A300
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; General Maintenance Action
Aircraft
After pushback from gate and after both engines started; First Officer and I noticed a strong odor. To me it smelled like crayons; and even maybe a slight electrical smell. After configuring aircraft and during taxi to runway; the smell disappeared prior to taking off. After takeoff; we had a TCAS fail; Flaps 2 fault; First Officer side ADC failure; and the odor returned. So; after running appropriate check lists; we elected to return to ZZZ as we weren't going to proceed all the way to ZZZ1 with these conditions.
Strong smell after engine start detected that became intermittent.  It smelled like a laminator machine. It was intermittent so we elected to continue with no smell detected at takeoff. On takeoff; we experienced a TCAS failure and some sort of instrument error on the FO panel (speed zipper disappeared with red 'spd lmt' light illuminated). Shortly after it was followed by a flaps 2 fault without any movement of the flaps handle. While troubleshooting the flaps we also noticed the smell grew stronger. With all those things combined we decided to return ZZZ.
A300 Captain reported a burning smell in the cockpit and multiple system failures after takeoff; resulting in a return to the departure airport.