Narrative:

On the river visual into dca we received a vgp [vertical glide path] unavailable message. I monitored the approach with LNAV & pth engaged; the aircraft became high and wasn't descending enough to keep up with the approach. I turned the automation off; but the aircraft was too high and fast for a stabilized approach so we executed a go around. The same thing happened on the second approach; however we were more prepared and I turned the automation off earlier and hand flew the rest of the approach.I'm not sure why we received the vgp unavailable message. This happened in my training during the ftd and once in the simulator. Neither the instructor nor the check airman knew the cause. I figured this was a sim issue and wouldn't be something I would see on the line. Obviously that's not the case; my only guess is that if you get vectored in tight that the aircraft won't allow an intercept in vgp. It was a good learning experience though; I've been able to think about how I would handle the situation again if it occurs again.I've asked a few other captains about the vgp unavailable and they mentioned they've seen it but don't know why it happens or how to fix it. I think it would be good to have some information available to the E-190 pilots as to why this occurs; and how to prevent it; also alternatives to use in the event that the aircraft is not able to use vgp. Obviously since this is strictly a visual approach (river visual) the alternatives are different than an RNAV or rnp. Or if this is a specific aircraft issue that would be good to know too. Because I've flown this approach before but never had the vgp unavailable message.

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Original NASA ASRS Text

Title: ERJ-190 flight crew reported executing a go-around following an unstabilized RNAV-F approach into DCA when 'VGP unavailable' was displayed.

Narrative: On the River Visual into DCA we received a VGP [Vertical Glide Path] unavailable message. I monitored the approach with LNAV & PTH engaged; the aircraft became high and wasn't descending enough to keep up with the approach. I turned the automation off; but the aircraft was too high and fast for a stabilized approach so we executed a go around. The same thing happened on the second approach; however we were more prepared and I turned the automation off earlier and hand flew the rest of the approach.I'm not sure why we received the VGP unavailable message. This happened in my training during the FTD and once in the simulator. Neither the instructor nor the Check Airman knew the cause. I figured this was a sim issue and wouldn't be something I would see on the line. Obviously that's not the case; my only guess is that if you get vectored in tight that the aircraft won't allow an intercept in VGP. It was a good learning experience though; I've been able to think about how I would handle the situation again if it occurs again.I've asked a few other Captains about the VGP unavailable and they mentioned they've seen it but don't know why it happens or how to fix it. I think it would be good to have some information available to the E-190 pilots as to why this occurs; and how to prevent it; also alternatives to use in the event that the aircraft is not able to use VGP. Obviously since this is strictly a visual approach (River visual) the alternatives are different than an RNAV or RNP. Or if this is a specific aircraft issue that would be good to know too. Because I've flown this approach before but never had the VGP unavailable message.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.