The ATP PTS outlines what should be covered on the checkride. There is an emphasis on aircraft systems and you prove mastery of the aircraft by flying several different instrument procedures. Not much mentioned outside of that.
Satisfactory Performance
The ability of an applicant to safely perform the required Tasks is based on:
...
2. demonstrating mastery of the aircraft with the successful outcome of each Task performed
never seriously in doubt (14 CFR section 61.43(a)(2));
“Satisfactory knowledge” means the applicant’s answer contains at least 70 percent of the reference answer to the examiner’s question (“textbook answer”) and if the applicant’s actions followed his/her response, the safety of the airplane would never be seriously in doubt.
Typical areas of unsatisfactory performance and grounds for disqualification are:
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3. Consistently exceeding tolerances stated in the Objectives.
4.
Failure to take prompt corrective action when tolerances are exceeded.
The oral exam looks like this:
Task A: Equipment Examination (systems)
(Pg. 25 of the PTS covers the specific aircraft equipment and demonstrating knowledge)
Task B: Performance and Limitations (can you use the performance charts and graphs?)
Section 2, Task A: Preflight procedures
Objective: To determine that the applicant:
1. Exhibits satisfactory knowledge of the preflight inspection
procedures, while explaining briefly—
a. the purpose of inspecting the items which must be checked.
b. how to detect possible defects.
c. the corrective action to take.
Then the flight portion: 2 Precision approaches: 1 coupled, 1 hand flown, 1 single engine. 2 Non-precision: 1 GPS, 1 Circle to land. Holding, 2 missed approaches, 1 single engine missed, and a few other minor checkboxes to fill...
That being said:
Know the limitations before you show up!!! Flashcards are sent out... USE THEM!!! and you will do just fine!