Date: 201909
Local time of day: 1201-1800
Location: ZZZZ.Airport, FO
Flight conditions: IMC
Weather elements / visibility: Cloudy; Rain; Turbulence
Light: Daylight
Aircraft: MD-11
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Takeoff / Launch
Airspace: Class B ZZZ
Aircraft component: Autoflight System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Relief Pilot
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Speed All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Executed Go Around / Missed Approach; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport; General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Taxiing out to gate Captain had issues with his FD (Flight Director). Captain placed his FD source to #2. All appeared well. Normal takeoff until 400 ft. At 400 ft. the Captain commanded NAV proformance. I selected NAV and PROF from the GCP. Shortly afterwards the Captain asked for Autoflight. When pressing Autoflight the AP2 annuncated in the FMA. I pressed Autoflight again but AP2 remained enunciated. I mentioned this to the Captain. ATC then cleared us to fix ZZZZZ and I announced NAV Available because we were still runway heading; then noticed that Nav Armed was anticipated; but hadn't captured. The Captain used the heading select function. To keep the aircraft on the correct path. At this point we also noticed that the engines were still in Takeoff Thrust Limit. We tried several times to see if NAV would react or anything; but any FMS derived values to the GCP or autopilot did not work. As we continued climb we began to evaluate if we should continue the flight. As a team of three we double-checked all such settings and possibilities. There was no obvious action and the buttons pushed on the FMS and GCP didn't have the desired results. When the PROF key was pressed to display the climb page all values were blank or boxes. At this time we also were not sure of the reliability of our NAV function. With the degradation in our autopilot for maintaining course assigned route as we only had HDG and insecurity to the accuracy of the FMS NAV data presented to us and our route the Captain made the decision to return to the departure airport and we all were in concurrence with his decision. We then went through WAADS verifying weather at ZZZ; starting APU and starting fuel dump. During dump an ACARS message was sent to company advising of turn back. As we were dumping; ZZZ control vectored us south of ZZZ for dumping and eventual vectors Runway XX. After dump auto stopped and we turned dump off from the fuel pump switch there was a LVL 2 Dump VLV 2 Disag. The checklist was completed for this with the system in auto; a note was do not pressurize then cross feed manifolds. However we had a LVL 2 LAT FUEL UNBAL but could not follow the procedure as it requires us to pressurize the crossfeed manifold and the previous checklist was to not pressurize the manifolds. The system in Auto wasn't opening the crossfeed manifold and we chose not to. The approach was setup and briefed for ILS Runway XX and as we advised of ready for approach. On descent we noticed there were no overspeed or low speed warning bars on the airspeed indicator. As we slowed around 200 kts. in descent clean config the stick shaker turned on; power was added and airspeed increased causing the stick shaker to turn off. We then extended slats and we're vigilant about our speed since we realized we didn't have normal cues. When vectoring form the ILS the FMS was still enunciating NAV Armed. The all/land button was not responsive so the decision was to fly the approach manual as we could not determine if the autopilot was going to go on to the appropriate mode. Upon intercept of the localizer; we were right to the glideslope as well and got above the glide path and the approach became unstabilized. We executed a missed approach and advised tower. Tower asked if we were requesting priority handling; we responded negative but asked for a longer vector and ATC advised we'd get a 16 mile final and gave us a downwind vector. As the FMS was setup for a second approach the NAV Armed annunciation went blank. As we were vectored to the final; the APPR/Land enunciated normally. On localizer indication becoming active; the autopilot captured the localizer and a normal approach to landing was made. As our normal policy when a fuel dump is made emergency equipment followed us along the runway and taxiways to parking to insure that there was no hazmat leaks or FOD from the aircraft.




Synopsis: MD11 pilot reported a diversion after #2 Auto Pilot failed and caused additional navigation systems failures and required fuel dumping.