Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Confusion; Distraction; Situational Awareness; Human-Machine Interface
Deviation - Altitude Excursion From Assigned Altitude; Deviation - Altitude Crossing Restriction Not Met; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Flight Crew Returned To Clearance; Flight Crew Became Reoriented; Flight Crew FLC Overrode Automation
Human Factors; Aircraft
While descending via the LTOWN6 arrival landing north transition; the FMS was having difficulty complying with the 210 KTS at DASAC restriction. The speed had increased to 225 KTS. Distracted by the airspeed constraint; I noticed that we had descended below the 8;000 FT restriction at CLARK Intersection by 500 FT about a mile prior to CLARK. I brought this to the attention of the pilot flying and a correction was made to comply with the restriction.
The flight crew was forced to intervene manually when the autoflight system failed to meet the crossing restrictions at DASAC and CLARK on the LTOWN STAR to MEM.