Date: 201604
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: IMC
Light: Daylight
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Cockpit Window
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting; Distraction
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Returned To Departure Airport
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Cruise climb to FL280. Passing FL180 FO and I started to notice a squealing/high pitched noise coming from my window. Sound volume increased rapidly in the next few thousand feet. At FL210 noise became loud enough to where I had to turn up volume on COM 1 to max to hear and understand ATC. I asked to level off at intermediate altitude to troubleshoot the problem; at that point we were fairly certain it was a pressurization issue so we didn't want to climb any higher and exacerbate [the] problem. We wondered if perhaps the noise was coming from the ramp hail/GPU panel which sometimes lessens if speed is reduced. We reduced speed from 290 to 230 with hardly any change in noise level. Asked FO to consult QRH for any applicable information but none was discovered that was directly applicable to our situation; as airplane was holding pressure sufficiently at that point in time. Contacted MX and dispatch via ACARs. Called FA to see if she heard any noise over the interphone or elsewhere but she didn't. The noise was loud enough to where ATC could hear a high pitch whine in our transmissions and was a significant distraction for us as a crew. MX advised a return to the departure airport. We advised ATC and they gave us a new clearance. We advised ATC that we would have to burn off excess fuel in order to avoid landing overweight. Called FA and briefed her that we would have to return for landing and to prepare cabin. Made a PA and advised passengers that we had a pressurization malfunction and that while we had isolated and contained the problem it was no longer safe to continue the flight to our destination and that we would be returning and be on the ground in approximately 30 minutes.We received a lower altitude; extended the landing gear; and lowered flaps. While burning off excess fuel dispatch contacted us and advised us an overweight landing was approved provided we didn't exceed 360 feet per minute upon touchdown. Texted back to confirm and was reassured that this was approved. Contacted ATC and advised them we could return for landing. Received vectors onto the ILS approach. Touched down very smoothly at zero FPM on VSI; no complications. Advised tower that we didn't require any assistance. Taxied to gate without issue.




Synopsis: EMB145 Captain reported a possible cockpit window seal issue manifesting as a loud; high pitched noise in the cockpit during climbout. There were no pressurization issues and the aircrew returned to the departure airport.