Air carrier flight crew reported the lights at DCA's Runway 15 were too bright; causing distractions on approach to Runway 19.
Synopsis
Air carrier flight crew reported the lights at DCA's Runway 15 were too bright; causing distractions on approach to Runway 19.
Narrative
On short final to Runway 19; on the River Visual Approach; backed up by the RNAV (GPS); I was pilot monitoring. After completing configuration and landing checklist; I looked up to check the VASI indication. What I saw were four; bright white lights and also the lights for Runway 15 which were all on full bright. What confused me was that I could not see any other VASI that should have been the offset VASI for 19. Confused by not seeing any other VASI; and aware we were very close to the final turn; I instinctively called out to the PF; You're high."In response; he immediately started a downward 'correction;' but then hesitated and said something to the effect "that can't be right;" at which point; I looked down at the VNAV glidepath and saw that it was quickly trending low. As I looked back up to again check the VASI; I now finally made out the actual; much dimmer; offset VASI for 19 which showed three red and one white. Immediately after this; the Tower called with a low altitude alert. However; the PF had already started to correct back to the correct glidepath and accordingly; no further action was warranted since we [were] completely VMC; over the river; with all potential obstacles well in sight and clear.In debrief; we both expressed surprise that a VASI indication of three red and a white would have set off a low altitude alert.Cause: Runway 15 lights were on full bright; even though that runway was not in use; at least not for landing; whereas the lights for the active Runway 19; were dimmed to the point that they were being overpowered by the much brighter lights of the inactive runway. Contributing factors was the high-workload environment on short final for the River Visual Approach at night.Suggestions: If a runway is not in use; particularly when it's close in angle to the actual; active runway; its lights should; at the very least; not be any brighter than those of the active runway! Even though 15 may have been in use for takeoff; that should not require the lights be full bright; far from it!"
Second reporter narrative
On short final to Runway 19; on the River Visual Approach; backed up by the RNAV (GPS); I was pilot flying. After completing configuration and landing checklist; I looked up to check the VASI indication. What I saw were four; bright white lights and also the lights for Runway 15 which were all on full bright. What confused me was that I could not see any other VASI that should have been the offset VASI for 19. Confused by not seeing any other VASI; and aware we were very close to the final turn; I heard the call from the PM; You're high."In response; I immediately started a downward 'correction;' but I hesitated and said to the effect "that can't be right;" at which point; he looked down at the VNAV glidepath and saw that it was quickly trending low. Then going back to looking towards the actual; much dimmer; offset VASI for 19 which showed three red and one white. Immediately after this; the Tower called with a low altitude alert. However; I (PF) had already started to correct back to the correct glidepath; and accordingly; no further action was warranted; since we were completely VMC; over the river; with all potential obstacles well in sight and clear. In debrief; we both expressed surprise that a VASI indication of three red and a white would have set off a low altitude alert.Cause: Runway 15 lights were on full bright; even though that runway was not in use; at least not for landing; whereas the lights for the active Runway 19 were dimmed to the point that they were being overpowered by the much brighter lights of the inactive runway. Contributing factor was the high-workload environment on short final for the River Visual Approach at night. The river not being lit up and able to be seen more at night.Suggestions: If a runway is not in use; particularly when it's close in angle to the actual; active runway; its lights should at the very least; not be any brighter than those of the active runway. Even though 15 may have been in use for takeoff; that should not require the lights be full bright; far from it! Make it RNAV only at night or allow the river to be lit up like a path to follow so you're not fighting to find the river and fly the airplane in a highly [congested] area."
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.