He initially saw service in the New Zealand military, but joined the Royal Australian Air Force in 1949 and graduated as a sergeant pilot in 1951.

Drummond was promoted to acting wing commander in December 1965 and posted to South Vietnam on staff duties with the United States Air Force.

That month he earned the Distinguished Flying Cross for his part in rescuing a company of soldiers surrounded by Viet Cong forces.

Drummond enlisted in the Royal New Zealand Air Force (RNZAF) in May 1944 and trained as a navigator; he graduated in September 1945 and was discharged with the rank of sergeant in October.

[1][2] Returning to New Zealand in October 1948, Drummond tried to transfer to the RNZAF as a trainee pilot but was considered too old; he successfully applied to the Royal Australian Air Force (RAAF) and enlisted in August 1949.

[1] His brother Frederick Agnew Vance Drummond (1921–1941) had died on active service with the RAAF during World War II.

1 Flying Training School in Point Cook, Victoria, Drummond ditched his CAC Wirraway into Lake Corangamite during a low-level exercise.

[4][5] He was at an altitude of 200 feet (60 m) when he went to adjust his compass and accidentally knocked his control column forward, causing the Wirraway to dip and strike the water.

The RAAF investigation found that although Drummond was technically at fault, the "glassy" surface of the water and the awkward position of the compass in the Wirraway were the prime causes of his "aquatic adventure".

The squadron had gone into action a week after the outbreak of the Korean War in June 1950 and had recently converted from Mustangs to Gloster Meteor jet fighters.

77 Squadron conducted offensive sweeps up the Yalu River with USAF Sabres, bomber escort missions, and combat air patrols.

[12] Drummond was recommended for the US Air Medal for "courage, aggressiveness, tactical skill and devotion" in operations from 1 September to 28 October 1951.

[22] In April 1954 he was one of six navigators who made a graduation flight from East Sale in Victoria—home of the RAAF School of Air Navigation—to New Zealand in Avro Lincoln bombers.

[26] On 9 September, he married Margaret Buckham, a law clerk, in St Peter's Anglican Church, Newcastle; the couple had a son.

The nature of the work meant that, according to the official history of the post-war air force, "the FACs had probably the most hazardous job of any RAAF aircrew in the war".

[35] On the evening of 24 July 1966, having already flown that day, Drummond and his US pilot were called out to assist a company of soldiers besieged by Viet Cong troops.

Throughout the night and into the early hours of the next morning, in the face of heavy anti-aircraft fire, they marked enemy positions and directed air support until friendly troops arrived by helicopter to relieve the surrounded company.

[40] Recently returned to Williamtown following duty at Butterworth, Malaysia, the unit was to convert from Sabres to Dassault Mirage IIIO supersonic fighters.

[41] The court of inquiry into the accident investigated several possible explanations including engine problems, oxygen system failure, and pilot incapacity.

It noted that he was an above-average pilot with "exceptional leadership abilities" based on career assessments and evaluation by the USAF during his recent tour of duty in Vietnam.

In response, the medical officer opined that Drummond may have had a heart attack in the air, pointing out that a cardiovascular issue that was manageable on the ground could be exacerbated under flying conditions, and meant that the pilot would be unable to use his radio.

[44] Margaret Drummond, accompanied by the couple's son, was presented with the decoration at Government House, Canberra, in April the following year.