Home » Aviation » Investigation: Corroded Propeller Blade Caused KC-130T Crash


Investigation: Corroded Propeller Blade Caused KC-130T Crash

A U.S. Marine Corps KC-130T aircraft from VMGR-452 prepares to taxi during Weapons and Tactics Instructor Course (WTI) 2-15 in Yuma, Ariz., April 11, 2015. WTI is a seven-week event hosted by Marine Aviation Weapons and Tactics Squadron One (MAWTS-1) cadre. US Marine Corps photo.

The Marine Corps determined that a corroded propeller blade that came off mid-flight was the cause of the July 10, 2017, crash of a KC-130T transport plane.

That propeller did not go through proper maintenance the last time it was sent to an Air Force repair depot, which may have led to the damaged propeller remaining on the airplane that ultimately crashed and killed all 16 personnel onboard.

The Marine Corps released a partially redacted Judge Advocate General Manual Investigation today, which found that “the investigation found the primary cause of this mishap to be an in-flight departure of a propeller blade into the aircraft’s fuselage. … The investigation determined that the aircraft’s propeller did not receive proper depot-level maintenance during its last overhaul in in September 2011, which missed corrosion that may have contributed to the propeller blade liberating in-flight,” according to a Marine Corps press release on the investigation.

Marine Forces Reserve conducted the investigation and has made several recommendations for Naval Air Forces and for the Air Force to consider for their C-130 fleets.

The Crash

On July 10, 2017, a crew from reserve unit Marine Aerial Refueler Transport Squadron 452 (VMGR-452) departed their home station at Stewart Air National Guard Base in New York and flew to Marine Corps Air Station Cherry Point, N.C. Their mission for the day was to transport six Marines and a Navy corpsman assigned to 2nd Marine Raider Battalion from North Carolina to Naval Air Facility El Centro, Calif., where the special operations unit was set to conduct pre-deployment training.

The aircraft departed Cherry Point at 2:07 p.m. Its last transmission to local air traffic control was at 3:46 p.m., and the last radar contact with the plane was at 3:49, when the plane was flying at 20,000 feet altitude, according to the JAGMAN.

The Marine Corps investigation found that Blade 4 on Propeller 2 (P2B4, in the report) became unattached, struck the port side of the fuselage, cut straight through the interior of the passenger area of the plane and became lodged in the interior of the starboard side of the plane. This damage kicked off a series of events that led to Propeller 3 colliding with the starboard side of the fuselage and ultimately the plane breaking into three pieces mid-air.

The cockpit and the rear of the fuselage crashed into two separate debris fields in a soybean field near Itta Bena, Miss. The middle section of the plane, where the passengers were located, further broke up in the air.

Marine Corps leadership made clear there was nothing the crew or passengers could have done to prevent the mishap or save themselves once the propeller blade broke loose.

Brig. Gen. Bradley James, commanding general of 4th Marine Aircraft Wing, which oversees the reserve KC-130T squadron, wrote in the investigation report that “the initial incident that started the cascading failure was the liberation of a blade from the #2 propeller assembly. The subsequent events quickly led to structural failure of the aircraft. Neither the aircrew nor anybody aboard the KC-130T could have prevented or altered the ultimate outcome after such a failure.”

Pictures of the Marines and sailor who died in a KC-130T cargo aircraft on July 10, 2017. USMC Photos

Killed in the crash were: Maj. Caine Goyette, an active duty Marine who was flying the plane the day of the crash, who the report found was current on all his certifications and had 2,614 hours of flight time in military aircraft; Capt. Sean Elliott, an active duty Marine who co-piloted the plane and had 822 hours of military aircraft flight experience; Gunnery Sgt. Mark Hopkins, Gunnery Sgt. Brendan Johnson, Staff Sgt. Joshua Snowden, Sgt. Owen Lennon, Sgt. Julian Kevianne, Cpl. Collin Schaaff and Cpl. Daniel Baldassare, who were part of the VMGR-452 crew; and Staff Sgt. Robert Cox, Staff Sgt. William Kundrat, Sgt. Chad Jenson, Sgt. Talon Leach, Sgt. Joseph Murray, Sgt. Dietrich Schmieman and Petty Officer 2nd Class Ryan Lohrey, who were assigned to 2nd Marine Raider Battalion.

