by poor working conditions and difficulties in communicating with General MacArthur's General Headquarters at Leyte. As part of the planning process each of Tarakan's hills was assigned a code name (for instance "Margy" and "Sykes"); during the Australian Army's campaigns in New Guinea geographic features had been named on an ad hoc basis, and it was hoped that selecting names prior to the battle would improve the precision of subsequent planning and communications. The Allied plans anticipated that Tarakan would be secured quickly. It was expected that the operation would involve a short fight for the airfield followed by a 'consolidation' phase during which the island's airfield and port would be developed to support Allied operations. The planners did not foresee significant fighting in Tarakan's interior, and no plans were developed for operations in areas other than the landing beaches, Tarakan Town and airfield. The planners did, however, correctly anticipate that the Japanese would make their main stand in an area other than the invasion beach and would not be capable of mounting a large counterattack. The Allied plans also expected that Tarakan would be transformed into a major base within days of the landing. Under the pre-invasion planning it was intended that a wing of fighter aircraft would be based at Tarakan six days after the landing and this force would be expanded to include an attack wing nine days later and staging facilities for a further four squadrons of aircraft within 21 days of the landing. It was also expected that the 26th Brigade Group and its supporting beach group would be ready to leave Tarakan by 21 May and the RAAF units could be redeployed in mid-June after providing support for the landing at Balikpapan. The Allied planners possessed detailed intelligence on Tarakan and its defenders. This intelligence had been gathered from a variety of sources which included signals intelligence, photographic reconnaissance flights and Dutch colonial officials. Tarakan was the Australian Services Reconnaissance Department's (SRD) first priority from November 1944. Prior to the invasion, I Corps requested that the SRD provide intelligence on Japanese positions in northern and central Tarakan. A five-man strong party landed on the island on the night of 25/26 April and successfully reconnoitered the defences on Tarakan's north coast, though the operative who was assigned to the centre of the island became lost and did not reach this area. The SRD operatives withdrew