Widebody; Low Wing; 2 Turbojet Eng
Flight Crew Last 90 Days 56; Flight Crew Total 13500; Flight Crew Type 2900
Confusion; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert
Aircraft; Procedure
Departing ATL Runway 26L on CADIT 7 departure to MPASS. We turned the autopilot on at 1;000 FT with Profile and NAV selected and began slat retraction 10 K after reaching S speed. After the turn to 300 degrees RNAV to MPASS; ATC told us to delete the 250 KT speed restriction at ZOLAN. After deleting the speed the aircraft automation turned the aircraft inside of MPASS. ATC advised us that 'in the future deleting the speed restriction at ZOLAN does not mean go direct to ZOLAN.' We indicated that the automation was flying the departure and we showed us .1 mile left of course. He indicated we were well right of course.  The FMC logic apparently does not understand flying over a point after deleting a speed. We recommend not deleting a speed until passing MPASS. A contributing factor may have been changing the clean up altitude to 1;500 FT instead of 3;000 FT. At 1;500 FT we are closer to the airport and to S+10 much sooner.
ATC deleted the ZOLAN 250 KTS restriction prior to MPASS on the ATL Runway 26L CADIT 7 MPASS transition and after doing so; an air carrier's FMS turned the aircraft precede direct ZOLAN.