Maintenance Failures

Though no one on the plane could have stopped the events that unfolded, the maintenance community could have prevented them. The investigation found a failure to inspect the propeller during its last depot maintenance period, as well as missed opportunities during squadron-level maintenance to potentially notice the corroded blade.

The plane itself was 24 years old and was last in depot maintenance at Warner-Robbins Air Logistics Complex (WR-ALC) in Georgia in August 2011 for blade overhauls. The Air Force complex is manned by civilian employees who rework and overhaul propellers and is the sole source of this overhaul work for Navy and Marine Corps C-130s.

According to the JAGMAN, the Navy and Marine Corps require C-130 propellers to undergo an overhaul every 5,000 to 6,000 flight hours. Investigators studying the plane wreckage found not only corrosion in the Blade 4 Propeller 2, but found anodize coating inside the corrosion pitting – which means the corrosion was there during the 2011 overhaul, and instead of removing the corrosion and fixing the blade, the coating was applied over the damaged blade.

“Negligent practices, poor procedural compliance, lack of adherence to publications, an ineffective [quality control/quality assurance] program at the WR-ALC, and insufficient oversight by the [U.S. Navy], resulted in deficient blades being released to the fleet for use on Navy and Marine Corps aircraft from before 2011 up until the recent blade overhaul suspension at WR-ALC occurring on 2 September 2017,” reads the JAGMAN, referring to the September “Redstripe” standdown of all Navy C-130s until further blade inspections could be conducted.

Twelve of the 16 total blades on the plane that crashed – four blades on each of four propellers – “were determined to have corrosion that existed at the time of their last overhaul at WR-ALC, proving that over the course of the number of years referred to above, that WR-ALC failed to detect, remove and repair corrosion infected blades they purported to have overhauled. … Thirteen of the sixteen blades on the [mishap aircraft] had other discrepancies proving that, over the same span of years referred to above, WR-ALC was deficient in the effective application of the following steps: anodization, epoxy primer and permatreat,” the JAGMAN continues.

Though less severe than the failure at the Air Force depot, the report noted concerns with maintenance practices within the squadron earlier in 2017, in the months before the crash.

According to the JAGMAN, the squadron failed to establish a formal process to track and perform the 56-day conditional manual inspections of the propeller blades that can be triggered when the plane is not used or when the blades are not rotated for 56 days. Due to a lack of a clear procedure, on at least two occasions in 2017 a conditional inspection was triggered, but the squadron believed that separate inspections met the requirement and therefore the maintainers did not do the manual blade inspection. However, the investigation notes that it could not be determined whether a manual inspection could have identified the damage to the blade that led to it becoming detached mid-flight and causing the crash.

Recommendations

In August 2017, a Navy engineering team conducted a process audit at Warner-Robbins Air Logistics Complex and found that, even though the Navy and Marine Corps have separate blade overhaul procedures and standards from the Air Force, the civilian workforce had failed to track which blades belonged to which service and therefore which maintenance standards to apply. Only about 5 percent of the blades belong to Navy and Marine Corps planes, but the Navy recommended creating a standard work flow process and the Air Force agreed to adopt all the Navy’s processes.

The report also recommends that Warner-Robbins Air Logistics Complex maintain electronic records of all blade overhauls that can be kept permanently, compared to the paper records that are discarded after two years. It also recommends greater Navy oversight of Navy/Marine Corps overhauls at Warner-Robbins, blade overhauls at a more frequent interval than 5,000 hours, and additional clarity on the 56-day inspections.

  • Corporatski Kittenbot 2.0

    Pertinent timing given Japan.

    Flogging an old fleet into the ground across the entire planet costs lives… and will cost many more.

    Its all about political choices.

  • buzzard767

    I’m sure I flew that Herc when it was in VMGR-234 at NAS Glenview in the 70’s. God bless the crewmembers. Hopefully it was freakish bad luck and not due to lack of funding for the military until recently.

    • TFD

      The plane was delivered new in 1993. Buno Number 165000.

      • buzzard767

        Oh yeah. I see that now. One of my former squadron mates emailed me and said it was one of the planes sent to New York when VMGR-234 at Glenview was split up.

  • Ike_Kiefer

    Air Force literally painted over the propeller corrosion. Murderous maintenance malpractice.

    • Donald Carey

      Not the Air force, civilian contractors. It could even be deliberate sabotage.

  • Bubblehead

    You really have to wonder if the latest crash in Japan is the same reason. Historically C-130’s are about the safest thing on the planet to fly, but anything is dangerous if proper maintenance procedures are ignored or not followed.

