As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER T/O, LANDING GEAR WOULD NOT RETRACT. EICAS LG AIR/GND FAIL DISPLAYED. MESSAGE APPEARED FOLLOWING ROTATION. FOUND NLG WOW PROX SWITCH BAD. R&R'D PROX SWITCH IAW AMM 32-63-02. T/S IAW FIM 32-63-00-810-801-A. SWUNG GEAR SEVERAL TIMES. OPS CHECK GOOD. OKAY FOR SERVICE AT THIS TIME.