### Question
How does AIR COMMERCE AND SAFETY define heavy maintenance work?


### Answer
Under *49 U.S.C. § 44733*, **heavy maintenance work** is defined as:

> a C-check, a D-check, or equivalent maintenance operation with respect to the airframe of a transport-category aircraft

#### Citation:
  - *49 U.S.C. § 44733*
  - Heading: **SUBTITLE VII-AVIATION PROGRAMS > PART A-AIR COMMERCE AND SAFETY > subpart iii-safety > CHAPTER 447-SAFETY REGULATION**

