of the USAAF P-40 pilots remained airborne throughout the first attack, 1st Lieutenant Robert Oestreicher, who has also been credited by US and Japanese sources with one Aichi shot down and one damaged. Toyoshima's Zero is considered to have been brought down by small arms fire from Sappers Tom Lamb and Len O'Shea of the 19th Battalion. Most aviation historians believe Tsuru and Uchikado's Aichi was brought down by ground fire, possibly from a major Australian Army camp at Winnellie. Egawa reported that the damage to his Zero came from hitting a tree at Darwin. Second raid The second wave, made up of 54 land-based medium bombers (27 Mitsubishi G3M and 27 Mitsubishi G4M) arrived over Darwin just before midday. The town's air raid sirens were sounded at 11:58 am when the bombers were sighted. The Japanese force separated into two groups flying at . One of these formations attacked RAAF Base Darwin from the south-west while the other approached from the north-east. The two formations arrived over the base at the same time, and dropped their bombs simultaneously. The Japanese bombers then turned, and made a second attack on the base. Due to defective fuses, the Australian heavy anti-aircraft flak gunners were unable to shoot down or damage any of the high-flying Japanese aircraft. The bombers left the Darwin area at about 12:20 pm. This raid inflicted extensive damage on the RAAF base, though casualties were light. Of the RAAF aircraft at the base, six Hudson light bombers were destroyed and another Hudson and a Wirraway were badly damaged. Two American P-40s and a B-24 Liberator bomber were also destroyed. Six RAAF personnel were killed. Lewis and Ingman list 30 aircraft destroyed. The Japanese carrier force launched a small number of D3A dive bombers during the afternoon of 19 February to attack the Florence D. and Don Isidro. Don Isidro was the first of these two ships to be attacked, and was rapidly sunk north of Melville Island. Eleven of her 84-strong crew were killed. The dive bombers also attacked Florence D. and sank her off Bathurst Island with the loss of four crewmen. All of the survivors from Don Isidro were rescued by the corvette on 20 February. Some of Florence D.s survivors landed on Bathurst and Melville Islands while the remainder were rescued by Warrnambool on 23 February. Among the survivors of Florence D. were the rescued