over whose requirements had precedence, McNamara intervened in 1961, declaring that the Air Force desires would override suggestions by the Navy. The F-111A variant first flew on 21 December 1964 from Carswell AFB, Texas. It was followed by the F-111B, which first flew on 18 May 1965. As F-111 development continued, stall issues arose in certain parts of the flight regime; these were addressed by modifying the engine inlet in 1965–66, ending with the "Triple Plow I" and "Triple Plow II" designs. The F-111B was cancelled by the Navy in 1968 due to weight and performance deficiencies. The improved F-111E, F-111D, F-111F models were subsequently developed for the USAF. The FB-111A strategic bomber and the EF-111 electronic warfare versions were also later developed for the USAF. Production ended in 1976, with a total of 563 F-111s of all variants built, well below the prediction of 1,500. Replacing the Canberra The Menzies government first publicly discussed the need for replacing the English Electric Canberra in 1954, only a year after the RAAF began receiving the bomber. The non-supersonic Canberra lacked radar and electronic countermeasures, all disadvantages based on Korean War experience. The RAAF believed that it needed a new strategic bomber to fulfill the nation's obligations to the Commonwealth Strategic Reserve in Malaysia, ANZUS, and SEATO. Air Staff Requirement 36 that year mandated an all-weather attack aircraft by 1959 capable of delivering a variety of bombs and missiles. A study recommended one of the British V bombers, but Prime Minister Robert Menzies' Minister of Defence Frederick Shedden decided in 1956 that at £1 million each they were too expensive. Air Marshal Valston Hancock, Chief of the Air Staff, stated in April 1960 that Australia needed a replacement for the Canberra. Although in mid-1962 the Menzies government again decided to not replace the Canberra, Indonesia's increasingly aggressive statements regarding Malaysia soon caused Australia to reevaluate the decision. The Sydney Morning Herald reported in October 1962 that the Indonesian Air Force's Soviet Tupolev Tu-16 bombers could reach Sydney or any other Australian city with a light bomb load, while the Canberras could not fly in all weather and had a range of , insufficient to reach Jakarta. The opposition Labor Party, led by Arthur Calwell, used the report to criticize Menzies. The government denied that the Tu-16 could reach Sydney, but Minister for Air Frederick Osborne acknowledged that the Canberras were "the weakest