On September 17th 1943, two flights were flown into Cos to protect the airstrip at Antimachia complete with their 20mm Hispano LAA guns. The squadron had been so recently formed it had not had the opportunity to test fire the weapons. It was the first move of an LAA Squadron into action by air. The remainder of the Squadron arrived on the 17th and was split so it had 1 Flt in the ammunition dump and secondary landing ground at Lambia and the town of Cos itself (one flight) as well as the airstrip at Antimarchia.
Antimachia was built on a rocky plateau where digging in for protection was impossible. The guns themselves could not be depressed far enough to engage any enemy aircraft flying pop-up strikes from the valleys below. The Royal Artillery LAA unit awaiting its Bofors to arrived dubbed the Squadron’s position, “The VC guns”. The Squadron shot down 2 enemy aircraft on the 18th although it took casualties because of the rock splinters from the strafing attacks by Me-109’s.
The Squadron was attacked relentlessly every day by strike packages containing Heinkels, Me-109’s and Stukas. Casualties mounted because of the nature of the terrain and the air superiority held by the Luftwaffe. The Germans invaded on the morning of the 3rd of October 1943. Brandenburg Special Forces, Marines and Paratroop units of the Luftwaffe cut the island in half and mopped up at will.
The Squadron fought on until all its ammunition was exhausted and then they destroyed their guns and took up defence positions with the Durham Light Infantry, retreating to the hills when the DLI were beaten back. The last elements of the Squadron surrendered on the morning of the 8th October. Only 5 members of the squadron of 124 all ranks, left the island unwounded. The squadron effectively ceased to exist on that day and no formal disbandment has ever taken place. For their actions during this period, personnel of the squadron were awarded three Military Medals and seven Mentions in Dispatches.