PIPER PA-34-220T

Full Narrative

On July 24, 2024, about 1552 mountain daylight time, a Piper PA-34-220T airplane, N134MG, was substantially damaged when it was involved in an accident near Roy, Utah. The flight instructor was seriously injured and the pilot receiving instruction sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight.
According to the flight instructor, they had departed from Ogden-Hinckley Airport (OGD), Ogden, Utah, to practice single-engine maneuvers in the local practice area. They completed the maneuvers without incident, then returned to the airport and performed a practice instrument approach to runway 3, followed by a missed approach. The flight instructor and pilot receiving instruction then executed a second practice instrument approach with a simulated left engine failure. At the final approach fix, they lowered the landing gear; however, the right main landing gear indicator did not show that the landing gear was down and locked. They attempted to troubleshoot the right landing gear, including swapping the light bulbs, cycling the landing gear, and using the emergency extension, but were not successful.
They performed a low approach over runway 3, and the airport traffic control tower controller reported that the landing gear appeared to be down. The flight instructor stated that the controller offered to call fire and rescue equipment to be in position near the runway in case the landing gear collapsed on landing. The flight instructor agreed and then circled to the east of the airport while they awaited the arrival of fire personnel.
After maneuvering near the runway, they extended the upwind leg by an additional two miles before turning left crosswind. During the crosswind turn, the pilot receiving instruction advanced the power to the left engine, and the flight instructor secured the right engine to avoid damage to the propeller and engine if the right main landing gear collapsed upon landing.
The flight instructor reported that initially the airplane was able to maintain altitude and 92 kts indicated airspeed, which was best rate of climb for single-engine operation, with maximum power on the left engine. Once established on downwind, the “over-boost” light illuminated on the annunciator panel, consistent with the operating engine exceeding the manifold pressure limit of 40.5 inches of mercury. The flight instructor told the pilot receiving instruction to retard the throttle to not over-boost the left engine, but he observed that small throttle movements resulted in a decrease in manifold pressure to 23–25 inches of mercury.
As the airplane passed midfield, the instructor noticed that the airplane was unable to maintain altitude and began the steps to restart the right engine; however, he aborted the restart attempt after deciding that he needed to focus on landing. Due to their altitude and airspeed, they told the controller that they were going to land immediately south of the runway. The flight instructor took control of the airplane and maneuvered to land on a road. During the landing process, the airplane struck multiple trees and impacted a road before it came to rest upright against a tree in the front yard of a residence.
The pilot’s operating handbook stated, “the ‘over boost’ indicator lights on the annunciator panel will illuminate about 39.8 in. Hg. manifold pressure. Do not exceed 40 in. Hg. manifold pressure.” The handbook further stated, “Performance information derived by extrapolation beyond the limits shown on the charts should not be used for flight planning purposes.” Single-engine climb performance could not be calculated due to the weather conditions (pressure altitude and temperature) being outside of the range of the “Takeoff Climb Performance – Gear Retracted - Single-Engine – 4,300 lb” performance chart.
Postaccident examination of the airplane revealed that the left engine had been separated from the engine nacelle during recovery, which precluded verification of the throttle rigging. The propeller and throttle controls moved freely by hand. Full travel of the mixture cable could not be accomplished due to impact damage; partial movement was obtained. Rotational continuity was established throughout the engine and valvetrain when the propeller was rotated by hand. All ignition leads produced spark. The turbocharger was not damaged and rotated freely with no axial or radial play. The wastegate was damaged by impact forces but moved when actuated by hand, and it was connected to its supply lines. The turbo pressure relief valve moved when manually actuated with a tool by investigators.
Damage to the airframe prevented functional testing of the landing gear system.