With seven crew onboard, a Lockheed C130A was on a multi-stop flight from Malaysia to Phoenix-Mesa Gateway Airport (IWA) (Arizona, USA) for a C-check maintenance visit. After a fuel stop at Santa Maria Public Airport (SMX) (California, USA) The aircraft took off for its next sector. Shortly after clearing the cloud layer during climb-out, the crew heard a loud popping noise and a bank. At the same time, they observed the engine torque gauges showing abnormal values and fluctuating readings.
The aircraft in its final position (source; asn.flightsafety.org © John Ahlman)
The crew members located in the cargo compartment were confronted with a mist of hydraulic fluid and smoke filling the cargo compartment. They donned supplemental oxygen and informed the flight deck crew of their observations. Bleed air sources from all engines were subsequently turned off. At that time the crew observed the utility hydraulic system pressure fluctuating. To avoid problems extending the landing gear it was decided to lower it at that time, which resulted in three greens being shown, indicating all gears were down and locked. while troubleshooting the multiple failures they were confronted with, the crew turned off the #2 & #4 hydraulic pumps.
A diversion was initiated to Santa Barbara Airport (California, USA) as the weather was favourably compared to other airports close to them. During the flight towards Sanat Barbara Airport, the airplane started to yaw back and forth, while the fire warning light came on in the fire handles for both starboard engines. The #4 engine was shut down, the #3 engine was kept running for performance reasons.
During the remainder of the flight, there were no additional problems and the crew prepared the aircraft for a three-engine landing.
The aircraft in the process of being disassembled for transportation (Source; www.c-130.net © Max Rosenberg)
Upon landing the commander applied full reverse thrust on engines #2 and #3 as soon as the nose landing gear touched down. The right wig started to drop more and more and the aircraft started to the right, left rudder and thrust control were used in an attempt to keep the aircraft on the runway. This was unsuccessful, the aircraft left the runway and was ground-looped in an attempt to avoid parked airplanes and the airport terminal. The airplane came to a stop, approximately 270º right of the runway heading.
Damage to the aircraft was substantial, and concentrated around and on the;
Landing Gear
Right-hand wing
Nose section
The damage was so substantial it was written off.
Federal Aviation Administration (FAA) inspectors identified a failed bleed air duct. According to the operator, the inner wing bleed air duct (part number 19-353632-14) had failed close to the fuselage on the right side of the airplane, allowing hot air to blow
onto the surrounding electrical wires and hydraulic lines.
The aircraft in its final position (source; www.edhat.com © Max Rosenberg)
The failed bleed duct was sent to the National Transportation Safety
Board (NTSB) metallurgical laboratory in Washington, (D.C. USA). There it was determined that the duct (321 austenitic stainless steel) failed as a result of corrosion pitting. Microscopic features observed in the laboratory were consistent with preexisting
cracking before the final circumferential fracture of the duct. This cracking was
located adjacent to the welded joint between the flange and the duct. The cracking was
manifest as a mixed intergranular fracture with cleavage fracture, consistent with lowered
ductility. The lowered ductility was due to the chemical attack inherent in stress corrosion
cracking (SCC). The remainder of the duct remnant fracture was consistent with having
plastically deformed and fractured from tensile overstress.
The National Transportation Safety Board (NTSB) determined that the probable cause(s) of this accident was;
The failure of the No. 3 bleed air duct due to corrosion, resulted in numerous system failures and the pilot’s inability to maintain directional control during the landing roll.
The NTSB report on this accident, which served as the source for this blog can be accessed by clicking on the .pdf file below;
A video of the direct aftermath of the accident is available on Youtube.com;
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