The Puma has provided outstanding service to the RAF. It first came on strength in 1971, and has since seen use in the vast majority of operational theatres in which the British military has been engaged. It is a medium battlefield helicopter that undertakes the tactical movement of troops (as many as 12 with full equipment) and loads (of up to two tonnes), casualty evacuation and other roles and serves with Nos 33 and 230 Squadrons at RAF Benson. An upgrade programme is under way which sees 24 examples of the existing Puma HC1 being converted to HC2 standard. The effort increases the type's speed and range, provides it with new avionics, and adds numerous further enhancements.