To file a VFR (DC SFRA) flight plan to remain in the pattern at a non-towered airport, we suggest the following:
Enter the route on the Map view using the Route Editor beginning with the airport identifier. Then enter a latitude/longitude or fix radial distance point a few miles from the airport, finally add the airport identifier as your last point.
Set altitude to pattern altitude, although this won't matter. Most likely you will get an error "Cruise lower, short route." Ignore the error. Set your departure time as required. Use the 'Send To' icon to send the route to Flights. Tap proceed to file > You can adjust your time en route and any other parameters needed for filing.
Set the flight rules to VFR (DC SFRA). Enter the text 'Pattern Work' into Remarks. Then tap file. This will file your pattern flight plan.
You still need to obtain your squawk code from Potomac Approach before departure and follow the standard DC SFRA rules for flight in the pattern at a non-towered airport.
A VFR (DC SFRA) flight plan is not required if the tower is open. When the tower is closed, follow the instructions above for a Non-Towered Airport.