NTSB Factual Report

HISTORY OF FLIGHT

On August 8, 2015, about 1652 central daylight time, a Cessna 172G, N5800R, sustained substantial damage when it impacted a field after a partial loss of power during the initial climb from a private airstrip near Hartington, Nebraska. The pilot and one passenger received serious injuries. The airplane was registered to and operated by the pilot under the provisions of the 14 Code of Federal Regulations Part 91 as personal flight. Visual meteorological conditions prevailed at the time of the accident and no flight plan was filed. The flight departed from a private grass airstrip about 1650, and was en route to the Hartington Municipal Airport (0B4), Hartington, Nebraska.

The pilot reported that the airplane had undergone an annual maintenance inspection at an aviation maintenance facility located at 0B4. The first flight after the completion of the maintenance inspection was on the day of the accident. The pilot reported that he completed the preflight inspection, departed 0B4, and flew to the Chan Gurney Municipal Airport (YKN), Yankton, South Dakota, where he performed one touch and go landing. He then flew to the private airstrip where he did a full stop landing. About 15 minutes later, the pilot departed on the southwest runway that was about 1,750 ft long by 30 ft wide. The alfalfa that covered the runway was cut to about 2.5 inches in height.

In his written statement, the pilot reported that he initiated the takeoff with the flaps set at 30 degrees (However, in phone interviews, he stated he used full flaps, 40-degrees, for takeoff). The airplane became airborne about 1/2 to 2/3 down the runway. About 50 feet above ground level (agl), as he reached over to raise the flaps 10 degrees, the engine lost partial power. He reported that the yoke abruptly came back toward him, the nose shot up, and the stall warning horn sounded. He pushed the yoke forward as hard as he could with both hands, and trimmed the nose wheel down, but the trim wheel was hard to turn, almost requiring two hands to move it. He reached over to the flap handle and "bumped" it to 10 degrees. The left wing dropped and the airplane impacted the ground.

A witness, who owned the private airstrip, reported that he was standing at the end of the field watching the airplane as it departed. He reported that the airplane became airborne about 1,000 ft down the runway. He stated that the airplane was in the right pitch for climb, but it wasn't climbing, reaching about 20 ft agl over the runway. It cleared the "hump" in the road and continued to the southwest were the terrain sloped lower. He stated that the engine sounded like it was at cruising speed. He reported that the airplane kept the same pitch for 5 – 10 seconds, and then the nose went up, the left wing dropped, and the airplane went straight down.

Another witness observed the airplane flying north to south on the west side of a small hill. The airplane's altitude was about 80 ft agl. He reported that there were power lines that were about 100 ft high running east and west along the gravel road and in the flight path of the airplane. He reported that the airplane "nosed up to climb" but did not have enough power. He stated that the airplane's "nose went up, turned left, and then nosed in." In his statement to the Cedar County Sheriff's Department, the witness stated that the "plane sounded like it was losing power." He also stated, "When EMT was assessing the pilot, the pilot told them the plane lost power."

PERSONNEL INFORMATION

The 64-year-old pilot held a private pilot certificate with single-engine land rating. He had about 250 hours of total flight time, with 148 hours in make and model. He had flown 2.5 hours in the last 90 days and had received his biennial flight review on May 21, 2015. The pilot's flight logbook indicated that prior to May 2015, the last flight that he logged was on July 18, 2004. He held a third class medical certificate that was issued in April 2015.

AIRCRAFT INFORMATION

The airplane was a single-engine Cessna 172G manufactured in 1966. It seated four and had a 2,300 lb maximum gross weight. It was powered by a 145-horsepower Continental O-300-D engine. The pilot purchased the airplane in May 2015. An annual maintenance inspection had been completed on May 10, 2015, with a total time of 4,996.8 hours. According to the pilot, he flew the airplane one flight after the annual inspection had been completed and determined that the engine was not operating properly. The pilot decided to have another annual maintenance inspection performed. That annual maintenance inspection was performed on July 2, 2015, with a total time of 4,990 hours. The engine logbook entry dated 7-2-15 indicated that all six cylinders were serviced with new rings, seals, and gaskets. A cylinder compression check was accomplished, and a ground and flight check was performed.

