Complex sentence: On 4 May two aircraft lost the convoy in heavy weather and requested a homing beacon from "Avenger", who was unable to help not having the correct equipment, and both aircraft and crews were reported missing.
Split into simpler sentences: On 4 May two aircraft lost the convoy in heavy weather and requested a homing beacon from "Avenger". Who was unable to help due to not having the correct equipment, and both aircraft and crews were reported missing.