This is what I have on the subject...
"A" checks - Performed every 100 hours of operation. Surface examination of skin, brakes, wheels & tires, and engine components are tackled, often in a single day if no corrective measures are required.
"B" checks - Incorporating all the steps of an "A" check, the "B" check, often at 500-hour intervals, provides for more detailed examinations of interior spaces and the engines. It may require some disassembly of airframe over the one to two day process.
"C" checks - Performed every two to three years, the "C" check involves all elements of the "A" and "B" checks, substantial airframe disassembly and detailed engine examinations. It often lasts a week or longer.
"D" checks - Undertaken only on six to eight years cycles, the "D" check is the most involved, requiring complete structural and systems examination and testing, including engine removals, and often results in a virtually rebuilt aircraft after several weeks in the maintenance hanger.
Well, that's it. There are no "E" checks...yet. Hope this helps. Regards.
"Beer is living proof that God loves us and wants us to be happy." --Ben Franklin