Both DGNSS units and the Fanbeam failed within a fifteen-minute window — an unusually fast and broad failure pattern. What should this pattern make the DPO and Master suspect?

A. The failure pattern is irrelevant once all references have recovered

B. This pattern only matters for the annual DP trial, not for the immediate operational decision

C. A common-cause failure rather than three independent coincidental faults — possibilities include a GNSS-wide issue (satellite outage, ionospheric disturbance, jamming/spoofing), a shared power supply fault, or an environmental factor (the squall) affecting multiple systems simultaneously; this should be investigated before assuming normal operations can resume

D. Nothing unusual — reference systems commonly fail in clusters with no underlying common cause worth investigating

A. Immediately switch to manual joystick control regardless of the remaining references' status

B. Ignore the dropout since two references remain — no action is required

C. Restart the DGNSS 1 receiver immediately without checking the current position solution first

D. Confirm the DP system has automatically excluded DGNSS 1 from the position solution and is now running on the two remaining references (DGNSS 2 and Fanbeam); verify the resulting position solution is stable before doing anything else

A. Increase monitoring vigilance specifically — with only two references, there is no longer a "voting" majority if one of the remaining two starts to disagree, so any divergence between DGNSS 2 and Fanbeam now requires immediate judgement rather than automatic resolution; the DPO should also consider what reference would be left if either of these also fails

B. Nothing changes — two references is operationally identical to three for monitoring purposes

C. Immediately suspend operations regardless of how the two remaining references agree

D. Disable the alarm system since fewer references means fewer expected alarms