Mugunus,
Completing any writtens ahead of your start date is a recommendation, it is not a requirement. The more you can complete now if you don’t have a start date, the lighter the load will be when you do officially start. Since you did not give us a potential start date, Airman Knowledge Tests’ scores expire after 24 months, so be diligent with how early you take these tests. If you plan to start ATP in the next few months, that shouldn’t be an issue, but a start date next fall could raise concerns if you get stumped along the way in program. Once you complete your PAR (which you may study with whatever material you find, we recommend Sporty’s Study Buddy App), you will use Sheppard Air and the rote memorization method to complete the other writtens. You may learn the material, but it seriously is a “check in the box” for written exams and you want to get the best score as possible, a 100%. We have an short guide of how to prepare for a AKT:
The most common failure I saw occurring is lack of preparation/unprofessionalism. ATP lays out the foundation of your training through a standardized program which every student receives the same training across all 70+ locations. When I was a lead instructor at ATP, I emphasized the importance of coming prepared to every flight that I did with a student, those that did not come prepared either had their flight cancelled or they received a training improvement plan to get things figured out for success. I would say I think during my 13ish months in honesty I seen 3 out of dozens maybe not make it through the program. And it all reflects back to preparation and readiness.
Is failing a checkride easy? Well yes, it is just like failing a test during your primary education and that comes from a result of my above explanation to why I think individuals fail during their program. There are other extremities that we can’t predict, like getting sick and having a desire to really complete the checkride or factors that you get tunnel visioned. Thankfully ATP provides students with a “Checkride Checklist” to ensure you have everything prepared for the checkride. I would say half/half would either fail the oral or flight, because you have to make it through the oral to get to flying. Setting the tempo and impression early will make a difference, come into the checkride unprepared and not professional, a DPE will sense it.
Tory linked a good FAQ article on what you need to do to be successful at ATP.
Brady