Incident Overview

Date: Friday 22 November 1996
Aircraft Type: Lockheed HC-130P Combat King
Owner/operator: United States Air Force – USAF
Registration Number: 64-14856
Location: 64 km W off Cape Mendocino, CA, USA – ÿ Pacific Ocean
Phase of Flight: En route
Status: Destroyed, written off
Casualties: Fatalities: 10 / Occupants: 11
Component Affected: All four engines.All four engines.
Category: Accident
On October 26, 2023, at approximately 17:20 PST, a Lockheed HC-130P Combat King aircraft (callsign ‘King 56’) experienced a significant in-flight emergency due to a torque flux on one engine, leading to instability and subsequent engine failure. The aircraft initiated a four-engine rollback procedure, including placing all four propellers in mechanical governing, and subsequently turned eastward towards Kingsley Field, Oregon, approximately 230 miles from the coast. The incident was reported to the USCG Humboldt Bay Station.On October 26, 2023, at approximately 17:20 PST, a Lockheed HC-130P Combat King aircraft (callsign ‘King 56’) experienced a significant in-flight emergency due to a torque flux on one engine, leading to instability and subsequent engine failure. The aircraft initiated a four-engine rollback procedure, including placing all four propellers in mechanical governing, and subsequently turned eastward towards Kingsley Field, Oregon, approximately 230 miles from the coast. The incident was reported to the USCG Humboldt Bay Station.

Description

The Lockheed HC-130P Combat King aircraft departed Portland International Airport, Oregon, USA at 17:20 PST on an instrument flight rules (IFR) flight en route to North Island Naval Air Station at San Diego, California. The purpose of the sortie was to conduct an overwater navigation evaluation. The aircraft, with callsign ‘King 56’, began the sortie with a normal takeoff, departure and climbout. One hour and 24 minutes after takeoff in level flight at FL 220 the mishap sequence began with the engineer commenting on a torque flux on the number 1 engine. Over the next three minutes, the operations of all four engines became unstable and eventually failed. The engineer called for number 1 propeller to be placed in mechanical governing. This would normally remove electrical inputs to the propeller through the synchrophaser. The pilot then called for all four propellers to be placed in mechanical governing. This action was consistent with treating this emergency as a four-engine rollback. There is no indication on the DFDR or the CVR as to whether or not the crew selected mechanical governing on any of the remaining three propellers. At the same time the crew was analyzing the emergency, they also declared an in-flight emergency with Oakland ARTCC and turned the mission aircraft east to proceed toward Kingsley Field, Klamath Falls, Oregon, approximately 230 miles away and approximately 80 miles from the coast. The Radio Operator radioed the USCG Humboldt Bay Station and notified them of the in-flight emergency. During the turn toward the shore the number 3 and number 4 engines once briefly recovered most of their torque. These increases are recorded by the flight data recorder. When the RPM on number 3 (the aircraft’s last functioning engine) finally decreased below 94% RPM the last generator producing electrical power dropped off line due to low frequencies. As a result, at 18:46 Pacific Standard Time all electrical power was lost. After a brief period, power was restored to the equipment powered by the battery bus. From this point on, the aircraft glided to the attempted ditching. Cause: Fuel starvation.

Source of Information

https://fas.org/man/dod-101/sys/ac/docs/c-130-bar.htm#6.1https://fas.org/man/dod-101/sys/ac/docs/c-130-bar.htm#6.1

Primary Cause

Torque flux on one engine caused instability and subsequent engine failure, triggering a four-engine rollback.Torque flux on one engine caused instability and subsequent engine failure, triggering a four-engine rollback.

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