Date: 201707
Local time of day: 1801-2400
Location: ROA.Airport, VA
Flight conditions: VMC
Light: Night
Aircraft: Embraer Jet Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class C ROA
ATC / advisory: Tower ROA
Aircraft component: GPWS
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion; Distraction; Situational Awareness; Workload
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Automation Aircraft Terrain Warning; Person Flight Crew
When detected: In-flight
Result: General Maintenance Action
Contributing factors: Aircraft; Environment - Non Weather Related; Human Factors
Primary problem: Aircraft

Narrative: On a night visual approach to Runway 24 under VMC conditions; the GPWS issued an erroneous aural 'TERRAIN; TERRAIN' alert with associated Master Warning light at 1500 AGL when lowering the landing gear and above the RNAV flight path angle (lateral course indications were centered). Since we had building lights illuminating the ground below us; my MFD display on Terrain mode with no non-green terrain was displayed anywhere on the screen; we were above the FPA indications for the RNAV approach; and the alert was only momentary with no 'resolution' advisory (such as a 'pull up' or 'too low: gear' annunciation that would have identified the problem or suggested a solution); we continued our approach and had a normal landing. Given the lack of identifiable triggers for the alert; it was our conclusion that the system had malfunctioned and we wrote it up in the aircraft logbook. We both internally considered a go-around and rejected it after concluding we had multiple indications that there was no terrain between us and the runway (there was no time for discussion) and discussed the event after we were safely on the ground.Since I believe this was a system malfunction and there isn't anything directly related to put here; I think this is a good opportunity to raise the issue of the EXCEPTIONALLY dim terrain display on the MFD across the entire [Embraer] fleet. Regardless of the brightness level selected for the MFD; when TERR mode is used any displayed terrain is shown at a tiny fraction of the brightness of the rest of the display. During nighttime; as we were in this event; the pilot might see some terrain information displayed (in this case I saw areas of exceptionally dim green terrain displayed and those areas were not in our flight path); but during the day the terrain is so dim that it is entirely invisible even with the rest of the display at max brightness. It's clearly a software problem so is there any way that Maintenance can adjust the terrain brightness as a setting or can any pressure be put on Embraer/Honeywell for a patch to make the TERR display usable?




Synopsis: Embraer jet Captain reported that while above the RNAV flight path angle to ROA Runway 24; the GPWS erroneously alerted a single 'TERRAIN; TERRAIN' as the landing gear was lowered. The reporter also described the exceptionally dim MFD terrain display.