B767-300 and 300 ER
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Workload; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types
Air Traffic Control Issued New Clearance; Flight Crew FLC Overrode Automation; Flight Crew Overcame Equipment Problem
Aircraft; Procedure
Captain was Pilot Flying and I was acting as right seat support. ATC completely changed our filed route of flight when we requested our clearance. Captain called Dispatch and informed them of the changes. We took off from Runway 30L on the JHART six departure. The takeoff weight was extremely light at approximately 232;000 pounds. LNAV was armed for takeoff and the VNAV and autopilot was engaged at 1000 ft. After lift off the plane climbed extremely quickly and did not track our course very well. The plane steered right of course. But not a lot. Our first level off was at 5;000 ft. but the plane did not appear to be leveling off quick enough and Captain disengaged the autopilot and flew the plane. I saw the VNAV ALT in the FMA window. The plane was manually leveled off at 5;000 ft. It was an extremely busy time in the cockpit. About that time ATC cleared us to 15;000 ft. and direct JHART. After the clearance was received everything in the cockpit went back to normal and the auto pilot was re-engaged.This is the second time this week this is happened to me in a very light weight takeoff. The 767-300 auto pilot does not appear to be strong enough to handle light weight takeoff. I suggest we remove auto pilot must be used on RNAV one departures from our FCOM. And give the Captain the option to hand fly these departures if it is allowed by the FAA.
B767 Captain reported that an autopilot malfunction during departure resulted in a clearance deviation.