Date: 201907
Local time of day: 0601-1200
Location: DCA.Airport, DC
Flight conditions: VMC
Light: Daylight
Aircraft: Regional Jet 700 ER/LR (CRJ700)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Airspace: Class B DCA
ATC / advisory: Tower DCA
Second aircraft: Large Transport
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Situational Awareness
Anomaly: ATC Issue All Types; Ground Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Wake Vortex Encounter; Inflight Event / Encounter Loss Of Aircraft Control
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Regained Aircraft Control
Contributing factors: Environment - Non Weather Related; Procedure
Primary problem: Environment - Non Weather Related

Narrative: We were departing DCA Runway 1; properly set up and ready to hit NAV mode between 150-200 feet with heading bug set to correct position. Tower asked if we have the departing aircraft in sight. It was still on the runway. I believe it was an A321; but it could have been a 737. Obviously; because it was still on the runway; the FO (First Officer) said yes. He then cleared us for takeoff. I immediately hit the 'Continuous Ignition' in case of the possibility [of a wake encounter]; not because I expected it. At about 100 feet AGL we hit wake turbulence and the aircraft flipped right wing down. The First Officer immediately turned the ailerons full left. The First Officer had no more aileron to use and aircraft continued to rotate right wing down. We were at departure speed; flaps 8; and 160 knots. For those few seconds we had lost control of the aircraft. Our immediate objective was to recover wings level. We gained control back but were headed directly for P56. When we regained control; I quickly looked down outside and we were able to turn and remain on our correct path over the river and clear of P56. We were instructed to contact Departure. I then told the Tower we hit wake turbulence. 'I have the aircraft in front of us and his wake turbulence.' We proceeded up the river and got more wake turbulence. I asked for a heading to get out of the wake turbulence from Departure. Initially he said he couldn't give it to us. The FO suggested to climb out of it. I said no; we need to increase our speed to get more aileron control. As soon as we cleared the northern edge of P56 we were given a heading to depart the wake of the aircraft we were following. No further incident.The Tower Controller was in a rush. There were approximately 4-6 aircraft in line for departure with aircraft also landing the same runway. We were given a takeoff clearance too close to the other departing aircraft. I was an Air Traffic Control Tower Operator in the 80's. We used to have time separation for departures that seems to have has disappeared. I should not have accepted a takeoff clearance that close to a departing aircraft. It is a thought that I'd rather have distance behind me that I can't see; and accept a shorter distance in front of me that I can see.I have a few suggestions that I believe should be put in place immediately. There should be at least one minute between departures at all airports. This matter is further compounded especially in DCA where encroachment of P56 is a probable outcome. We shouldn't make something a standard practice that has a high possibility of a negative outcome. We should not accept departure behind aircraft that are less than one minute in front of us. Low speed; low altitude wake turbulence recovery should be taught and covered in the sims. This is a very serious safety and security matter.




Synopsis: CRJ-700 Captain reported a wake turbulence encounter departing DCA that resulted in loss of roll control for several seconds at low altitude just after takeoff. Reporter suggested a minimum of one minute separation between aircraft on departure.