The interview process was protracted and inefficient. The application in total took over half a year: I was invited to apply for the job in June, took a skills test in August, interviewed in October, finally received a provisional job offer in December (at the latest possible moment before the holidays), and in January began a demanding and adversarial vetting process that ended with my refusal a few months later. There was no communication from the employer in the early stages, and I often assumed they had moved on to another candidate. During the interview, I asked about basic job details (which were absent in the ad) and was refused transparency. I should have followed my instincts at that warning sign.
Ultimately, I declined the offer due to invasive and unnecessary medical tests they pressured me to take (even though no physical requirements were indicated in the job ad, and no mention of these tests occurred in the application process). They also threatened not to refund some of the tests I did complete if I declined the offer, which is a different story! (I was reimbursed seven months later, after much hassle.)
In sum, the ICAO values rigid adherence to policy over expertise or industry standards. I cannot recommend it as an employer.