C check
This is performed approximately every 20–24 months or a specific amount of actual flight hours (FH) or as defined by the manufacturer. This maintenance check is much more extensive than a B check, requiring a large majority of the aircraft's components to be inspected. This check puts the aircraft out of service and until it is completed, the aircraft must not leave the maintenance site. It also requires more space than A and B checks—usually a hangar at a maintenance base. The time needed to complete such a check is generally 1–2 weeks and the effort involved can require up to 6000 man-hours. The schedule of occurrence has many factors and components as has been described, and thus varies by aircraft category and type.
http://en.wikipedia.org/wiki/Aircraft_maintenance_checks

CRS = Cost Repercussion Sheet
https://www.google.ru/#newwindow=1&tbs=li:1&q=aviation CRS C...

Tally Sheet - учетный листок