NTSB Factual Report

On July 3, 2014, about 1100 central daylight time, a Piper PA-24-250, N5923P, was substantially damaged during an aborted landing at Monroe County Airport (MVC), Monroeville, Alabama. The flight instructor and a pilot rated passenger sustained minor injuries. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed for the personal flight, which was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. The flight originated from Shelby County Airport (EET) Alabaster, Alabama at 1000.

According to a written statement by the flight instructor, he performed three landings at EET to obtain currency and subsequently departed for MVC with another pilot onboard. After arriving at MVC, the instructor configured the airplane for an RNAV/GPS approach to runway 03. About 100 feet (ft) above ground level (agl), the instructor initiated a go-around and retracted the landing gear and flaps. When the airplane reached about 400 ft agl the engine "sputtered, went quiet, came back on briefly, and then went quiet again." The instructor then switched fuel tanks and verified that the fuel boost pump was on. He also observed that the fuel mixture was set to rich and both magnetos were on. The instructor established best glide speed and selected a field to his right to conduct a forced landing. During the landing, the airplane impacted a tree, the left wing separated, and the airplane came to rest inverted, resulting in substantial damage to both wings and the fuselage.

A witness stated that the airplane engine started "sputtering" as it climbed away from the runway at an altitude of about 100 ft about 800 ft from the departure end of runway 03. The airplane then entered a level flight attitude and the sputtering ceased. The witness heard the engine functioning, but not at full power. The airplane climbed about 100 ft, began a right turn, and eventually started to descend until no longer in view.

During a follow-up interview, the instructor stated that the purpose of the flight was to familiarize the pilot-rated passenger with the operation of the newly-installed global positioning system (GPS). Prior to the flight, the instructor visually inspected both wing tanks and estimated that each contained about 30 gallons of fuel. After starting the engine, the airplane sat at an idle power setting for about 30 minutes while the pilots configured the GPS prior to departure. They then completed three takeoffs and landings at EET prior to departing for MVC. The airplane was flown for a total of 1 hour and 20 minutes with the fuel selector on the left tank. The instructor also noted that he did not apply carburetor heat at any time following the loss of engine power.

Examination of the airplane and engine by a Federal Aviation Administration inspector (FAA) did not reveal any mechanical malfunctions which would have resulted in a loss of engine power. The crankshaft was rotated by hand at the propeller, and continuity was established through the powertrain to the valvetrain and the accessory section. Compression was confirmed on all cylinders, and the magnetos produced spark at all terminal leads. Fuel line continuity was tested from the bladder tanks to the carburetor and was absent of contamination. The fuel strainer was void of debris and the carburetor screen contained minor debris, but was not plugged. The carburetor had separated from the engine during the impact sequence; the floats were normal and there were no restrictions inside the needle and seat. There were some rust and debris particles in the bottom of the carburetor fuel bowl, which likely accumulated during postaccident storage of the wreckage. When the fuel boost pumps were connected to a 12 volt battery, both pumps produced suction at their respective inlets.

A weather observation taken at Middleton Field Airport (GZH), Evergreen, Alabama, located 16 nautical miles east of the accident site, about the time of the accident reported wind from 350 degrees at 3 knots; visibility 10 statute miles; sky clear; temperature 27 degrees C, dewpoint 22 degrees C; altimeter 30.08 inches of mercury.

According to the manufacturer's pilot's operating handbook, at a cruise altitude of 6,000 feet, under standard atmospheric conditions, and at about 2,200 rpm, the airplane's estimated fuel consumption was approximately 14 gallons per hour. Based on these values, the engine burned a total of about 22.4 gallons of fuel during 1 hour and 36 minutes of flight time.

Review of an FAA carburetor icing envelope chart revealed a potential for serious icing at descent power given the atmospheric conditions present at the time of the accident.

NTSB Probable Cause

A loss of engine power for reasons that could not be determined because postaccident examination of the engine and fuel system revealed no anomalies.