Question: The Indian Air Force's rank structure is based on that of the Royal Air Force, the highest rank attainable in the Indian Air Force is Marshal of the Indian Air Force, conferred by the President of India, MIAF Arjan Singh is the only officer to have achieved this rank, he was an Indian Air Force marshal who served as Chief of the Air Staff from 1964, to which year?

full_context: Document 1: Chief of the Air Staff (India): Chief of the Air Staff is the commander and the highest-ranking officer of the Indian Air Force. The position is abbreviated as CAS in the Indian Air Force cables & communication, and is usually held by a four-star officer of the rank Air Chief Marshal. The current CAS is Air Chief Marshal Birender Singh Dhanoa who took office on 31 December 2016, following the retirement of Air Chief Marshal Arup Raha.
Document 2: Gopal Gurunath Bewoor: General Gopal Gurunath Bewoor, Padma Bhushan, PVSM (11 August 1916 – 24 October 1989) was an officer of the Indian Army who served as the 9th Chief of Army Staff. In a long service spanning four decades, Gen. Bewoor saw action during World War II and later was involved in Indian Army operations during the 1965 as well as 1971 Indo-Pakistani war. He succeeded Field Marshal Sam Manekshaw as the Army chief in January 1973 and following his retirement from the army, served as the Indian Ambassador to Denmark till 1979. He was a recipient of the third highest Indian civilian honour of the Padma Bhushan.
Document 3: Bipin Rawat: General Bipin Rawat, UYSM, AVSM, YSM, SM, VSM, is the 27th Chief of Army Staff of the Indian Army. He assumed office on 31 December 2016 after retirement of General Dalbir Singh.
Document 4: Indian Army: The Indian Army is the land-based branch and the largest component of the Indian Armed Forces. The President of India is the Supreme Commander of the Indian Army, and it is commanded by the Chief of Army Staff (COAS), who is a four-star general. Two officers have been conferred with the rank of field marshal, a five-star rank, which is a ceremonial position of great honour. The Indian Army originated from the armies of the East India Company, which eventually became the British Indian Army, and the armies of the princely states, which finally became the national army after independence. The units and regiments of the Indian Army have diverse histories and have participated in a number of battles and campaigns across the world, earning a large number of battle and theatre honours before and after Independence.
Document 5: Subroto Mukerjee: Air Marshal Subroto Mukerjee, OBE (Bengali: সুব্রত মুখার্জী "Shubroto Mukharji") (5 March 1911 – 8 November 1960) was the first Chief of the Air Staff of the Indian Air Force (IAF). Born in a Bengali family of repute, he was educated in India as well as England. He joined the Royal Air Force and later was one of the first recruits of the Indian Air Force. He had an illustrious career and had been awarded with many honours until his accidental death in 1960. He has been called the "Father of the Indian Air Force".
Document 6: I. H. Latif: Air Chief Marshal Idris Hasan Latif (b.9 June 1923) was a chief of air staff of the Indian Air Force, having served as such from 1978 to 1981. After retirement, he has also served as the governor of the Indian state of Maharashtra (1982–85) and later as the Indian ambassador to France (till 1988). He was the first and only Indian Muslim to become the head of the Indian Air Force, or of any Indian armed force.
Document 7: Tapishwar Narain Raina: General Tapishwar Narain Raina Padma Bhushan, MVC (1921 – 19 May 1980) was a former Chief of the Army Staff of the Indian Army. He held the office between 1975 and 1978. Later, he served as High Commissioner to Canada. He was a recipient of the third highest civilian honour of India, the Padma Bhushan.
Document 8: Marshal of the Royal Air Force: Marshal of the Royal Air Force (MRAF) is the highest rank in the British Royal Air Force (RAF). In peacetime it was granted to RAF officers in the appointment of Chief of the Defence Staff (CDS), and to retired Chiefs of the Air Staff (CAS), who were promoted to it on their last day of service. While surviving marshals of the RAF retain the rank for life, the highest rank to which officers on active service are promoted is now air chief marshal. Although general promotions to Marshal of the Royal Air Force have been discontinued since the British defence cuts of the 1990s, further promotions to the rank may still be made in wartime, for members of the Royal Family and certain very senior RAF air officers in peacetime at the discretion of the monarch; all such promotions in peacetime are only honorary, however. In 2012, Charles, Prince of Wales was promoted to the rank while in 2014 Lord Stirrup, who had served as Chief of the Air Staff and Chief of the Defence Staff for over seven years, was also promoted.
