As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB STARTING AT 4000 FT CREW REPORTED LOUD SQUEAL INSIDE COCKPIT. THE FLIGHT DECLARED AN EMERGENCY AND RETURNED TO DEPARTURE WITHOUT FURTHER INCIDENT. MAINTENANCE SECURED AND REPOSITIONED DRAIN TUBE ASSY ON NR 2 OPENABLE WINDOW IAW AMM 56-11-11.