Date: 201811
Local time of day: 0601-1200
Location: PCT.TRACON, VA
Flight conditions: IMC
Aircraft: EMB ERJ 140 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Descent
Airspace: Class D CHO; Class E PCT
ATC / advisory: TRACON PCT
Aircraft component: GPWS
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Confusion; Situational Awareness
Second reporter function: Pilot Flying; First Officer
Anomaly: Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Took Evasive Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: In solid IMC all the way to ILS minima. Approximately 10nm north east of CHO airport we were under positive control by Potomac Approach and being radar vectored for an ILS to Runway 03. At the time we were being vectored on an early right hand pattern downwind for the ILS. We were cleared on a heading and descent to 3000ft MSL.Aircraft configuration was clean; autopilot on and coupled to Heading and vertical speed. VS minus 1000ft Rate of Descent. I can't remember exact airspeed but from memory 200 knots and definitely less than 250knots. Correct local altimeter setting was set. Upon descending through approximately 3400ft MSL to 3000ft cleared by ATC we given a GPWS 'terrain; pull up' audio and matched display on the PFD. Immediately complied with the GPWS; initiated climb. As soon as the Pilot flying (FO) pitched nose up the GPWS warning disappeared.I contacted ATC immediately and informed them of the terrain warning and our actions/intentions. We leveled off at 4000ft and then continued to destination. ATC said that we were OK on original clearance based on their minimum vector altitudes and we shouldn't have received any GPWS warning. I told them that we were in IMC and were required to comply with any GPWS warning in those environmental conditions.Subsequently vectored to ILS 03 without further incident. No aircraft limitations were exceeded at any time throughout incident and recovery. Possible that the ATC minimum vector altitudes for that region have too tight margins given the terrain; and/or faulty or erroneous GPWS warning. Aircraft equipment appeared to be operating correctly without fault.Aircraft being operated at vertical speed of 1000ft/min ROD and normal airspeed range of 200-250kts to a cleared altitude and vector shouldn't have triggered a GPWS warning. I'm not sure what the actual cause for the GPWS was other than the closure to terrain. If the aircraft equipment hasn't has previous erroneous GPWS warnings and was working correctly; then the only thing I can think of is the ATC minimum vector altitude charts might need adjusting.


Second narrative: While descending towards CHO Potomac Approach gave us further descent from 5000 feet to 3000 feet. After passing 3;300 feet we received a GPWS warning for terrain. At this time we followed applicable company procedures spelled out in the QRH. Almost immediately after the initial pitch up the warning went away. While corrective actions were taking place the PM communicated with ATC about the GPWS warning and they insured us that 3000 feet was a good MVA for that area. ATC asked us for our intentions and we told them we would like to climb back up to 4000 feet. The GPWS warning happened when we were instructed to descend down to 3000 feet. Maybe reevaluate MVA around CHO.


Synopsis: EMB-140 flight crew reported a Ground Proximity Warning while descending to an altitude assigned by ATC.