Cargo Charter Flight Returns to Airport After Reported Engine Issue (N30MB)

Incident Overview and Initial Communications A commercial pilot was operating an on-demand cargo charter flight when, shortly after takeoff, he contacted the tower controller. The pilot stated that he wanted to “come back and land” because he was “having trouble with the left engine.” He elected to fly a left traffic pattern and return for landing. No further transmissions were received from the pilot after that communication. The accident site was located about 0.50 mile southeast of the runway’s displaced threshold. ## Flight Data and Airspeed Analysis GPS data showed that after takeoff the airplane entered a left turn to a southeasterly course and reached a maximum GPS altitude of 959 ft, about 342 ft above ground level. The aircraft then entered another left turn that appeared to continue until the final data point. The altitude associated with the final data point was 890 ft, about 273 ft above ground level. The final GPS data point was located about 135 ft northeast of the accident site. Based on the GPS data and prevailing surface winds, the airspeed during the turn was about 45 knots. According to the airplane flight manual, the stall speed in level flight with the wing flaps extended was 59 knots. ## Postaccident Examination and Findings Postaccident examination and testing of the airframe, engines, and related components did not reveal any preimpact mechanical failures or malfunctions that would have precluded normal operation. As a result, the nature of any issue related to the left engine could not be determined. Based on the evidence, the pilot failed to maintain adequate airspeed while turning the airplane back toward the airport, which resulted in an aerodynamic stall/spin.