N135DG – Piper Aircraft Corp PA-28R-201T – 2024-08-04 NTSB Accident Report

On August 4, 2024, about 1315 Pacific daylight time, a Piper PA-28R-201T airplane, N135DG, was substantially damaged when it was involved in an accident near Sacramento, California. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The pilot reported that he refueled the airplane before departure. He subsequently completed a preflight inspection and engine runup, verifying that the fuel selector lever was set to the right wing fuel tank. During the takeoff roll, he confirmed that he had takeoff power set to 39 inches of manifold pressure. During the initial climb, about 500 ft mean sea level, the engine sputtered, and the pilot noticed that the manifold pressure indicated about 31 inches.

The pilot initiated a 180° turn toward the airport, turned the fuel boost pump to the “high” position, and declared an emergency with the air traffic control tower. As he realized he would not be able to make it to the airport, the pilot initiated a forced landing on a nearby golf course. During the landing sequence, the airplane impacted the ground and subsequently slid into a building before it came to rest upright. Postaccident examination of the airplane revealed substantial damage to both wings.

Data recovered from the onboard engine monitor revealed that the manifold pressure and rpm were 30.5 inches of mercury (inHg) and 2,339 rpm, respectively, when the pilot returned to the airport, about 1.6 nautical miles from the departure end of the runway at an altitude of 691 ft. The last recorded data was 29.3 inHg and 148 rpm, recorded at an altitude of 60 ft about 1,280 ft from the accident site.

Examination of the airframe revealed that the sleeve connecting the air filter cover assembly to the turbocharger inlet had detached. A review of the airplane illustrated parts catalog showed that a t-bolt, flat-banded clamp, part number MS-21920-26, was required. Instead, a lined worm gear clamp was discovered around the sleeve that held it onto the inlet of the turbocharger. A t-bolt flat-banded clamp can provide consistent, 360°, leak-resistant sealing under high vibration and temperature, ideal for hose connections (see figure 1).

Figure 1. View of turbocharger, installed clamps, and required T-banded clamp overlayed over an image of the engine from the IPC.

The engine remained attached to the engine mounts and the damaged engine truss. Both propeller blades remained attached to the propeller hub and flange, which was connected to the crankshaft. The accessory case and attached accessories were unremarkable. An oil drain plug was replaced, and the turbocharger inlet sleeve was reinstalled with the two found worm gear clamps. After oil was added, the engine started using fuel drawn from a header tank that was plumbed into the fuel system and the engine was run at a constant 1,300 to 1,500 rpm for 5 minutes. Due to impact damage, the engine could not be operated at higher power settings or at idle. The throttle, mixture, and propeller controls were not operating with full travel due to impact damage to the engine mounting. After shutdown, the sleeve was again found detached from the turbocharger.

The engine logbook indicated that the most recent maintenance performed was an annual inspection completed on April 2, 2024, about four months before the accident flight. The entry for the inspection stated that the induction system was checked. On September 22, 2020, about four years before the accident, the turbocharger was reinstalled after it was repaired. The log entry did not specify whether the hardware securing the inlet sleeve was replaced. The logbook did not contain any additional references to the turbocharger between September 2020 and the accident flight.