Pilot reported lost comms during a formation flight.

Attributes
ACN	1721067
Time
Date	202001
Local Time Of Day	1801-2400
Place
Locale Reference	ZOA.ARTCC
State Reference	CA
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Military
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Communication Systems
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 28 Flight Crew Total 2800 Flight Crew Type 1000
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types Inflight Event / Encounter Weather / Turbulence

Narrative:

I was the wingman pilot of a section of [aircraft]. We were a standard formation until reaching ZZZ. Due to system issues; I did not have electronic means to measure my distance from the lead aircraft. The two primary electronic systems that we use; the air-air TACAN and datalink; were both inoperative. After departing ZZZ; I lost visual sight of the lead aircraft. Almost immediately following the lost sight event; my aircraft lost the ability to communicate to ATC; the lead aircraft; and with the other crew member in the cockpit. This lost comm event lasted approximately 3-5 minutes. The first priority was to ensure deconfliction from my lead aircraft; which I accomplished via lateral separation. This sequence of events led to us not maintaining standard formation and we got to about eight miles from the lead aircraft.after regaining communications; I requested a separate squawk code and clearance from ATC. Once I received my clearance; the deviation/event was complete.after a thorough debrief; one step that I should have accomplished was to squawk [priority] or lost comm. Either one of these codes would have kept ATC in the loop and they could have adjusted accordingly.

Original NASA ASRS Text

Title: Pilot reported lost comms during a formation flight.

Narrative: I was the wingman pilot of a section of [Aircraft]. We were a standard formation until reaching ZZZ. Due to system issues; I did not have electronic means to measure my distance from the lead aircraft. The two primary electronic systems that we use; the Air-Air TACAN and Datalink; were both inoperative. After departing ZZZ; I lost visual sight of the lead aircraft. Almost immediately following the lost sight event; my aircraft lost the ability to communicate to ATC; the lead aircraft; and with the other crew member in the cockpit. This lost comm event lasted approximately 3-5 minutes. The first priority was to ensure deconfliction from my lead aircraft; which I accomplished via lateral separation. This sequence of events led to us not maintaining standard formation and we got to about eight miles from the lead aircraft.After regaining communications; I requested a separate squawk code and clearance from ATC. Once I received my clearance; the deviation/event was complete.After a thorough debrief; one step that I should have accomplished was to squawk [priority] or lost comm. Either one of these codes would have kept ATC in the loop and they could have adjusted accordingly.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.