CEN21LA057

The private pilot and three passengers departed on a personal flight in visual conditions. As the airplane approached its destination while at an altitude of about 900 ft above ground level, the pilot received cockpit indications of erratic high engine oil temperature. About 5 seconds after the indications began, the pilot moved the throttle to idle power and likely adjusted the fuel-air mixture. About 3 seconds after moving the throttle to idle power, the pilot advanced the throttle to a cruise power setting, but the fuel flow and engine power did not increase. The pilot made additional throttle movements, but the fuel flow and engine power did not correspond to throttle movements most likely because the pilot had adjusted the fuel-air mixture toward a lean setting. Thus, the pilot’s actions in response to the high engine oil indications led to the loss of engine power. Without engine power, the airplane’s airspeed decreased to about 85 knots, and the pilot successfully deployed the airplane’s parachute system. Postaccident examination revealed no anomalies that would have precluded normal engine power. The oil temperature connector and back shell were damaged, with the back shell disconnected from the oil temperature connector. The accident flight was the first after maintenance work during which a crush gasket adjacent to the damaged oil temperature connector was replaced. The oil temperature connector was most likely damaged during this maintenance and resulted in erratic indications of high engine oil temperature during the accident flight.

On October 24, 2020, about 1200 central daylight time, a Cirrus SR22 airplane, N183V, was substantially damaged when it was involved in an accident near Tishomingo, Oklahoma. The pilot and the three passengers sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. During a postaccident interview, the pilot recalled that, while the airplane was descending toward its destination (Atoka Municipal Airport, Atoka, Oklahoma), he was alerted to high oil temperature indications and noted a loss of engine power. The pilot stated that he attempted to restore engine power by adjusting the air-fuel mixture and throttle but was unable to do so. Download of the airplane’s remote data module revealed that, while the airplane was approaching its destination at an altitude of about 900 ft above ground level, erratic high engine oil temperatures (from 314°C to 801°C) were recorded for 5 seconds. The engine oil temperature returned to normal for the next 7 seconds, which was followed by erratic high temperatures for the remainder of the flight. According to (source), engine oil temperatures greater than 240°C triggered a flashing red warning cockpit annunciator and an aural chime every 1.5 seconds. The downloaded data from the remote data module also showed that, about 5 seconds after high oil temperatures began, decreases in fuel flow, manifold pressure, and engine rpm were recorded, which were consistent with throttle movement to idle power. About 3 seconds later, manifold pressure increased, consistent with a throttle increase, but fuel flow indications remained near 3 to 5 gallons per hour. The manifold pressure subsequently decreased and increased twice with no corresponding change in fuel flow. The pilot then assessed the available locations for a forced landing and determined that the options were unsuitable. As a result, he activated the Cirrus Airframe Parachute System. The downloaded data showed that the parachute activation occurred about 45 seconds after the high oil temperatures began and that the airplane’s airspeed at the time of activation was about 85 knots. The airplane descended under the parachute and impacted terrain, resulting in substantial damage to an airframe engine mount. Postaccident examination of the engine revealed normal mechanical continuity. The fuel inlet filters were clear of debris, and no anomalies were noted with the ignition leads, spark plugs, magnetos, fuel servo, flow divider, or fuel injectors. The oil reservoir was empty, with the several holes in the oil pan due to impact damage. The oil temperature connector and back shell were damaged, and the back shell was disconnected from the connector. The accident flight was the first flight after maintenance was performed to address high engine oil consumption during previous flights. The logbook entry for this maintenance included replacement of crush gaskets on the oil cooler housing. One of the crush gasketsthat was replaced was adjacent to the damaged oil temperature connector. According to a Federal Aviation Administration Safety Team (FAAST) publication: General aviation accidents often result from inappropriate responses to unexpected events. Humans are subject to a “startle response” when they are faced with unexpected emergency situations and may delay action or initiate inappropriate action in response to the emergency. Training and preparation can reduce startle response time and promote more effective and timely responses.