As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT DEPARTED FROM OAKLAND, AFTER TAKEOFF THE NOSE LANDING GEAR WOULD NOT RETRACT. LANDED THE AIRCRAFT BACK IN OAKLAND. UPON FURTHER INVESTIGATION FOUND THAT THE NLG CENTERING PROX SWITCH WAS NOT WITHIN PROXIMITY. FOUND THAT THE CAUSE OF THIS WAS FROM THE STRAP USED WHEN TOWING THE AIRCRAFT WITH A ELECTRO TUG WAS WRAPPED AROUND THE PROX SWITCH AND PULLED IT OUT OF PROXIMITY ENOUGH TO CAUSE THE NLG NOT TO RETRACK.