Narrative:

On the lda DME to runway 19 at dca. The first officer was flying and was looking at the navigation display distance to the next waypoint instead of the DME and began his descent to 1600 ft at 9.5 DME. He leveled at 1600 ft at 8.5 DME and the tower called with a low altitude warning at which time we both realized that we had gone below the procedure altitude. I did not catch his mistake and should have.

Google
 

Original NASA ASRS Text

Title: MD80 FLT CREW DESCENDS EARLY TO 1600 FEET ON THE LDA DME RWY 19 AT DCA. TOWER CALLS WITH LOW ALTITUDE ALERT BUT CANNOT ACT BEFORE 1600 FEET IS THE CORRECT ALTITUDE.

Narrative: ON THE LDA DME TO RWY 19 AT DCA. THE FO WAS FLYING AND WAS LOOKING AT THE NAV DISPLAY DISTANCE TO THE NEXT WAYPOINT INSTEAD OF THE DME AND BEGAN HIS DSCNT TO 1600 FT AT 9.5 DME. HE LEVELED AT 1600 FT AT 8.5 DME AND THE TWR CALLED WITH A LOW ALT WARNING AT WHICH TIME WE BOTH REALIZED THAT WE HAD GONE BELOW THE PROC ALT. I DID NOT CATCH HIS MISTAKE AND SHOULD HAVE.

Data retrieved from NASA's ASRS site as of January 2009 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.