Flight Crew Last 90 Days 192
Situational Awareness
Inflight Event / Encounter CFTT / CFIT
General None Reported / Taken
ATC Equipment / Nav Facility / Buildings; Aircraft; Human Factors
Were cleared for ILS 31R and asked to maintain 170 to DATLE. Outside of DATLE; autopilot captured glideslope. After passing DATLE; I called for flaps 30 then 40. At approximately 2000 FT MSL the glide slope oscillated vertically (as if departing aircraft crossed critical area) and the autopilot increased our rate of descent. Shortly after this we received the GPWS caution 'Caution Obstacle'. I disconnected autopilot and slowed our descent rate. At this time we were visual and made a normal landing in the touchdown zone. With a heavy aircraft and a slight tailwind on final; our rate of descent contributed to the GPWS caution. Having flown this approach before it was disconcerting to receive this caution while stabilized on the Localizer and glideslope with the autopilot coupled. With the tailwind we should not have accepted the 170 knots to DATLE; which would have allowed us to fully configure prior to DATLE.
Air carrier First Officer experiences an EGPWS 'caution obstacle' during a coupled ILS approach to Runway 31R at DAL. The glideslope had oscillated up then down and the autopilot followed the glideslope; triggering the caution. The autopilot was disengaged and the approach continued to landing.