Flight of two, IFR

"Dave S" wrote...
Im sure the military does it all the time..

However.. practically.. WHO is going to be responsible for separation on
a formation flight if it goes IMC? The military has procedures that
address this.. i am curious to know if the US civil sector does, and
I've not seen anything pertaining to it..

Anyone care to expand on the DETAILS of actually doing a formation under
IFR in IMC or VMC?

Indeed, the military has numerous procedures that address IFR flight in
formations. I'm sure the Army, Navy, and Air Force have their own specific
procedures, but in general:

It begins with dedicated VMC formation flying practice early in training,
then expands to IFR/IMC formation procedures. In an IFR formation, the flight
is treated by ATC as a single airplane. Responsibility for separation between
the separate elements in the flight is on the formation leader.

It is possible and permissible to fly an approach and landing in formation
with tactical (small) aircraft. Generally, IFR formation landings are limited to
2 airplanes, and approach minimums may be higher than those for single aircraft.

When weather is below formation approach & landing minimums, the flight will
separate into 2 single-aircraft flights prior to the approach. It is
essentially the same as one of the airplanes asking for a "popup" IFR clearance.
The flight remains together (either enroute or in holding) until the separate
clearances are obtained. Then the second aircraft starts squawking his own
discrete code and follows his own clearance with regard to altitude and route.

I don't know if there are separate civil procedures; the concept should be the
same. However, I don't know how the FAA looks on intentional civil IFR/IMC
formation flight in the first place, especially with regard to FAR 91.13...