Special Operations Aircraft (SOA). 26 converted from CH-47C with similar capabilities as the
MH-47D but with the
CH-47SD (Super-D) increased fuel capacity and upgraded avionics including sophisticated terrain following radar. All assigned to the
Nightstalkers Battalion of the 160th Aviation Regiment (SOAR) at Fort Campbell, Kentucky.
In 1988 the Chinook was equipped with their first air-to-air refueling (AAR) system.
Replaced by the
MH-47G variant.
In 1995, the British Royal Air Force
ordered eight of the roughly similar
HC.3. They were delivered in 2001 but never entered operational service due to technical issues with their unique avionics fit. In 2008, work started to downgrade the HC3s to HC2 standard, to enable them to enter service.
US Army Aviation 
Royal Air Force 