How do I complain to chair if my advisor regularly writes to scam journals to get tenure? My advisor and his PHD Students are writing regularly to journals published by a publisher, which is on Beall’s list of Predatory Journals. I emailed Beall and he told me that the journals were advertising as non-profit but usually publish if you pay them.

I am in US. So recently the PHD Student and advisor published to this predatory journal’s conference taking place half way down the world and obviously it got accepted. So my advisor approved the student’s trip to that country (almost 1500 $, so it had to be approved by chair), but the chair rejected it saying it’s not worth the expense.

Now I want to directly email my chair and point out to him about my advisor’s publishing record. I am angry that instead of publishing to genuine journals, my advisor (who I believe is incompetent but has good political clout in the university) is publishing to these scam journals and wasting university money to achieve her tenure requirements. 

Since I am still working in lab, I need advice on how to approach my chair so that I can keep myself safe from possible wrath of my advisor and at same time negate the contributions of these journals for his tenure.

Edit 1: The conference listed Google Scholar as one of its sponsors, so I emailed Google and they told me they never sponsored this journal and will order removal of their name from the sponsors list. So yeah, these are all first rate scam journals and I have all these emails, if I ever need to communicate with the chair. I have done my investigation; I just need to get my results across.
Your relationship with your advisor is extremely important for you getting a PhD. I would only contact the chair if you are absolutely certain that you would be able to find a new advisor if things went bad between you and your current advisor. When her tenure comes up for review, someone on the panel will know that these are scam journals. The fact that the chair has already denied one of her expenses means there is likely a red flag in her file (metaphorically). Now if she forces you to publish in one of these journals, you should absolutely complain, but don't complain about what she is doing with other students unless you think it is worth losing your advisor completely and creating enemies in the department. You can talk to the student who actually was going to go to the conference suggest he complains, but ultimately I think that is his responsibility. So again, refer to the first point; make sure you have an escape plan so to speak, and make sure that you are OK with potentially not earning your PhD because you stood up for yourself.