As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - FLT NR 750 - AFTER TAKEOFF ORD WHEN LANDING GEAR RETRACTED. RED NOSE LANDING GEAR UNSAFE LIGHT REMAINED ILLUMINATED. EXTENDED LANDING GEAR AND AIRCRAFT RETURNED TO ORD, LANDING WITHOUT INCIDENT. REPLACED NOSE LANDING GEAR STRUT SCHRADER VALVE O-RING. SERVICED NOSE LANDING GEAR STRUT WITH OIL AND NITROGEN. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)