On July 25, 1992, a Piper PA-38-112 (registration N9240T) operated by Stramel Aviation Inc. was involved in an aviation accident near Carrollton, TX. Investigators recorded the probable cause as: Failure of the main valve for the carburetor heat box, which was sucked into the carburetor inlet, blocking airflow and rendering the carburetor inoperative; portions of the valve assembly had been failing for an unspecified time and its retaining screws had… This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 1 related events involving the same aircraft type or operator are linked below.
An airplane experienced engine failure after applying carburetor heat during descent. The pilot attempted a forced landing but struck a fence and impacted terrain. Investigation found a failed carburetor heat box valve.
Accident Sequence
The pilot was descending the airplane into the control zone and had received clearance to enter a right base for runway 15. After applying carburetor heat, the engine quit. The pilot executed a 180-degree turn and descended over an open grass field while attempting to glide to a dirt field. A fence and a railroad track lay between the fields. The airplane struck the fence, rotated approximately 180 degrees, and descended out of control, impacting the terrain near the railroad tracks.
Investigation Findings
The investigation revealed that the main valve for the carburetor heat box had failed and was sucked into the carburetor inlet, blocking air flow and rendering the carburetor inoperative. Further investigation found that portions of the valve assembly had been failing for an unspecified time prior to the accident and that its retaining screws had not been secured properly.
Probable cause
Failure of the main valve for the carburetor heat box, which was sucked into the carburetor inlet, blocking airflow and rendering the carburetor inoperative; portions of the valve assembly had been failing for an unspecified time and its retaining screws had not been secured properly.