    But we will hold off until the investigation is complete before further speculation.

    • Duane

      It would certainly be worthwhile following up on every prop overhauled by the non-compliant AF prop shop and order new inspections on all such props still in service. If one overhaul was performed negligently by that crew and facility, then it is likely that others were done incorrectly too.

    • Scott1945est

      C-130J’s use COMPLETELY different engines and propellors.

      Want to explain the Hornet loss in the Japan accident?

      • Duane

        Non-compliant propeller maintenance has nothing to do with the manufacturer of the engines and props. That is what Bubblehead was referring to.

  • Duane

    The prescribed 5,000 hour prop overhaul schedule seems very long. For most commercial and private light aircraft, prop overhauls are typically performed at least every 2,000 hours, or more often based upon condition. And it goes without saying, the overhaul must be performed correctly and according to published procedures.

    An aircraft propeller blade may seem to be a very simple component, but it is exposed to very high mechanical stresses and to all manner of environmental stresses, including dirt, rocks, debris, moisture, salt, etc. It doesn’t take much to start a small pit or micro crack that can, under the stress of high rpm and vibration, propagate to a failed blade. A failed propeller blade is a catastrophic structural failure.

  • Secundius

    I’d like to know who the Lieutenant Colonel of VMGR-452 “IS”! HE’s the Squadron Commander, the KC-130T(s) were specifically assigned to HIM! NOT the Air Force Maintenance Crew assigned to Maintain the Aircraft’s. IT’s His responsibility for the Overall Care and Maintenance needs of the Aircraft’s, not the Air Force Crew Maintaining the Aircraft’s…

    • Duane

      Prop shops are the experts in prop maintenance, not field shops. There were apparently some misteps in the local maintainer group, but primary responsibility goes to the AF prop shop which did not follow procedure and failed in their job. The Marines’ report makes that quite clear.

      • Secundius

        Keep in mind this was a USMC aircraft! That being said, most Air Force Mechanics “Aren’t” going to be knowledgeably in the Color Scheme of USMC aircrafts. Unless the Complete Maintenance Logs of THAT particular aircraft was part of THEIR records. There going to treat it as is, USMC property and do the BASIC maintenance required to make it flyable, and nothing more…

        • Duane

          You’re not getting it. The AF prop shop failed to follow the required overhaul procedure, which proved to be the cause of the prop blade failure. It matters not what the paint scheme is. The prop shop does not need to know or maintain the full lifetime maintenance record of the prop – they need to inspect and repair as required in accordance with the published procedures for that particular prop, and then properly document exactly what they did, and that what they did complied with the published procedures.

          But the AF prop shop failed to do that.

          That isn’t my conclusion – that was conclusion of the Marine board that produced the accident investigation report.

          • Secundius

            Always assuming that THEY (i,e, USAF) were told to do it, and NOT performed by USMC Maintenance Crews…

  • George Hollingsworth

    The serial number of this particular blade should have been noted and its history since new outlined in the report. If the results were as stated and also that there were multiple other blades on the accident aircraft that demonstrated corrosion that had been plated over then quite possibly every C-130 belonging to any service who has had their blades overhauled by this facility are suspect. The implications are as serious as it gets.

  • Pete Novick

    The Navy has a term for it: gundecking.

    So, why is there always enough time to get it right the second time?

  • RunningBear

    I appreciate the corroded prop blade was the initiator for the accident but…..the whole propeller hub broke off the opposite side engine and cutoff the cockpit from the aircraft fuselage.

    That hub, 4 blades and gearbox is a bit more substantial in destroying the aircraft inflight, chopping off the forward cockpit section and tearing off the starboard horizontal stabilizer; either one is dooming the aircraft crew totally aside from the loss of the one blade.

    The corrosion issue is horrible enough but what the “heck” caused an un-involved engine to break “in-two” and complete the “wound” to catastrophic death?
    IMHO
    Fly Navy
    🙂

    • old guy

      Absolutely correct. Blade corrosion has NOTHING to do with a hub seperation. Ever see one of those, Sonething VERY serious here, even beyond the trajedy.

      • Duane

        The Marine investigation board did not conclude that corrosion caused the blade to fail in flight. The board blamed the AF prop shop for concealing an existing crack in the blade with an anti-corrosion coating instead of grinding out the crack as part of an overhaul per procedure. It was that specific crack that then propagated through the blade in flight causing it to fail and fly through the fuselage and eventually impact with the inboard engine/hub on the opposite side.

