Date: 201707
Local time of day: 0001-0600
Location: ZZZZ.Airport, FO
Flight conditions: Mixed
Light: Night
Aircraft: MD-11
Operator: Air Carrier
Operating under: Part 121
Mission: Cargo / Freight / Delivery
Aircraft component: Cockpit Window
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Communication Breakdown
Second reporter function: Captain; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Aircraft Equipment Problem Dissipated; Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: Passing through approximately eight thousand feet; a vibrating low-volume howl began to emanate from the First Officers window. Within what seemed to be approximately a 3-4 second time lapse; this sound became completely unbearable. Communications with ATC as well as communications within the cockpit were extremely difficult; rendering the requirement for maximum volume selections and overhead cockpit speakers on and at maximum volume; to optimize our ability to discern ATC communications. Visual and physical inspections of the First Officer window revealed that the window was properly secured. The window also had an accompanied vibration. The Captain conducted excellent CRM utilization and leadership with all crew members. We determined that a continued flight would not only be detrimental to safety; but would also; and in short order; render permanent hearing damage to us all. All crew members determined that an immediate level off during our climb was needed; followed by communications with ATC regarding our need to return to [departure airport]; as well as the need for us to fuel dump to achieve a safe landing weight for the aircraft. During our eventual descent; we noticed that the extremely loud noise quickly dissipated close to the same altitude it began. All checklists were accomplished. Updated weather information and landing performance was gathered followed by appropriate briefings; to return to our departure airport. A successful landing was ensued with appropriate debriefs with local maintenance personnel whom later shared with us the degradation of the First Officer window seal.


Second narrative: After takeoff climbing through 8;000 feet the FOs window developed a very loud high pitch squeal and vibration in the window. I ask ATC to hold our altitude that we were working a problem. The higher the cabin altitude climbed the louder the noise; to the point where we were having difficulty communicating. After we accessed our situation I decided to return. Asked radar for a fuel dumping area and we were cleared to dump. We also contacted OPS and got a release for a return; which we received. We ran all of our checklists; terminated the dump and briefed the approach. Once we had everything squared away; we flew the ILS for an uneventful landing. MX found a broken window seal. Reasons to dump fuel and return:1) Noise level becoming unbearable and inhibited communication between crew members and hearing ATC; 2) Concern for a window failure due to vibration; 3) A 9 hrs over water flight. I feel I must recognize the crew for remarkable performance and our use of CRM; made for a safe uneventful return.


Synopsis: MD11 flight crew experienced a loud squeal passing through 8;000 that continued to grow louder; making communication difficult. Crew elected to return to the departure airport after dumping fuel.