Date: 201409
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Aircraft: Regional Jet 200 ER/LR (CRJ200)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class E ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: Turbine Engine Thrust Reverser
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Human factors: Confusion
Second reporter function: Pilot Flying; Captain
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Person Flight Crew
When detected: In-flight
Result: Aircraft Aircraft Damaged; Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Declared Emergency
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: On climb out at approx 13;000 feet and 310 knots heard a thud and the aircraft rolled slightly left. Captain disconnected autopilot and stated we had a control issue and we should declare an emergency. We were approx 50 miles north of [our departure] and so elected to declare an emergency and return. I checked hydraulics; flight control indications and pressurization and everything appeared normal except for a slight amount of left aileron trim being required for level flight. The handling issue got significantly better as we slowed so we suspected structural damage. As we returned we discussed possible scenarios involving aircraft handling deteriorating as we slowed for landing and how we may handle it. We were initially assigned [the left runway] but requested [the right] due to its longer length. I briefed the flight attendant as per [company SOPs] and informed her to expect a normal landing. As we slowed to 200 knots handling returned to normal and we landed normally. Upon post flight inspection; there was a large section of the thrust reverser that had been ripped off.


Second narrative: During climb out at approximately 13;000 feet and 310 knots we heard a thud and the aircraft rolled slightly to the left. I disconnected the autopilot and stated; 'we have control issue and need to declare an emergency.' We were approximately 50 miles north of [the airport] and elected to declare an emergency and return. I told the FO to check the hydraulics; flight control indications; and pressurization and everything appeared normal except for a slight amount of left aileron trim required for level flight. The FO called the FA; dispatch and operations to let them know we were returning. The FO told the FA we were a Emergency. The handling issue got significantly better as we slowed. We suspected structural damage. As we returned; we discussed possible scenario's involving aircraft handling deteriorating as we slowed for landing and how we may handle it. We were initially assigned [the left runway] but requested [the right] due to it's longer length. Upon post flight inspection; the entire bottom half of the left engine thrust reverser section had been ripped off. We deplaned the passengers and apologized for the inconvenience. We took pictures of the damage; and filled out paper work. Operations told us we have another plane and we could start boarding.


Synopsis: CRJ200 flight crew reported hearing a thud passing 13;000 FT. As the aircraft rolled slightly to the left the Captain corrected with aileron. An emergency is declared and the flight returns to the departure airport; where post flight inspection reveals a large section of the thrust reverser has been ripped off