Aviation Accident Summaries

Aviation Accident Summary WPR23LA017

Mesa, AZ, USA

Aircraft #1

N747ML

CESSNA 177RG

Analysis

The pilot conducted an hour-long local flight to break in the newly-installed engine, and was returning to the airport for landing when the engine lost all power. After a failed attempt to restart the engine, the pilot initiated a forced landing into a water canal. The airplane impacted a berm and came to rest in the canal, resulting in substantial damage to the left wing and engine mount. About one cup of fuel was recovered from each fuel tank during recovery from the accident site. Examination of the engine revealed that the fuel line from the fuel injection servo to the flow divider, which connected at the baffle union fitting on the aft side of the firewall, leaked when the engine-driven fuel pump actuated during the manual rotation of the propeller. The B-nut fitting could be tightened a half revolution until it seated onto the fitting by hand. There was no physical damage to the fitting, nor any accident-related impact damage within the surrounding area of the fitting. Review of the task cards for the engine installation provided by the repair station indicated that the installation was completed and signed off by both a technician and inspector. Based on the available information, it is likely that the B-nut was not properly torqued onto the baffle union fitting and that, during the accident flight, the B-nut loosened, resulting in a fuel leak, fuel exhaustion, and a total loss of engine power.

Factual Information

On October 18, 2022, about 0740 Pacific daylight time, a Cessna 177RG, N747ML, was substantially damaged when it was involved in an accident near Mesa, Arizona. The pilot sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated that Falcon Aviation Services, based out of Falcon Field Airport (FFZ), Mesa, Arizona, reinstalled the overhauled engine and signed off the engine logbook entry on October 12, 2022. After multiple ground runs, the pilot completed an uneventful post-overhaul flight. The pilot reported that he departed on the accident flight about 0624 with 28 gallons of fuel onboard and maneuvered north of FFZ, where he flew about one hour orbiting about 4,000 ft above the ground at 65% to 75% engine power. The pilot returned to FFZ and was turning the airplane from base to final for runway 04R when the engine lost total power. The pilot attempted to restart the engine but was unsuccessful, and he conducted a forced landing into a water canal. The airplane impacted a berm and came to rest in the canal, resulting in substantial damage to the left wing, fuselage, and engine mount. (See figure 1.) During the recovery of the airplane, about one cup of fuel was recovered from each fuel tank. Figure 1. Google map view of wreckage location in relation to FFZ Runway 04R, with embedded picture of accident airplane in water canal. Postaccident examination of the airframe and engine revealed that the fuel supply line from the fuel injection servo to the fuel flow divider, which attached to the baffle union fitting, exhibited a surging fuel leak when the propeller was manually rotated. Fuel continued to surge from the fuel line fitting as the engine-driven fuel pump actuated with the continuous manual rotation of the propeller. It was determined that the fuel line B-nut (figure 2) was not secured and was able to be turned ½ revolution to “finger tight.” The fuel pump, fuel flow divider, and each corresponding fuel line was secured to its respective mounting pad or fuel system component. Figure 2. View of fuel supply line from fuel servo with overlayed close-up view of baffle union fitting connection (photo courtesy of engine manufacturer) According to the repair station, there were two primary installers of the accident engine, a technician and an inspector. The recovered task card for the engine installation revealed that the fuel system tasks, including a fuel leak check, were completed and signed off by both the technician and the inspector; however, it could not be determined which individual secured the fuel line to the baffle union fitting.

Probable Cause and Findings

The failure of maintenance personnel to properly secure the fuel supply line to the fuel flow divider, which resulted in a fuel leak, fuel exhaustion, and a total loss of engine power.

 

Source: NTSB Aviation Accident Database

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