This Advisory Circular (AC) describes an acceptable means of compliance with standards for operators when calculating the piston engine time between overhaul (TBO) for aircraft on mixed agricultural and non-agricultural operations and changing to, or from, agricultural and non-agricultural operations.
This AC relates specifically to Civil Aviation Rule Part 91 and Part 43.
Revision 1 makes minor stylistic and format changes in line with other ACs and adds a version history.
We have also made a marked-up copy of AC91-19 [PDF 362 KB], so changes can be easily checked. As with other ACs, text in yellow highlight denotes insertions and text in strikethrough denotes deletions.
