Air carrier flight crew received a terrain alert on a visual approach to Runway 33 at BGR; and suggested it may have been a false alert.
Synopsis
Air carrier flight crew received a terrain alert on a visual approach to Runway 33 at BGR; and suggested it may have been a false alert.
Narrative
We were being vectored for the visual for RWY 33. As we were approaching ELSUH; which was our last cleared waypoint; ATC vectors us on a right turn for an extended left downwind and asks us to descend and maintain 3000. ATC then turns us for a left base and asks us to descend and maintain 2500. At this point ATC asks us if we have the airport in sight which we didn't; so they then point out our traffic to follow which we did have in sight. We were cleared for the approach and vectored ourselves to intercept the localizer right before ELSUH. Everything is normal and we intercept the localizer. Once we were between ELSUH and CUVOT; we received a ground proximity warning and proceeded to escape. The warning went away fairly quickly as soon as we began our climb and at this point we asked ATC for a level off altitude and to be vectored back around. We were at 2500 ft when we received the warning. The rest of the flight was uneventful.Cause: There is a little mountain on final for RWY 33 and when we were being vectored back around; ATC told us that they have had other aircraft experience this before and that they believe that when there is snow and ice on the ground and especially on that mountain; which were the conditions for that night; it can possibly give false alarms to the computers. Another cause can simply be a false alarm with the aircraft because we were never in any situation where we were that close to terrain.Suggestion: Continue to always monitor altitudes and proper terrain clearance and proper escape maneuvers in the event of a warning.
Second reporter narrative
We were given vectors to extend our downwind to come in behind another aircraft for the visual runway 33 backed up by the ILS 33 at 3000 feet. Once we had the traffic we were following in sight; we were asked to descend to 2500 outside ELSUH. Once established on the localizer we crossed ELSUH; and well before CUVOT; we received a Terrain warning and executed an escape maneuver from 2500 feet. We asked ATC for an altitude and vectors back around without incident.Cause: The controller acknowledged there have been other terrain warnings on this approach due to ice and snow on a hill below the approach. There is a 1346 foot obstacle on this approach which was the trigger for the alert. Suggestion: Do not accept vectors below 3000 feet on a visual approach into runway 33 at BGR.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.