At the end of May 1944 "Nairana" sailed with the 15th Escort Group. On board was 835 Naval Air Squadron equipped with nine Swordfish and six Sea Hurricanes. The Swordfish patrolled day and night and some contacts were made on the ASV. All the contact come to nothing, it is now known the older model ASV in "Nairana"s Swordfish could be detected by receivers on board U-boats. In May they escorted convoys SL 157 (Freetown to United Kingdom) with MKS 48 (Mediterranean to United Kingdom) and the next group SL 158 with MKS 49. From 25 May the convoys were located by German Junkers Ju 290 reconnaissance aircraft. On the 25 and the morning of 26 May they were driven off undamaged but one Sea Hurricane failed to pull out of a dive killing the pilot. Later the same day another two Ju 290s appeared one was shot down and the other was probably shot down.