Date: 201912
Local time of day: 0601-1200
Location: PCT.TRACON, VA
Flight conditions: IMC
Light: Daylight
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class D CHO
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Confusion
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Conflict Airborne Conflict; Inflight Event / Encounter CFTT / CFIT
Detector: Automation Aircraft Terrain Warning; Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: I was Pilot Flying and the FO (First Officer) was Pilot Monitoring. We were receiving vectors from Potomac Approach into Charlottesville. We were downwind from Runway 3 at 3;000 feet. We received a terrain warning passing over an obstacle chartered at 1;795 feet.While receiving vectors; we briefly passed over the obstacle of 1;795 ft at 3;000 feet. The aircraft terrain warning sounded once. We were not yet configured to land and were at a lower power setting. We both noticed that immediately after the warning had occurred; our RA was briefly at 1;160 feet.On vectors from Potomac Approach; we passed over the obstacle of 1;795 feet at 3;000 feet. We had briefed the obstacle on the approach plate prior to beginning our descent into Charlottesville. We were at a lower thrust setting because we were in level flight; receiving radar vectors; and not yet configured for the approach. We received the terrain warning and it stopped almost as soon as it had occurred; after one warning. I was preparing to respond; but it subsided before I could react to the condition. We both noticed that right after the warning; that our RA was briefly at 1;160 feet.I heard the terrain warning and I was in the process of beginning to perform the terrain escape maneuver per the AOM 1; by disengaging the autopilot and following the profile; however; the warning had stopped. The warning was very brief and only alarmed once. I noticed that when I was going to disconnect the autopilot and the warning had stopped; that our RA was briefly at 1;160 feet. We were both aware of the obstacle through the briefing of the approach chart and were above our MSA for our sector. We maintained 3;000 feet; contacted approach to make sure we had the correct altimeter setting of 30.24 and that we were showing level at 3;000 feet. The Controller confirmed that the altimeter setting of 30.24 was correct and that we were level at 3;000 feet. The crew was completely situationally aware of all obstacles and terrain in the area.Possibly quicker to respond to a terrain warning upon hearing the initial warning.


Second narrative: Captain pilot flying and First Officer pilot monitoring. Vectors by Potomac approach on downwind for Runway 3 abeam airport 3;000 feet into Charlottesville. Terrain Warning over top obstacle of 1;795 feet.Passed briefly over obstacle of 1;795 feet; setting our RA to 1160. We knew we were over top of that briefed obstacle at that time and altitudes. We were not configured to land yet and thrust was reduced for speed. Terrain warning sounded once.Passed over obstacle of 1;795 feet (briefed on chart); RA showed 1160. We were not configured to land yet and thrust was reduced for speed. Terrain warning. Confirmed altitude and altimeter setting with Potomac Approach. Warning stopped after one warning before response was made.About to perform terrain escape maneuver and as autopilot was to be disconnected and thrust forward; warning stopped. RA showed 1160 briefly and stopped. We were aware of the obstacle. Highest MSA in our sector was 2;000 feet. Maintained 3;000 feet and contacted approach. Crew was situationally aware of obstacles and terrain. To be quicker to respond to terrain warning on first warning.


Synopsis: EMB-145 flight crew reported a terrain warning while flying over an antennae at ATC assigned safe altitude.