Date: 201706
Local time of day: 1201-1800
Location: PCT.TRACON, VA
Flight conditions: Mixed
Weather elements / visibility: 10
Light: Daylight
Aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class E PCT; Special Use P56
ATC / advisory: TRACON PCT
Aircraft component: Air/Ground Communication
Component problem: Improperly Operated
Reporter organization: Government
Reporter function: Approach
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Time Pressure; Workload; Communication Breakdown
Second reporter function: Pilot Not Flying; Captain
Anomaly: Airspace Violation All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural FAR
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Exited Penetrated Airspace; Flight Crew Returned To Clearance
Contributing factors: Procedure; Human Factors
Primary problem: Human Factors

Narrative: I asked if the instructor wanted to train; and that it was going to be a little busy. He said yes; I confirmed again that he was ok with it; and he agreed.  It probably was too busy for a newer trainee.  As the session progressed; I had another controller spin 2 aircraft for spacing.  They were basing around a 15 mile final which is very typical; and not overly busy.  I did check multiple times to ensure that the instructor was ok with the traffic; and he said yes.  The aircraft was being [vectored] for space and given a 090 heading; which is normal.  When the aircraft was issued the downwind heading he never answered.  He was hailed numerous times; and the surrounding positions checked their frequencies to make sure he wasn't there along with the tower.  The controllers went on the guard frequency with no response.  The NORDO aircraft then flew through P56A.  He eventually came back on the frequency on the other side of P56 and resumed being controlled to DCA.Aircraft should have a display of P56 within the cockpit so as to avoid it if they are NORDO or to question it if they believe they will enter it with the controller.


Second narrative: I was the Captain and Pilot Monitoring on (call sign) ZZZ to DCA. We were given the FRDMM RNAV Arrival landing 19 at DCA. From FRDMM intersection we departed the charted arrival on an assigned 140 degree heading and received multiple delay vectors; altitude and speed changes. Being handed off to the final POTOMAC Approach Controller; on 119.85 and checking in; we were given instructions to turn to a heading of 090 degrees; descend and maintain 7000' and speed 190 knots. I acknowledged the Controllers request and the Pilot Flying made the correct speed; altitude and heading corrections.Our position at this time; I approximated to be five to ten miles northwest of DCA. Weather conditions were ceilings 3000' broken to overcast; tops approximately 5000' and wind at 7000 ft was 220/25 knots. While we were on this heading the FO and I discussed the possibility of being vectored across the 19 Approach course and being vectored on the RNAV/Visual 19 form the east. Both the FO and I also discussed the unusual arrival track and how quiet the Approach Controller frequency had become. I had noticed earlier during the arrival phase the Controllers were experiencing periods of multiple radio transmissions and receptions followed by periods of long radio silences. At one point on the arrival I rechecked in with a Controller; because it was so 'eerily' quiet. I assumed it was one of those quiet periods. Continuing on the assigned 090 heading I heard a faint transmission on the number 2 COMM radio; which was tuned to guard 121.5 'call sign contact Approach Control on 119.85 and acknowledge with an ident.' Volume control was set to low on the number 2 radio as not to interfere with COMM number 1 transmissions. We then both looked down to see the number 1 radio was now tuned to 119.87. I immediately selected the corrected frequency; the FO hit the ident button and I reestablished communication with Potomac Approach on 119.85. The Controller gave us an immediate left turn to a northerly heading and informed us we had violated the P-56 prohibited airspace. So in a very short space of time we had unknowingly lost communications with Potomac Approach on 119.85 and due to the last assigned heading; given to us by the Controller; we had penetrated the P-56 airspace. We continued without any further incidents. If being vectored by the Controller and that heading/track; in the event of lost COMM; would put us in direct violation of any prohibited/restricted airspace; then the Controller should share with us his or her mental model of further vectors in order to keep us from violating airspace. In our case when the Controller issued the 090 heading; putting us on a direct course to enter the P-56 airspace; he could have followed up with 'you'll be on that heading for five miles; expect a northerly turn prior to the river.'  Have the data base include P-56 and have the icon display on the ND as to aide SA. Have the ability to use the ownship icon on arrival and approach plates. As Captain; PF; I should have been more acutely aware of possible lost COMM procedures and better SA; in the event ATC fails to provide approach vectors which would keep us clear of P-56.


Synopsis: An air carrier flight crew and PCT TRACON Controller described their respective actions when the aircraft became NORDO then flew through P-56 after one of the flight crew inadvertently changed the COM 1 frequency.