"With government shutdown threatening paychecks, more TSA agents calling out sick", NBC News; "TSA Workers Are Calling Out Sick as the Government Shutdown Rages On", Popular Mechanics; "Passengers at Sea-Tac miss flights as TSA agents call out sick amid government shutdown", KIRO 7; "TSA says increase in officers calling out sick hasn't impacted travel", WCNC; "Hundreds of TSA screeners, working without pay, calling out sick at major airports", Associated Press; "TSA Screeners Are Calling Out Sick", Bloomberg; "More TSA agents call out sick amid shutdown", Reuters; etc. etc.
Mark Dowson writes:
In my brit English it would be “calling in sick”, by analogy with an employee being told to “call in when you arrive at the work site”. Is this a brit English v. US English distinction?
I don't think so — the phrase I'm familiar with is "[call] in sick" and Google ngrams agrees:
…as does COCA, which finds 390 instances of [call] in sick, as opposed to 7 instances of [call] out sick.
So what's going on with all the TSA employees calling out sick?
My guess is that the "out" belongs with "sick" rather than with "call" — that is, the critical thing is that they're "out sick", i.e. "out due to (alleged) sickness", not that they've dutifully registered this fact (which is probably done via a web app rather than a phone call, though it's still called "calling" just as we "dial" keypads…).
You can't gracefully say that they're "calling in out sick", so "calling out sick" it is.