The United States Air Force has chosen to ground almost all of its older C-130H Hercules cargo planes (and their variants). The decision came after recognizing a problem with their propeller barrels.
On the final Friday of September USAF Air Mobility Command (AMC) confirmed a vast majority of their C-130 Hercules fleet are not currently able to fly. The fleet started with 128 planes at the top of fiscal year 2022 and it is not clear how long it could take before they are able to replace every one of the defective propeller assemblies.
According to AMC, at least 116 of these existing C-130 mobility aircraft—including variants—have been grounded since Tuesday (9/27/2022) out of concern for defective propeller assemblies. Apparently, they have scheduled several inspections since then in hopes to identify all of the affected components.
In a recent statement, AMC revealed that the the Warner Robins Air Logistics Complex maintenance crew, in Georgia, have identified a persistent leak during an engine test, even after the C-130H propeller had received depot maintenance. This propeller assembly had been removed and transported to the complex’s repair shop, which is where the technician eyed a crack in the barrel assembly.
With this discovery, Air Mobility Command ordered immediate visual inspections—at the field level—on every C-130H aircraft outfitted with older model 54H60 propeller. They followed this up by conducting metallurgical review and stress analyses. When these reviews concluded, AMC issued another immediate order, in an effort to quickly replace all of the problematic propellers.
AMC has also emphasized that the newer C-130J and C-130H aircraft models, which have already been equipped with upgraded, eight-bladed NP2000 propeller assemblies are not affected by the maintenance order.
It should also be noted that this is now the second time in nearly four years that a significant number of C-130H aircraft has been grounded because of propeller issues. For one, the USAF grounded five dozen C-130Hs for several weeks in February of 2019 to address issues originating from their pre-1971 propeller blades, as they could start cracking. At the time, this was approximately one-third of the fleet; and it took several weeks following to replace those blades.
