Silsoe Sid and Brandnew,
Fine, perhaps you guys know better. My only qualification is that I have the type on my licence and flew them for some time in a foreign air force. The S-70 flight manual calls for two PILOTS, not one pilot plus an air crewman. The aircraft is more complicated than other smaller types such as Gazelle and Lynx.
The only time single pilot is normally authorised is during some types of ground runs, when the pilot sits in the left seat.