moments after the wing disappeared while she was talking to the 911 operator. Using the weather information supplied by the airport manager, density altitude at the time was calculated to be 12,400 feet. Based on the airport manager's statement, the first rotation was approximately 3,200 feet after the beginning of the takeoff roll, the second rotation was approximately 4,000 feet down the runway with a touchdown at 4,800 feet, another rotation at 5,160 feet and the final rotation at the end of the runway which is 6,400 feet long. See attached diagram. Weight and balance was calculated based on input from the pilot and available records. At takeoff from Leadville, the aircraft weight was calculated to be 2,346 pounds and the center of gravity moment (lb.-ins./1000) was 95.7. A weight and balance work sheet and graphs are attached. A review of takeoff performance data in the operating manual provided information that none of the takeoff data charts provide information for takeoff above 8,000 feet pressure altitude. The altitude at Leadville is 9,927 feet above mean sea level (msl). Thus, takeoff ground roll and obstacle clearance performance can not be calculated. (Copies attached). According to the attached procedures from the aircraft operating manual, leaning on this aircraft should be done during a full power static run up by leaning to obtain maximum rpm. Also, both normal and short field takeoff should be done at zero flaps. The manual does provide the option of using 10 degrees of flaps at weights less than 2,550 pounds for minimum ground roll or takeoff from soft or rough fields. According to the attached performance chart supplied by Cessna, at 12,000 feet density altitude at 2650 pounds gross weight clean, with the mixture full rich, the rate of climb should be 200 fpm (feet per minute). With the mixture properly leaned, the rate of climb should be 300 fpm. With landing gear and/or any flaps, the performance capability would be decreased due to additional drag. No charts are available to calculate actual aircraft performance capability given the configuration and leaning used during the event. On June 12, 1996, the engine was examined and test run at the facilities of Beegles Aircraft Services, Greeley, Colorado. Present for the examination, in addition to the Safety Board Investigator In Charge, was a representative from Cessna Aircraft, a representative from Lycoming engines, a technician from Beegles, and the FAA. Examination of the engine provided evidence that the engine remained attached and except for the lower mounts which were bent, the number one and three exhaust stacks at the cross over which were crushed, and the propeller was twisted, bent aft, and scarred, the engine was undamaged. The engine and components were identified as follows: Engine data plate - O360-F1A6 Case serial number - L-30637-36A, match numbers 2123 Magnetos - Slick left 4251, S/N 3110611 right 4271, S/N 89010116 Carburetor - Marvel Schebler HA-6, P/N 10-5253, S/N DL-5-1356 Vacuum pump - Airborne 211CC, S/N 22T 012 Spark plugs - Champion REM-40E, except #1 and 4 bottom, REM-38E Propeller - McCauley, P/N B2D34C 220-B, S/N 83372 The condition of the engine allowed it to be test run. The test run was done with the engine mounted on the airframe. A serviceable propeller of the same model, and the right wing, for a fuel source, were installed as was a patch on the exhaust system. Using the aircraft battery the engine was started in a routine manner and idled smoothly. The engine accelerated smoothly to 1,500 rpm and magneto checks were accomplished with a 100 rpm drop on each magneto. Power was increased to 2,000 rpm and magneto checks were again done with a 100 rpm drop on each. With the engine at 2,000 rpm, the mixture was leaned in a normal fashion. Further acceleration of the engine was not attempted due to the bent engine mounts. From the 2,000 rpm setting the throttle was decreased to idle and advanced back to 2,000 rpm several times. Acceleration and deceleration were smooth, and the engine idled smoothly at 600 rpm. The engine was shut down with the mixture. During the engine run, all engine gauges remained in the normal operating range. The flight instructor said he had been to Leadville on previous occasions with a loaded Cessna 172 aircraft and felt he was experienced in mountain flying. For details of the flight instructor's experience, refer to page 3 of this document. During the investigation, no information was found that the flight instructor had been through any formal mountain flying training and no information was found that there are any FAA approved mountain flying training courses available. According to the FAA, by holding a flight instructor certificate, a flight instructor is considered to be qualified to instruct in mountain flying and no specialized training is required. A review of FAA records provided no information that the student held a private pilot certificate, as shown in the pilot operator report, other than a student certificate with a second class medical dated November 7, 1994. Her records did indicate a previous first class medical dated June 24, 1980. Available records provided information that the student had 308 hours of flight time and the last two types of aircraft she flew prior to the accident flight were the BN2A-26 Islander for 1.0 hours on May 21, 1996, and the PA-23-250 for 1.0 hours on May 27, 1996. Both flights occurred in Florida. Her other flight experience is unknown.
Inadequate preflight planning and preparation and failure to follow aircraft operating procedures and directives. Factors were high density altitude, inadequate training of the flight instructor and insufficient standards and requirements for flight instructor training in mountain flying.
Source: NTSB Aviation Accident Database
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