Ruidoso, NM, USA
N5410D
Beech 35
The pilot and one passenger were departing from an airport located at an elevation of 6,813 ft mean sea level (msl). The pilot determined that, based on the temperature and gross weight of the airplane, the takeoff ground roll distance was about 2,900 ft total distance required to clear a 50-ft obstacle. The runway was 6,300 ft long. The pilot reported that the airplane became airborne about halfway down the runway and climbed to about 150 to 200 ft above ground level when he noticed a loss of engine power and the airplane began to descend. The pilot maneuvered the airplane for a forced landing and the airplane impacted terrain, resulting in substantial damage. A postaccident examination of the airplane revealed no mechanical malfunctions that would have precluded normal operation, and onboard video revealed that the engine continued to produce sufficient power throughout the flight. Before the accident flight, the pilot determined that, based on his calculation, the density altitude was 8,500 ft mean sea level (msl). Based on the weather conditions reported by the airport’s automated weather observation at the time of the accident, the density altitude was about 9,700 ft msl, which required a takeoff distance of about 3,300 ft. It is likely that the takeoff and climb performance, due to the density altitude, was degraded to an extent beyond that anticipated by the pilot, and the airplane was unable to maintain altitude.
On August 17, 2019, about 1255 mountain daylight time, a Beechcraft H35 airplane, N5410D, was destroyed when it was involved in an accident near Ruidoso, New Mexico. The pilot and pilot-rated passenger were seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that, the day before the accident, he flew the airplane from Texas to the accident airport with no issues. He also added that he had flown in and out of the accident airport several times before and was familiar with high density altitude operations. Before the accident flight, the pilot determined that, based on his calculation, he reported that the density altitude was 8,500 ft mean sea level (msl), and the airplane’s weight was 2,803 pounds which was about 100 pounds under gross weight and within the center of gravity envelope. The takeoff ground roll distance required about 2,900 ft to clear a 50-ft obstacle. The runway was 6,300 ft long. The pilot leaned the engine for maximum performance and determined that if the airplane did not reach takeoff speed by the 3,000-foot runway marker, he would abort the takeoff. The airplane reached rotation speed about midfield and climbed to about 150 to 200 ft above ground level (agl) when the pilot noticed a loss of engine power. The airplane began to descend, and the pilot maneuvered the airplane for a forced landing. A witness located on the west side of the airport saw the accident airplane flying unusually low (no higher than 100 ft agl) in a northerly direction over runway 30. When it reached the intersection of runway 06/24, it started to descend out of view. The witness could hear the engine, and at no time did he see any smoke or vapors. He then ran to the terminal and prepared the fire truck and drove it to the accident site. Once there, he observed that about 5 gallons of fuel had leaked out of one of the wings, which had struck a tree. The airframe was severely damaged, and the engine was detached from the airframe. The left magneto was attached, and the right magneto mount was partially damaged. The starter was detached. The carburetor was severely damaged. All cylinders remained attached to the crankcase. The top spark plugs, and cylinder rocker box covers were removed. The top spark plugs were intact and exhibited normal operational signatures. The electrode gaps were consistent with service specifications. The crankshaft was rotated by hand and rotational continuity was established throughout the engine and valve train to the accessory section. Equal movement was observed on all the intake and exhaust valve rocker arms. Thumb compression and suction was obtained on all six cylinders. The magnetos were actuated by rotating the crankshaft, and spark was observed. The intake system was severely damaged, although it remained intact at the cylinder’s heads. The air filter and filter housing were severely damaged. The exhaust system was severely damaged, although it remained intact at the cylinder heads. The engine cylinders were examined internally using a lighted borescope. The piston tops and cylinder sidewalls appeared normal. No evidence of foreign object ingestion was observed. The examination revealed no mechanical malfunction that would have precluded normal operation. An onboard GoPro camera captured the accident takeoff in two video files; the first contained audio and video of the airplane taxiing to the runway and the second contained audio and video of the takeoff and subsequent impact with terrain. Both videos showed the instrument panel. The first video showed that the tachometer gauge read 1,300 rpm and an engine total time of 1,781.74 hours. The fuel pressure indicator read 3 psi, the manifold pressure indicator read 13 inHg, and the suction gauge read 4.75 inHg. The altimeter indicated an altitude of about 6,750 ft msl, and the fuel quantity gauge indicated 51.6 gallons of fuel remaining. The second video showed that the pilot applied power and the airplane began to accelerate down the runway. The tachometer indicated 2,600 rpm, the fuel pressure indicator read 6.5 psi, the manifold pressure indicator read 22.5 inHg, and the suction gauge read 6 inHg. About 40 seconds after the airplane started to accelerate, it lifted off the runway. The pilot retracted the landing gear, and about 25 seconds after takeoff, the intersecting runway, 6/24, was visible as it passed below. About 38 seconds after liftoff, the tachometer indicated 2,400 rpm, the manifold pressure indicator read 23 inHg, and the suction gauge indicated 5.8 inHg. The landing gear indicator showed that the gear was retracted, and the propeller control lever was in the full-forward position. About a half-second later, the camera revealed that the throttle lever was in the full forward position, the mixture control lever appeared to be in line with the throttle lever and in the full forward (rich) position, and the yoke was being pulled aft. The airplane impacted terrain 40 seconds after takeoff. Based on the weather conditions reported by the airport’s automated weather observation system at 1255, the density altitude at the time of the accident was about 9,700 ft msl, which required a takeoff distance of about 3,300 ft.
The airplane’s inability to maintain altitude during the initial climb due to a degradation in the airplane’s performance as a result of high-density altitude conditions at the time of takeoff. Contributing to the accident were the pilot’s inadequate preflight performance planning calculations.
Source: NTSB Aviation Accident Database
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