Narrative:
A United States Marine Corps (USMC) Reserve Lockheed KC-130T Hercules broke up and crashed in the vicinity of Itta Bena, Mississippi, USA. All 16 on board were killed.
The aircraft originated from Marine Corps Air Station Cherry Point, N.C., 1t 14:07 hours to transport personnel and equipment to Naval Air Field El Centro, California.
While the aircraft was flying at 20,000 feet, the number four blade from the number two propeller departed and sliced through the left side of the fuselage, and impacted the interior of the right side, initiating the catastrophic sequence of events. This impact caused the skin of the aircraft to separate along the starboard side. The energy transferred from the propeller blade's impact through the structure of the airframe also caused an overload condition of propeller three's drive shaft. This resulted in its associated reduction gearbox assembly (RGA) failing and the separation of propeller three from the aircraft. Propeller three then momentarily embedded into the upper right section of the fuselage. After which it continued over the aft starboard section of the fuselage and impacted the starboard horizontal stabilizer separating a significant portion of the stabilizer from the aircraft.
The aircraft structure forward of the wings then began to separate, resulting in the cockpit section separating and creating a trail of debris. The absence of the cockpit resulted in the forward section of the central fuselage creating a violent nonaerodynamic drag moment, which exceeded engineering tolerances and greatly accelerated fuselage break up forward of the wing box structure. The fuselage section from the wing box structure aft, continued to fly in a general southwest direction with enough dynamic stability that allowed the fuselage to reenter a downward attitude until final impact in a soybean field.
The investigation determined the cause of the mishap to be an inflight departure of the number four blade from the number two propeller. This propeller blade (P2B4) liberated while the aircraft was flying at a cruise altitude of 20,000 feet . The liberation of P2B4 initiated the catastrophic sequence of events resulting in the midair breakup of the aircraft and its uncontrollable descent and ultimate destruction.
Post-mishap analysis of P2B4 revealed that a circumferential fatigue crack in the blade caused the fracture and liberation. This fatigue crack propagated from a radial crack which originated from intergranular cracking (IGC) and corrosion pitting. The analysis also revealed the presence of anodize coating within the band of corrosion pitting and intergranular cracking on the blade near the origin of the crack. This finding proves that the band of corrosion pitting and intergranular cracking was present and not removed during the last overhaul of P2B4 at Warner Robins Air Logistics Complex (WR-ALC) in the fall of 2011. The investigation concluded that the failure to remediate the corrosion pitting and intergranular cracking was due to deficiencies in the propeller blade overhaul process at WR-ALC which existed in 2011 and continued up until the shutdown of the WR-ALC propeller blade overhaul process in the fall of 2017.
The investigation also examined whether any operational or intermediate level maintenance inspections or maintenance actions exist which could have detected the underlying causal conditions prior to the mishap. The investigation concluded that while these inspections exist, it cannot be quantifiably determined that these inspections would have detected the causal condition. The
investigation arrived at this conclusion due to the fact that the growth or propagation rate of an IGC radial crack cannot be predicted. Though no evidence exists to determine when the radial crack had grown to a detectable area, beyond the bushing, there exists a distinct possibility that it could have been detected if the radial crack had grown past the bushing and the off wing eddy current inspection was performed.
Loss of control
» Military Times
» Marine Plane Had Emergency at High Altitude, General Says (New York Times, 12-7-2017)
accident date: 10-07-2017
type: Lockheed KC-130T Hercules
registration: 165000
| Status: | Accident investigation report completed and information captured |
| Date: | Monday 10 July 2017 |
| Time: | 0.19343900680542 |
| Type: |  Lockheed KC-130T Hercules |
| Operator: | United States Marine Corps |
| Registration: | 165000 |
| MSN: | 5303 |
| First flight: | 1992 |
| Crew: | Fatalities: 8 / Occupants: 8 |
| Passengers: | Fatalities: 8 / Occupants: 8 |
| Total: | Fatalities: 16 / Occupants: 16 |
| Aircraft damage: | Destroyed |
| Aircraft fate: | Written off (damaged beyond repair) |
| Location: | 11 km (6.9 mls) WSW of Itta Bena, MS ( United States of America)
|
| Phase: | En route (ENR) |
| Nature: | Military |
| Departure airport: | Cherry Point MCAS, NC (KNKT), United States of America |
| El Centro-Naval Air Field, CA (NJK/KNJK), United States of America |
A United States Marine Corps (USMC) Reserve Lockheed KC-130T Hercules broke up and crashed in the vicinity of Itta Bena, Mississippi, USA. All 16 on board were killed.
