In July 1966, Major General Udugama was suspended and arrested under emergency regulations following allegations of attempting stage a coup against the government of Prime Minister Dudley Senanayake. Colonel Heyn, who was acting army commander in Major General Udugama's absence abroad, continued until he was confirmed as army commander on 11 November 1966 with the promotion to the rank of brigadier. He was later promoted to the rank of major general and held the post till his retirement on 30 September 1967.