N898CPPiper PA-32-300 · 1975

On August 12, 2023, at 0913 eastern daylight time, a Piper PA-32-300, N898CP, was substantially damaged when it was involved in an accident in Haines City, Florida. The private pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

According to the pilot, this was the first flight since the engine’s spark plugs were replaced due to an uneven magneto drop. The pilot intended to perform a few maneuvers in the local area and return to land at the departure airport. The pilot stated that he performed a thorough preflight inspection and upon visual inspection, all four fuel tanks were filled to the “tabs” which he reported would be sufficient for the planned flight. After the preflight inspection, the pilot started the engine and performed an engine runup with no anomalies noted. Furthermore, he stated “the engine had never run smoother.”

The pilot taxied to the runway and departed. The pilot reported that during the climb the engine was “smooth” while operating at full power. After he cleared the Class B airspace surrounding his home airport, the pilot began a climb up to 7,500 ft mean sea level (msl). After advancing the mixture and propeller controls, the pilot noted that the engine speed immediately decreased to about 1,200 rpm. The pilot established best glide speed and attempted to regain engine power by moving the throttle forward and aft, switching fuel tanks twice and turning on the electrically-driven fuel boost pump; however, engine power did not return. The airplane continued to descend until it struck trees. During the accident sequence, the wings and fuselage sustained substantial damage. The left wing fuel system remained intact after the accident. The right wingtip fuel tank was separated from the wing during the impact sequence, and the right wing separated from the fuselage at the wing root, resulting in both fuel lines for the right wing fuel tanks being fractured.

The wreckage was recovered to an aircraft salvage facility and was examined by a Federal Aviation Administration (FAA) inspector and representatives from the airframe manufacturer. The throttle, mixture, and propeller control cables were found to be secured to their cockpit controls and their corresponding engine controls. The fuel selector valve was tested and was found to operate normally in all positions when low pressure air was supplied into each of the fuel tank outlet lines at the wing roots. The airframe fuel system was found to be clear of obstructions up to the engine-driven mechanical fuel pump inlet line. The electrically driven fuel pump was activated using the airframe’s electrical system and the electrical fuel pump operated normally. An examination of the airframe’s induction system for the engine revealed that the fuel servo inlet tube was improperly installed and was chaffing against the firewall; as a result, a large hole had worn through the induction tube, allowing unfiltered air to enter the fuel servo. After removing the induction tube, the fuel servo air inlet was found to be coated in a mixture that was consistent with engine oil, dirt, and grease. An examination of the rest of the engine did not reveal any anomalies that would have prevented normal operation of the engine.

The fuel servo was removed from the engine and sent to an overhaul facility for testing. Testing of the fuel servo revealed that, despite the contamination in the air inlet, the servo could meter the fuel/air mixture to allow normal engine operation. Further examination of the fuel servo revealed that the throttle valve idle setting was set to fully close the throttle valve. This setting would result in the throttle valve obstructing inlet air going into the engine. According to the technician at the overhaul facility, it is common for maintenance to set the idle setting to this position when there is an induction leak that is downstream of the fuel servo. The idle mixture setting was observed to be set by maintenance to near the full rich position. A gasket in the mixture control was found to be torn; however, the mixture control was still capable of normal operation during the testing. There were no further anomalies noted during the fuel servo testing and examination that would have precluded normal engine operation.

The airplane was equipped with a Garmin G500 TXi that recorded several engine parameters as well as fuel tank quantities. The recorded data revealed that at the time the engine lost engine power, the left main fuel tank contained 16.6 gallons, the No. 1 auxiliary fuel tank contained 13.6 gallons, and the No. 2 auxiliary fuel tank contained 16.5 gallons. The right main fuel tank reported 0 gallons for almost the entire flight; further review of the 2 previous recordings also showed that the right main fuel tank reported 0 gallons for most of the recorded time. The pilot stated that the right main fuel tank quantity indications had not been working since he purchased the airplane, and that his mechanic was still troubleshooting the problem. The pilot stated that since he knew the fuel quantity for the right main fuel tank was inoperative, he always would manually check the fuel level before flight.

A review of the fuel pressure, fuel flow, and EGT data revealed that just before the loss of engine power, the fuel pressure dropped from 21.7 psi to about 2.4 psi. At the same time, the fuel flow dropped from 19.47 gph to about 7.0 gph, followed by another drop to about 0.3 gph. During the fuel pressure and fuel flow drop, the EGTs initially climbed about 200° F, which would be consistent with the fuel air ratio becoming leaner. After the initial temperature climb, each of the cylinder EGT readings dropped sharply about 1,000° F, which would be consistent with combustion no longer occurring within the engine’s cylinders. Fuel pressure and the cylinder EGTs never increased after the loss of engine power; the fuel flow only increased to 0.8 gph after the loss of engine power.