I agree with Max Angle’s professional approach, but be aware of possible problems; I have posted this reply in an earlier thread:
My experience of two captains flying together comes from two different sectors of the industry, both indicated hazards. First, in a non-public transport operation, pilots flew as Capt / Co-Capt with command rotating on each leg. With a small group of pilots the procedures were standardized (if not always written down) and personal interaction was both strong and balanced. However many slips and mistakes were made, most were quickly caught and corrected, but complacency and failure to behave as a NFP led to a few interesting events.
My second experience is from investigating incidents and accidents. I have seen evidence that two Captains on the flight deck significantly increase the risk of an incident. Even worst three captains, whether or not the jump seat pilot was in official or unofficial capacity (a caution here for check flights and LOSA, but of course everyone is flying ‘by the book’ on these sectors).
The evidence indicated that a RHS Captain NFP was not a good monitor, this also applied to a lesser extent to training captains during instructional or check flights. A Captain monitoring another Captain intervened much later than would have occurred with a recently qualified First Officer. Some pilots did not intervene at all. The reason for this appeared to be the assumption by the NFP that the handing pilot knew what he was doing, or at least as long as the monitoring pilot knew what was happening from his perspective he assumed that he did not have to alert the Commander.
With two Captains, their joint ability to detect threats and hazards appeared lower than with a normal crew; thus during an event they were at higher risk before recovery action was commenced. I wonder if this is similar to group risk theory; where a decision taken by a group of people tends to be more risky than when taken by an individual. Although CRM encourages group participation, the responsibility for any decision still rests with the commander. With a level authority gradient of two Captains they may operate more as a group, whereas a more balanced authority gradient with a captain and first officer maintains greater respect for the commander and his decisions.
Another aspect of incidents and accidents with two captains was that the RHS monitoring captain was not always familiar with the duties of that role, particularly in the use of standard procedures and the physical actions from the right seat.