In June 2019, a C-130J in Japan was proclaimed to have achieved Black Letter proficiency; no maintenance problems!
In the official video report, USAF 374th Aircraft Maintenance Squadron crew chiefs explain just how hard it is to get the rare Black Letter:
Here’s official Ramstein Black Letter C-130J video report from May 2018:
VEHICLE I-D: LAST ‘SPOOKY’ DAYS OF THE AC-130U GUNSHIP?