Friday, July 29, 2016

Cessna 172E Skyhawk, N3677S: Accident occurred July 28, 2016 in Rexburg, Madison County, Idaho

National Transportation Safety Board - Aviation Accident Factual Report:

NTSB Identification: GAA16CA403
14 CFR Part 91: General Aviation
Accident occurred Thursday, July 28, 2016 in Rexburg, ID
Aircraft: CESSNA 172, registration: N3677S
Injuries: 1 Uninjured.

NTSB investigators used data provided by various entities, including, but not limited to, the Federal Aviation Administration and/or the operator and did not travel in support of this investigation to prepare this aircraft accident report.

The student pilot reported that while practicing short-field landings on runway 17, a 4,200 foot asphalt runway, he overshot his intended landing area. He reported that about 65 knots indicated air speed and 25 feet above ground level (AGL), he executed a go-around by applying mixture rich, full throttle, carburetor heat cold, but the electric flaps were left fully extended. He reported that he pulled back on the yoke, but he could not get the airplane to climb, and the airplane descended to the right side of the runway, and touched down in the safety area to the right of the runway and nosed over. The airplane sustained substantial damage to both wings, vertical stabilizer and the rudder.

The pilot reported that there were no mechanical malfunctions or anomalies with any portion of the airplane during the flight that would have prevented normal flight operations.

Photographs of the accident airplane provided by the Federal Aviation Administration (FAA) showed the airplane inverted with the flaps extended. 

The airplane manufacturer pilot operating handbook prescribed Balked Landing procedure states:

1. Throttle – Full Open

2. Carburetor Heat – Cold

3. Wing Flaps - 20 Degrees (Immediately)

4. Climb Speed – 55 Knots

5. Wing Flaps 10 Degrees (Until obstacles are cleared) Retract (after reaching a safe altitude and 60 KIAS)

The meteorological aerodrome report at accident airport about the time of the accident indicated: The temperature was 90 degrees Fahrenheit, dew point was 37 degrees Fahrenheit, the wind was out of 170 degrees true at 7 knots and varying between 140 degrees and 200 degrees true. The altimeter setting was 30.10. The field elevation at the airport was 4,858 feet and the density altitude was 7,850 feet.

According to the FAA Pamphlet 8740-2 pertaining to Density Altitude:

Whether due to high altitude, high temperature, or both, reduced air density (reported in terms of density altitude) adversely affects aerodynamic performance and decreases the engine's horsepower output. Takeoff distance, power available (in normally aspirated engines), and climb rate are all adversely affected. Landing distance is affected as well; although the indicated airspeed (IAS) remains the same, the true airspeed (TAS) increases. From the pilot's point of view, therefore, an increase in density altitude results in the following:

• Increased takeoff distance.

• Reduced rate of climb.

• Increased TAS (but same IAS) on approach and landing.

According to the aforementioned FAA Pamphlet, the Koch Chart (chart in docket) depicting the relationship between airport temperature (90 degrees) and airport pressure altitude (4,693 feet), the climb rate decreases by 64 percent. The pilot initiated the balked landing procedure at 25 feet AGL.

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