The aircraft originated from Marine Corps Air Station Cherry Point, N.C., 1t 14:07 hours to transport personnel and equipment to Naval Air Field El Centro, California.
While the aircraft was flying at 20,000 feet, the number four blade from the number two propeller departed and sliced through the left side of the fuselage, and impacted the interior of the right side, initiating the catastrophic sequence of events. This impact caused the skin of the aircraft to separate along the starboard side. The energy transferred from the propeller blade's impact through the structure of the airframe also caused an overload condition of propeller three's drive shaft. This resulted in its associated reduction gearbox assembly (RGA) failing and the separation of propeller three from the aircraft. Propeller three then momentarily embedded into the upper right section of the fuselage. After which it continued over the aft starboard section of the fuselage and impacted the starboard horizontal stabilizer separating a significant portion of the stabilizer from the aircraft.
The aircraft structure forward of the wings then began to separate, resulting in the cockpit section separating and creating a trail of debris. The absence of the cockpit resulted in the forward section of the central fuselage creating a violent nonaerodynamic drag moment, which exceeded engineering tolerances and greatly accelerated fuselage break up forward of the wing box structure. The fuselage section from the wing box structure aft, continued to fly in a general southwest direction with enough dynamic stability that allowed the fuselage to reenter a downward attitude until final impact in a soybean field.
Probable Cause:
The investigation determined the cause of the mishap to be an inflight departure of the number four blade from the number two propeller. This propeller blade (P2B4) liberated while the aircraft was flying at a cruise altitude of 20,000 feet . The liberation of P2B4 initiated the catastrophic sequence of events resulting in the midair breakup of the aircraft and its uncontrollable descent and ultimate destruction.
Post-mishap analysis of P2B4 revealed that a circumferential fatigue crack in the blade caused the fracture and liberation. This fatigue crack propagated from a radial crack which originated from intergranular cracking (IGC) and corrosion pitting. The analysis also revealed the presence of anodize coating within the band of corrosion pitting and intergranular cracking on the blade near the origin of the crack. This finding proves that the band of corrosion pitting and intergranular cracking was present and not removed during the last overhaul of P2B4 at Warner Robins Air Logistics Complex (WR-ALC) in the fall of 2011. The investigation concluded that the failure to remediate the corrosion pitting and intergranular cracking was due to deficiencies in the propeller blade overhaul process at WR-ALC which existed in 2011 and continued up until the shutdown of the WR-ALC propeller blade overhaul process in the fall of 2017.
The investigation also examined whether any operational or intermediate level maintenance inspections or maintenance actions exist which could have detected the underlying causal conditions prior to the mishap. The investigation concluded that while these inspections exist, it cannot be quantifiably determined that these inspections would have detected the causal condition. The
investigation arrived at this conclusion due to the fact that the growth or propagation rate of an IGC radial crack cannot be predicted. Though no evidence exists to determine when the radial crack had grown to a detectable area, beyond the bushing, there exists a distinct possibility that it could have been detected if the radial crack had grown past the bushing and the off wing eddy current inspection was performed.
Accident investigation:
 |
|
Classification:
Airframe failureLoss of control
Sources:
» USMC Press Release» Military Times
» Marine Plane Had Emergency at High Altitude, General Says (New York Times, 12-7-2017)
Photos
accident date: 10-07-2017
type: Lockheed KC-130T Hercules
registration: 165000
Video, social media
Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Cherry Point MCAS, NC to El Centro-Naval Air Field, CA as the crow flies is 3543 km (2214 miles).
Accident location: Exact; as reported in the official accident report.
Distance from Cherry Point MCAS, NC to El Centro-Naval Air Field, CA as the crow flies is 3543 km (2214 miles).
Accident location: Exact; as reported in the official accident report.
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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Lockheed C-130
- 2041 built
- 320th loss
- 202nd fatal accident
- 45th worst accident (at the time)
- 47th worst accident (currently)
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