Operation Black Buck
Summary

Mission
Target
Date
Primary Vulcan
Reserve Vulcan
Notes
Black Buck 1
Port Stanley Airport runway
30 April–1 May
XM598 (Reeve)
XM607 (Withers)
Performed; primary aircraft cabin failed to pressurise shortly after takeoff, replaced by reserve
Black Buck 2
Port Stanley Airport runway
3–4 May
XM607 (Reeve)
XM598 (Montgomery)
Performed
Black Buck 3
Port Stanley Airport runway
13 May
XM607
XM612
Cancelled before takeoff due to weather conditions
Black Buck 4
Anti-aircraft radar
28 May
XM597 (McDougall)
XM598
Cancelled 5 hours into flight, due to a fault in the Victor fleet
Black Buck 5
Anti-aircraft radar
31 May
XM597 (McDougall)
XM598 (Montgomery)
Performed
Black Buck 6
Anti-aircraft radar
3 June
XM597 (McDougall)
XM598 (Montgomery)
Performed; primary aircraft forced to divert to Brazil due to a broken refuelling probe
Black Buck 7
Port Stanley Airport stores and aircraft
12 June
XM607 (Withers)
XM598 (Montgomery)
Performed

Question: What were the primary and reserve aircraft for the Black Buck 3 mission?
Answer: Vulcans XM607 and XM612 were designated the primary and reserve aircraft, respectively.