MD-83
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Landed As Precaution; Flight Crew Diverted; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification; General Declared Emergency
Aircraft
After takeoff the First Officer and I lost the first and third windows of the Flight Mode Annunciations; both flight directors locked up and the autothrottle and autopilot would not engage. Both Digital Flight Guidance System 1 and 2 were tested. It was immediately obvious that we would not be able to navigate because the two Digital Flight Guidance systems were commanding different headings. I was concerned that I would also lose both Primary Flight Displays and their Primary Gyros. We declared an emergency; requested and received radar vectors hand flying back to our departure airfield with compass; altimeter and VSI for a landing. For the safety of my passengers; crew and I decided to land 5;000 LBS overweight rather than risk losing both primary flight gyros also. This was the second time in three days this happened to this aircraft.
After departure MD-83 crew declared an emergency due to Flight Guidance System issues; returned to the departure airport and landed overweight.