The Derg years saw the ETAF embroiled in the civil war. The ETAF played a critical role in the Derg's war effort in the north. It was the main stumbling block the rebels faced from achieving total victory. However, in the late 1980s, many in the air force began questioning the prosecution of the war. Following the failed coup of 1989, in which the ETAF's top leaders participated, its high command was decimated with arrests and executions. As a result, ETAF was suffering from low morale and serious internal rifts. Pilots were defecting in increasing numbers to neighboring countries. The situation on the ground was also becoming hopeless. Eventually, the forces of the Ethiopian People's Revolutionary Democratic Front (EPRDF) overran the Derg's army and took control of the country in 1991.