Loss of control and mountain impact during engine power loss

3 fatalities • Morton, United States of America • Flight

An aircraft experienced a partial engine power loss during a cross-country flight, leading to an uncontrolled descent and impact with mountainous terrain.

What happened

During a cross-country flight conducted in instrument meteorological conditions, the aircraft was tracked on radar climbing through 14,800 feet MSL approximately 14 minutes after takeoff. The pilot initially notified air traffic control of an intention to return to the departure airfield. Shortly thereafter, the pilot reported an engine failure and reiterated the plan to return to the origin airport. Less than a minute later, the pilot transmitted a final distress message stating, "We’s losing it," after which all radio contact ceased.

Radar analysis indicated that at 14,800 feet MSL, the aircraft entered a continuous right-hand turn at a rate of 8 degrees per second. Approximately 120 degrees into this maneuver, the aircraft began a rapid descent at an average rate of 5,783 feet per minute. The aircraft continued this right-hand turn until radar tracking was lost at 10,700 feet MSL. The aircraft eventually struck a 30-degree slope of a heavily forested mountain at an altitude of approximately 2,940 feet MSL. At the moment of impact, the aircraft was in a near-vertical attitude with the right wing slightly low. An eyewitness in the vicinity reported hearing a loud, high-power roaring sound during the descent, noting that the weather was characterized by light rain and low visibility.

Findings

Post-accident investigations determined that the propeller damage was caused by the impact itself, with no evidence of pre-impact fatigue or mechanical failure. Analysis of the engines showed that the left propeller was producing power at the time of impact, while the right propeller was not producing significant power. Investigators concluded that the pilot likely experienced a partial loss of power in the right engine and subsequently initiated an incorrect right turn into the failed engine. This maneuver caused the turn rate to increase until the aircraft became uncontrollable, leading to the fatal impact with the terrain. The specific cause of the partial power loss remained undetermined, as no mechanical malfunctions were found in the airframe or engines during the examination.

Probable cause

The pilot likely experienced a partial loss of power in the right engine and initiated an improper turn into the failed engine, resulting in an uncontrollable descent into terrain.

Frequently asked questions

What happened in the 2010-10-25 Cessna 340 accident near Morton, United States of America?

An aircraft experienced a partial engine power loss during a cross-country flight, leading to an uncontrolled descent and impact with mountainous terrain.

Were there any fatalities in the 2010-10-25 Cessna 340 accident?

The accident was fatal, resulting in 3 fatalities.

What aircraft was involved and where did it happen?

The accident on 2010-10-25 involved a Cessna 340, registration N68718, operated by Pacific Cataract and Laser Institute, at Morton, United States of America.

What was the probable cause of the accident?

The pilot likely experienced a partial loss of power in the right engine and initiated an improper turn into the failed engine, resulting in an uncontrollable descent into terrain.

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