I applied online. The process took 2 months. I interviewed at ICAO (New York, NY) in Apr 2015
Interview
Rather straightforward--I applied online in February, and heard back from ICAO in late March. The first step was a phone interview for about 30 minutes with a combination of fit and aviation industry questions. Nothing too technical; rather, they want someone with a genuine interest in aviation. After the phone interview, there were 2-3 follow-up questions by email, after which I was made a formal, written offer.
Interview questions [1]
Question 1
Tell me about some of the current economic challenges facing the airline industry?