WPR23LA197

A fuel leak caused by an age-degraded fuel pressure sender hose, which resulted in fuel starvation and a loss of engine power. Contributing to the accident was inadequate maintenance.

The pilot reported the airplane lost engine power during cruise flight following a loss of fuel pressure. The pilot was not able to restart the engine by following the emergency procedures; however, he was able to regain partial power in short bursts by engaging the auxiliary fuel pump. He diverted the airplane for landing, but landed short of the runway after the engine lost all power. The right wing and tailcone were substantially damaged during the landing. Although the engine appeared functional, it had a history of water entering the fuel system, and there was evidence of water ingestion and corrosion within those engine components. Additionally, the hose that connected the fuel pressure sender to the fuel controller had broken at the fuel controller fitting. Such a failure in flight would have resulted in the loss of fuel pressure observed by the pilot and a leak in the fuel system that would have caused the engine to lose power. No other anomalies were found with the engine or airframe fuel supply system. The hose was age-degraded, had become hard and brittle, and appeared to have corroded at the fuel controller fitting. The engine and fuel control system did not appear to have been overhauled or replaced in 28 years. Although the manufacturer recommends an overhaul be accomplished every 12 years, there is no requirement under Part 91 operations that the operator abide by the manufacturer’s engine overhaul limits.

On May 20, 2023, about 0900 Pacific daylight time, a Cessna 210, N9433T, was substantially damaged when it was involved in an accident in Redding, California. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The planned route of flight was from Salem, Oregon (SLE), to Willows, California (WLW). The pilot reported that while overflying Redding Regional Airport (RDD) at an altitude of 7,500 ft mean sea level (msl), the engine lost power. He followed the emergency engine restart procedures and noticed that the fuel pressure was zero. The engine would not restart, and the propeller was still spinning, but the pilot was able to get a surge of power by cycling the auxiliary fuel pump. He was already talking with air traffic controllers at Oakland Center and decided to turn back to land at RDD. The pilot stated that he did not initially declare an emergency because he had sufficient altitude remaining to land, and that by the time the airplane had reached a 5-mile final for runway 34 he was at 4,500 ft msl (about 4,000 ft above ground level). However, a short time later he declared an emergency with the RDD tower controllers when it became apparent that the airplane would not make the airport. He cycled the fuel pump one more time, but the engine did not respond, and the propeller stopped. The pilot decided to keep the landing gear retracted and landed the airplane in a field about ¾ mile short of the runway threshold. The airplane sustained substantial damage to the tailcone, which had separated aft of the rear cabin bulkhead. Both wings remained attached, and the right wing was bent up at the wing strut attach point. Each wing tank contained in excess of 20 gallons of fuel when examined at the accident site, and there was no evidence of fuel leak. Examination of the fuel supply system within the airframe did not reveal any anomalies that would have precluded normal operation. The engine remained partially attached to the firewall and was essentially undamaged during the accident. There was no evidence of catastrophic internal engine failure, nor was there any indication of an oil leak. The ignition system was functional, and the spark plugs all exhibited normal wear signatures and deposits, and all internal cylinder combustion surfaces exhibited similar deposits consistent with normal operation. The crankshaft could be turned by hand utilizing the propeller, and compression was noted on all cylinders. Mechanical continuity was established throughout the rotating group, valvetrain, and accessory section. All fuel and oil supply hoses remained attached at their respective fittings. However, most were hard and inflexible. The metered-side fuel pressure sender hose had broken away from the fuel controller. The hose was made of rubber and had limited flexibility; it was not covered with a fire sleeve. There were white oxidization-like deposits at the break in the fitting, and the rubber remnants of the hose were brittle and could be easily broken off with a fingernail (see figure 1). Figure 1 - Fuel pressure sender hose separation point at fitting. The entire engine fuel control system was disassembled and examined. Although all components appeared to be functional, they also exhibited evidence of water ingestion and corrosion. Review of airworthiness records indicated that the airplane’s previous owner replaced the fuel caps and fuel tank inlets in June 2017. The airplane’s current owner reported that early on in his ownership of the airplane he was routinely draining water out of the fuel system during preflight inspections, and that it was his understanding that the airplane had sat unused for long periods before his purchase. The only maintenance records available were from the accident period back to 2017, and during that time the fuel pressure sender hose was not replaced. Evidence suggested that both the engine and its fuel control components were last overhauled about 28 years before the accident in 1995. Teledyne Continental Motors Service Information Letter SIL98-9C stated that the time between overhaul for the IO-470 series engines is 1,500 hours or every 12 years, whichever occurs first. Although advisable, following manufacturer overhaul periods is not required for Part 91 operations.