    • Duane

      The blade that broke off from engine no. 2 penetrated the fuselage and impacted with its opposite number on the other inboard side. That’s the proximate cause for the other prop hub to depart and then slice thru the horizontal stabilizer which caused loss of pitch control. But the impact of the destruction of the fuselage led to the breakup of the aircraft

  • old guy

    Blade corrosiuon does NOT make a C-130 throw a blade. I have flown in old birds whose blades were so bad, that they lost some thrust, requiring adjustments, but this “The Marine Corps investigation found that Blade 4 on Propeller 2 (P2B4, in the report) became unattached,” The Hub problem may be due to retention parts, but not “blade corrosion.” If the blade was that corroded, the vibration on start up would have been tremendous.

    • Duane

      The corrosion of the blade did not cause the blade to depart. What caused the blade to depart was the in-flight propagation of a specific crack in the blade that had been visually covered up by a corrosion treatment coating.

      The corrosion was covered up by the prop shop that failed to follow the prescribed overhaul procedure. Essentially the blade should either have been ground down, within prescribed geometric limits as part of a normal overhaul to remove any pits or cracks that serve to concentrate blade stress, or if that was not feasible, then replace the entire blade

    • Ike_Kiefer

      Corrosion, when it is bad enough to cause pitting as it was in this case, causes stress concentrations to build up which can lead to intragranular cracking. If you read the report, they found the anodize coating applied by Air Force depot-level maintenance both on top of the corrosion pitting and inside the cracks radiating out from the pitting. So cracks in the prop blade were clearly present and growing undetected since at least 2011.

      • Secundius

        If that’s true, then it’s not a Rolls-Royce problem. But a Dowty Propeller (i.e. General Electric Aviation Systems) problem. They produce the 6-bladed propellers…

        • Ike_Kiefer

          Any OEM component can fail if it is not properly maintained. I think there is a reasonable debate on whether the 5,000-hr TBO for the prop blades was too long, and if the Marine squadron maintenance personnel should have been able to detect the growing defect leading to the failure on their regular inspections. But bottom line is that corrosion is a normal threat and there are procedures in place to mitigate it, but they were not followed in this case.

          • Secundius

            As I recall, the TBO for the Rolls-Royce AE-2100D3 is around 4,000-hours, NOT 5,000-hours. At least that’s what’s claimed by Rolls-Royce. Original engine design is by Allison Engines, which is NOW Rolls-Royce…

          • TFD

            This was a legacy KC-130 with Allison T-56 engines and Hamilton Standard propellers.

          • Secundius

            The “T” model doesn’t use Allison Engines, because Allison Engines no longer exist. It uses Rolls-Royce engines, an upgraded Allison which is now owned by Rolls-Royce. It also doesn’t use Hamilton Standard either, but rather Dowty Propellers instead. Dowty is a subsidiary owned by General Electric Aviation Systems…

  • RunningBear

    Just as a slight aside, “HOW MANY” C-130 type engines have lost an entire propeller hub and in this instance the attached gearbox?……and why?
    Over the course of the life of the program, several/ many?? P-3s (similar engine) have disappeared on routine patrol over the oceans with no known cause or locations.
    Fly Navy
    🙁

    • Secundius

      Scroll down to (d) Unsafe Conditions…

      ( https : // www . federalregister . gov / documents/2015/02/04/2015-01282/airworthiness-directives-rolls-royce-corporation-turboprope-and-turbofan-engines-type-certificate )

      Sorry about format, but USNI News tends to Redact Information Sources…

  • George Hollingsworth

    How is squadron or wing level maintenance supposed to find corrosion that has been plated over?

    • Secundius

      AC Number 35.37-1B…

      https : // www . faa . gov / documentLibrary / media / Advisory _ Circular / AC _ 35 _ 37 – 1B . pdf

      • George Hollingsworth

        There is no such AC as you listed.

        • Secundius

          That’s what it was called in 2011, try logging onto anyone of the “pdf” files marked “Advisory Circular”! Other than that, I can’t help you…

  • George Hollingsworth

    The cause of the #3 engine gearbox becoming overloaded and separating on the right side, along with the entire #3 propeller, as a result of a blade leaving the #2 engine on the left hand side is not stated or implied very clearly.