formation flights
One thing to remember a controller may have the lead acft squawk and also the trail aircraft of a non-standard formation. This is to assist him in separating the formation. I have done this only twice in 16 years of mixed ATC experience, Approach and Center as most flights are of a standard formation.
This is an para in FAAO 7110.65
-5-8. ADDITIONAL SEPARATION FOR FORMATION FLIGHTS
Because of the distance allowed between formation aircraft and lead aircraft, additional separation is necessary to ensure the periphery of the formation is adequately separated from other aircraft, adjacent airspace, or obstructions. Provide supplemental separation for formation flights as follows:
a. Separate a standard formation flight by adding 1 mile to the appropriate radar separation minima.
REFERENCE-
FAAO JO 7110.65, Para 2-1-13, Formation Flights.
FAAO JO 7110.65, Para 5-5-1, Application.
FAAO JO 7110.65, Para 7-7-3, Separation.
P/CG Term- Formation Flight.
b. Separate two standard formation flights from each other by adding 2 miles to the appropriate separation minima.
c. Separate a nonstandard formation flight by applying the appropriate separation minima to the perimeter of the airspace encompassing the nonstandard formation or from the outermost aircraft of the nonstandard formation whichever applies.
d. If necessary for separation between a nonstandard formation and other aircraft, assign an appropriate beacon code to each aircraft in the formation or to the first and last aircraft inātrail.
NOTE-
The additional separation provided in para 5-5-8, Additional Separation for Formation Flights, is not normally added to wake turbulence separation when a formation is following a heavier aircraft since none of the formation aircraft are likely to be closer to the heavier aircraft than the lead aircraft (to which the prescribed wake turbulence separation has been applied).
REFERENCE-
FAAO JO 7110.65, Para 9-2-12, Military Aerial Refueling.