Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Situational Awareness; Distraction
Aircraft Equipment Problem Critical; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Aircraft; Human Factors
This was the second leg of a two leg evening. On final; ATC had asked us to maintain 250 KTS till glide slope intercept then slow to 180 KTS. The airplane was fairly light; 385;000 LBS. During the speed reduction; the airplane got a little above the profile/glide slope and Pilot Flying used vertical speed to re-intercept the glide slope. During this attempt to re-intercept the glide slope; we got busy performing other flight/checklist duties and failed to notice that the airplane had failed to capture the glide slope from above and descended 300 feet below the glide slope. (This was the second time this evening with this particular airplane that it failed to capture the glide slope on the first attempt). We immediately corrected back to intercept the glide slope and was fully captured on the glide slope by 2;400 MSL (2;200 AGL). We continued the landing to a very nice landing. ATC didn't mention the deviation to us at any time.  Failure to notice that the airplane hadn't captured the glide slope Do not get pre occupied with the checklists.
MD11 Captain reported the aircraft failed to capture the glideslope during approach to landing. Flight crew recovered and landed uneventfully.