Examination of the aircraft logbooks revealed that the airplane had flown 1 – 3 hours between annual maintenance inspections for the last 10 years. The total time on the engine was 5,002.9 hours and the time since major overhaul (TSMOH) was 1,615.9 hours. The Continental Motors Aircraft Service Information Letter SIL-98-9C's recommended time between overhaul periods for the O-300-D engine is 1,800 hours or 12 years.

METEOROLOGICAL INFORMATION

At 1655, the surface weather observation at YKN, located about 8 nm north of the accident site, was: wind 120 degrees at 5 kts; sky clear; 10 miles visibility; temperature 27 degrees C; dew point 21 degrees C; altimeter 29.84 inches of mercury.

WRECKAGE AND IMPACT INFORMATION

The airplane impacted a corn field about 912 ft from the end of the private airstrip. The airplane was found nose down with the engine compartment crushed and buckled aft and upward. The wings and empennage remained attached to the fuselage. The left wing exhibited aft crushing along its leading edge, and the outboard section of the wing was buckled and twisted upward and aft. About 4 ft of the right wing's outboard section exhibited aft crushing of the leading edge. All flight controls remained attached to the airplane. Flight control cable continuity was confirmed from the cockpit to all flight control surfaces.

The wreckage was removed from the accident site and transported to a hangar for further inspection. The examination of the wreckage revealed that the flap actuator was found in the 10-degrees position. The elevator trim actuator was measured and found to be in the 5-degrees tab up position (nose down trim). The fuel selector handle was found in the BOTH position. The fuel strainer screen and bowl were clean. Fuel was found in the fuel strainer at the fire wall. The fuel caps remained attached to both wing tanks and the cap seals were pliable.

The engine was taken to an aircraft engine overhaul facility for a teardown examination. The engine was rotated. All 6 cylinders produced compression and exhibited drive train continuity. The crankshaft, camshaft, valve tappets, push rods, rocker arms, and valves exhibited no anomalies. The engine timing was checked and verified as correct. Both magnetos were bench tested and no anomalies were noted. The spark plugs exhibited no anomalies. The carburetor inspection revealed a small amount of fuel was present and the fuel screen was clean. Examination of the carburetor revealed no anomalies. The air induction system was free and clear of any obstructions. The alternator, starter, and vacuum pump were checked and no anomalies were noted. Approximately 1 – 2 inches of oil sludge was found in the bottom of the engine case, but no abnormal foreign material or debris was found.

Visual examination of the propeller revealed "S" bending of the propeller blades. The leading edges of the blades exhibited polishing and there was chordwise scratching found across the propeller blades.

ADDITIONAL INFORMATION

The 1966 Cessna 172 Owner's Manual states the following concerning wing flap settings:

"Normal and obstacle clearance take-offs are performed with wing flaps up. The use of 10-degrees of flaps will shorten the ground run approximately 10 percent, but this advantage is lost in the climb to a 50-foot obstacle. Therefore, the use of 10-degrees of flaps is reserved for minimum ground runs or for take-off from soft or rough fields with no obstacles ahead.

If 10-degrees of flaps are used in ground runs, it is preferable to leave them extended rather that retract them in the climb to the obstacle. The exception to this rule would be in a high-altitude take-off in hot weather where climb would be marginal with flaps 10-degrees.

Flap settings of 30- to 40-degrees are not recommended at any time for take-off."

The Federal Aviation Administration's (FAA) "Airplane Flying Handbook" FAA-H-8083-3A states the following about Ground Effect on Takeoff:

"Ground effect is a condition of improved performance encountered when the airplane is operating very close to the ground. Ground effect can be detected and measured up to an altitude equal to one wingspan above the surface…. As the airplane lifts off and climbs out of the ground effect area, however, the following will occur.

- The airplane will require an increase in angle of attack to maintain the same lift coefficient.

- The airplane will experience an increase in induced drag and thrust required.

- The airplane will experience a pitch-up tendency and will require less elevator travel because of an increase in downwash at the horizontal tail.

As the airplane rises out of ground effect with an insufficient airspeed, initial climb performance may prove to be marginal because of the increased drag…. The point to remember is that additional power is required to compensate for increases in drag that occur as an airplane leaves ground effect. But during an initial climb, the engine is already developing maximum power. The only alternative is to lower pitch attitude to gain additional airspeed, which will result in inevitable altitude loss."

NTSB Probable Cause

The pilot’s decision to use an excessive, unapproved flap setting for takeoff, which significantly increased the induced drag and resulted in an aerodynamic stall when the airplane flew out of ground effect.