Best study tool for COM oral exam prep?
In conjunction with the ASA Commercial Pilot Oral Exam Guide, use the Commercial ACS. The ACS is what the examiner uses to administer the checkride. Go through the ACS line-by-line to make sure no stone goes unturned, so to speak.
The FAR/AIM also has a TOC near the front with a list of every reg and AIM chapter that relates to commercial knowledge.
Also, review your private knowledge! This is the most common thing overlooked.
I am a big fan of the ASA Oral Exam Guide. I used it for all of my check rides and occasionally still look at them for review.
+1 on the ASA Oral Exam Guides, used each one for every checkride, I also used YouTube for “Mock Checkride” completions as there are tons of Full-time Instructors like Fly8MA and MzeroA who give really good tips and suggestions as well.
I for one love the ASA books, but I think it’s worth noting that ATP is no longer providing them in the start up box. The ASA book is great when used properly. It shouldn’t be your primary source for knowledge, but used more of a tool to quiz yourself after you actually understand the material.
I suggest using the ACS as your primary source. Use the ACS and reference material listed at the top of the pages. Once you get the knowledge down, switch over to the exam guides (like ASA)/ videos to quiz yourself. Try not to rely solely on rote memorization.
Great advice from everyone so far, I just wanted to add my thoughts. I personally never was able to make it that far in the ASA books, not that they are a bad resource. They are very dense and difficult to read if you just try and use them as a primary study source. I found that some of the questions were so detailed that a DPE would never ask them. I personally only used them within the last couple of weeks before the checkride to review possible questions. The best resource that I think helped me significantly was the recommended regulations/AIM topics listed in the front of the FAR/AIM. Reading through each of the pertinent regulations for each checkride, then highlighting and adding tabs to your FAR/AIM made it so that I had learned a majority of the required knowledge straight from the source. Some of the verbage in the FAR/AIM is very particular, and knowing the exact wording in the regulation will help you when the DPE asks you a secondary question to see the depth of your knowledge. And if you forgot any regulation, you can simply find your tab and then find the highlighted material. The DPE will be much happier, compared to you spending 5 minutes flipping through trying to find where the regulation actually exists. And then as Brady mentioned, there are a lot of great mock checkrides on YouTube that will give you an idea how the questions are typically asked and what the expectation should be. For commercial make sure you have built upon your private knowledge, understand aircraft systems well, and understand what circumstances you can legally be paid to fly.
Hope this helps!