WPR25LA092

During a local training flight, the flight instructor directed the student pilot to return to the airport to practice touch-and-go landings. After entering the traffic pattern and completing the landing checklist while turning from base to final approach, the engine sustained a total loss of power about 400 ft above ground level. The instructor assumed control of the airplane and performed the engine restart procedures; however, the attempts were unsuccessful. Realizing the airplane could not reach the runway, the instructor executed a forced landing in an open field. During the landing rollout, the nose gear dug into the soft terrain and the airplane nosed over, resulting in substantial damage to the fuselage, vertical stabilizer, and rudder. A postaccident examination of the airframe and engine revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. A portable fuel tank was subsequently plumbed to each of the fuel tank ports on the selector valve and the engine operated normally in each of the fuel selector valve positions. The carburetor heat door also moved appropriately with cabin control actuation. A review of weather data indicated atmospheric conditions conducive to the formation of serious carburetor icing at cruise-power settings. The flight instructor could not recall the position of the carburetor heat at the time of the event. Given the absence of mechanical anomalies identified during the postaccident examination, carburetor ice likely accumulated while the airplane was maneuvering in the traffic pattern before landing, resulting in the eventual loss of engine power.

On February 9, 2025, about 1115 Pacific standard time, a Piper PA-28-235 airplane, N8535N, was substantially damaged when it was involved in an accident near Shafter, California. The student and flight instructor were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The student pilot reported that while on final approach to runway 30 at Shafter Airport-Minter Field (MIT), Shafter, California, the engine had a total loss of power about 400 ft above ground level. The flight instructor took control of the airplane, performed the power-loss-in-flight checklist, and attempted to restart the engine, but was unsuccessful. The flight instructor initiated a forced landing to a plowed garlic field about 1 mile south of the runway. During the landing roll, the airplane nosed over, which resulted in substantial damage to the left wing, vertical stabilizer, and rudder. Neither the student pilot or flight instructor reported using carburetor heat during the approach to landing. Examination of the airframe and engine following the accident revealed no preimpact mechanical malfunctions or failures that would have prevented normal operation. At 1045, the weather reported at Meadows Field Airport (BFL), about 9 miles southeast of the accident site, included a temperature of 52° F and a dew point of 41° F. The calculated relative humidity at this temperature and dewpoint was about 70 percent. Review of the icing probability chart within FAA Special Airworthiness Information Bulletin CE-09-35 revealed the atmospheric conditions at the time of the accident were "conducive to serious icing at cruise power." FAA Advisory Circular (AC) 20-113, Pilot Precautions and Procedures to be taken in Preventing Aircraft Reciprocating Engine Induction System and Fuel System Icing Problems, Prevention Procedures 7 a. (12), states that prior to a prolonged descent at reduced power, carburetor heat should be applied briefly to warm the induction system. During the descent, engine power should be increased periodically to verify that normal power can be restored if needed. Pilots should also be prepared to discontinue the use of carburetor heat once power has been regained, such as when leveling off or executing a go-around after an aborted approach. Section 7 a. (13) further states that pilots should recognize that induction system icing, particularly in engines equipped with float-type carburetors, can occur even when ambient temperatures are as high as 100°F and relative humidity is as low as 50 percent. However, icing is most common when temperatures are below 70°F and relative humidity exceeds 80 percent. The probability of icing increases as temperatures approach 32°F and as humidity levels rise. The recovery crew reported that very little fuel had drained from either fuel tank while the airplane was inverted at the accident site. The fuel selector valve was found positioned to the left wingtip tank. The primerplunger was found fully seated and locked. The carburetor heat control was in the On position. The flight instructor could not recall the position of the carburetor heat at the time of the event. Examination of the cockpit engine controls, including the throttle, mixture, propeller, and carburetor heat controls, revealed full and unobstructed travel. Corresponding movement was observed at the carburetor throttle and mixture arms, as well as at the propeller governor. Operation of the fuel selector handle was normal and produced the expected movement of the selector valve, with positive detents noted at each position. The fuel selector sump drain was actuated, and approximately one-quarter cup of clear blue liquid was collected. Testing with water-detection paste revealed no evidence of water contamination. The fuel strainer bowl was intact and was removed to facilitate examination of the filter screens. The screens were free of obstruction. The strainer screen and bowl were subsequently reinstalled in preparation for an engine test run. The electric boost pump operated normally when activated from the cockpit switch. The boost pump fuel filter was removed and found visually intact and free of damage. A portable fuel tank was connected to each selector valve fuel port, and the airplane and engine were secured to a run stand. The engine successfully started using the external fuel source and demonstrated normal operation throughout the tested power range. The engine ran smoothly during the operational check in all fuel selector positions with no abnormal indications. At the time of the examination, the airplane tachometer indicated 1,288.6 hours. Maintenance records showed that the airplane had accumulated 13 flight hours since its most recent inspection on August 2, 2024.