Document 9: Air Force ranks and insignia of India: The Indian Air Force's rank structure is based on that of the Royal Air Force. The highest rank attainable in the Indian Air Force is Marshal of the Indian Air Force, conferred by the President of India after exceptional service during wartime. MIAF Arjan Singh is the only officer to have achieved this rank. The head of the Indian Air Force is the Chief of the Air Staff, who holds the rank of Air Chief Marshal. The current Chief of the Air Staff is Air Chief Marshal Birender Singh Dhanoa, appointed on 31 December 2016, following the retirement of Air Chief Marshal Arup Raha.
Document 10: Arjan Singh: Marshal of the Indian Air Force Arjan Singh, DFC (16 April 1919 – 16 September 2017) was an Indian Air Force marshal who served as Chief of the Air Staff from 1964 to 1969. For his distinguished service in commanding the IAF during the Indo-Pakistani War of 1965, he was awarded the Padma Vibhushan and in 1966 became the first IAF officer to be promoted to air chief marshal. After retiring from the IAF, he served as a diplomat, politician and advisor to the Indian government. He was Lieutenant Governor of Delhi from 1989 to 1990. In 2002, he became the first and only officer of the Indian Air Force to be promoted to five-star rank as Marshal of the Indian Air Force, equal to the army rank of Field Marshal.
Document 11: List of Royal Air Force air chief marshals: The following is a list of Royal Air Force air chief marshals. The rank of air chief marshal is a four-star officer rank and currently the highest rank to which RAF officers may be promoted to in a professional capacity. Throughout the history of the RAF there have been 140 RAF officers promoted to air chief marshal and at present two RAF officers hold the rank in an active capacity, namely the Chief of the Air Staff (the only dedicated RAF 4-star post) and the Chief of the Defence Staff (the only tri-service 4-star post currently occupied by an air chief marshal).
Document 12: Kodandera M. Cariappa: Field Marshal Kodandera "Kipper" Madappa Cariappa, OBE (28 January 1899 – 15 May 1993) was the first Indian commander-in-chief (C-in-C) of the Indian Army. He led Indian forces on the Western Front during the Indo-Pakistani War of 1947. He is one of only two Indian Army officers to hold the five-star rank of field marshal; the other being Field Marshal Sam Manekshaw. He was appointed commander-in-chief of the Indian Army in 1949.
Document 13: Field marshal (India): Field marshal (or field marshal, abbreviated as FM) ( , ) is a five–star general officer rank and the highest attainable rank in the Indian Army. Field marshal is ranked immediately above general, but not exercised in the regular army structure. It is a largely ceremonial or wartime rank, having been awarded only twice. A field marshal's insignia consists of the national emblem over a crossed baton and sabre in a lotus blossom wreath.
Document 14: Indian Air Force: The Indian Air Force (IAF; : "Bhāratīya Vāyu Senā") is the air arm of the Indian armed forces. Its complement of personnel and aircraft assets ranks fourth amongst the airforces of the world. Its primary mission is to secure Indian airspace and to conduct aerial warfare during armed conflict. It was officially established on 8 October 1932 as an auxiliary air force of the British Empire which honored India's aviation service during World War II with the prefix "Royal". After India gained independence from the United Kingdom in 1947, the name Royal Indian Air Force was kept and served in the name of Dominion of India. With the government's transition to a Republic in 1950, the prefix "Royal" was removed after only three years.
Document 15: Harbaksh Singh: Lieutenant General Harbaksh Singh, Padma Vibhushan, Padma Bhushan, VrC was a Three Star General in the Indian Army. As the Western Army Commander, Lt Gen Harbaksh Singh commanded the Indian Army forces and played a key role during the Indo-Pakistani War of 1965. He was awarded the Padma Vibhushan, Padma Bhushan and Vir Chakra.
ground_truth: 1969