B767-300 and 300 ER
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor
Flight Crew Last 90 Days 92; Flight Crew Total 5800; Flight Crew Type 2032
Training / Qualification; Troubleshooting
Aircraft Equipment Problem Critical; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance
Flight Crew Returned To Departure Airport; General Maintenance Action
Aircraft
While climbing out on a ferry flight after the aircraft had been in heavy maintenance; the Controller gave us clearance to climb to 7;000 FT. My (First Officer side) altimeter failed around 4;000 FT and I was watching it to see if it would come back on; before switching to Alternate Air Data. Around 5;000 FT; both Captain and First Officer vertical guidance on the Flight Director disappeared; then came back. The same thing happened on the Functional Check Flight that I had performed with another Captain the day before. Approaching 7;000 FT; we noticed the 'Alt Cap' annunciation; but the aircraft was rapidly approaching the altitude. The Captain even mentioned that he wondered if the plane would level off there. The plane did not level off; and by the time the Captain turned off the autopilot and leveled the aircraft; while maintaining 220 KTS (as required by the departure); we were at 7;300 FT. Departure told us again to level off at 7;000 FT and the Captain descended back down to 7;000 FT. I switched to Alternate Air Data on my side to regain an altimeter. We tried all three autopilots and none of them would follow the correct commands. We also noticed at this time that the 100's window on the altitude window of the mode control panel would not change from 0. We turned off all automation and began to set up to return back. We landed without further incident. Maintenance determined that the primary cause was loss of an Air Data Computer; along with a faulty altitude window on the Mode Control Panel. In the future; I'll be more careful when I don't think that the aircraft will level off; even though all indications except the climb rate; showed that it would. We should have turned off the autopilot earlier to level off at the correct altitude.
A B767-300 Air Data Computer and Mode Control Panel both malfunctioned after a heavy maintenance check and the aircraft did not level at an intermediate altitude on the SID.