Date: 202107
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Night
Aircraft: B767-300 and 300 ER
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Takeoff / Launch
Airspace: Class D ZZZ
Aircraft component: Cockpit Window
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Troubleshooting; Distraction; Workload; Time Pressure; Communication Breakdown
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; 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 Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: As Captain; I was the Pilot Monitoring and the First Officer was the Pilot Flying for this flight. On the take off roll at approximately 90 to 100kts; I hear the First Officer make the comment 'There seems to be a lot of airflow through this window'. I glanced over and to see from my point of view that the window appears to be closed. I shift my eyes back to the runway centerline; airspeed and engine instruments while thinking about what he said. At approximately 110kts; it becomes loud with high airflow into the flight deck. The First Officer shouts 'My window is open'. I quickly glance over to his side to see he has his left hand on the control wheel and is holding the R 2 flight deck window closed by the window lock lever with his right hand. I immediately took the controls. At this time we are approximately 120kts just prior to V1 (129). I took a quick glance at my First Officer and back to my instruments; I saw that we were Vr + 8 to 9kts. I then rotated. I saw a positive rate of climb and shout 'gear up'. The First Officer assumed pilot monitoring and raised the landing gear. I shouted 'Can you crank the window closed at all?' He responded 'No; it won't close'. At this point; Tower had advised us to contact Departure. I selected the Center Autopilot; VNAV & Heading Select with a heading of 360 as assigned. I opened the speed window and remained at Flaps 5 to prevent the airplane from accelerating. I figured the faster we would go; the louder the flight deck would be and the more the First Officer would struggle to hold the window in position. The First Officer shouts 'I can't hear anything from ATC.' Around 3;400 ft. I contacted Departure and informed them that we need to stop climb and return to the airport because we have a flight deck window opened. We were given a left heading of 270 and to maintain 4;000. We performed the after takeoff checklist. My First Officer states 'I can't hear anything from ATC but what do you need from me?' I responded 'ATC is giving us vectors back to ILS RWY XX. If you can; get flight deck performance for Runway XX and set us up for the ILS RWY XX; I'll do a quick brief; then we will do our Descent and Approach checklist.' With one hand still on the window crank; the First Officer did just that and along with his flow. ATC gave us another vector and asked if we need more time. I told ATC that we were not ready and asked to continue heading at 270 and 4;000. Once we were set up; briefings and checklist were complete; I advised ATC we were ready for the approach. Since I was flying while doing the radios myself and the First Officer with only one free hand available; I decided it would not be prudent to be heads down and message Dispatch through ACARS. I felt the priority was to fly the plane and get us safely on the ground. I informed ATC 'We [request priority]; 2 souls on board and approximately 4 and half hours fuel on board'. ATC asked the nature of the [situation] and I replied 'We have a flight window cracked'. I meant to say cracked open; however; the noise from the airflow was a little distracting. ATC gives us an intercept heading of 100 and clears us for the approach. We were stable; fully configured; and all checklists were complete prior to the final approach fix. At 800 feet AGL we broke out of the clouds. I had the airport in sight and disengaged the autopilot. A normal landing was made at approximately 265;000 lb. We informed Tower that we did not need assistance and taxied to parking. Upon taxi in; I do not know if the First Officer closed the window or left it in its previous condition from flight; opened. Perhaps he left it alone so that Maintenance could inspect. I wrote up that the First Officer R2 flight deck window opened on takeoff/climb and I waited for them to inspect. There was no damage or defects noted.I honestly do not know if it was a Flight Deck Window malfunction or if it was ever truly locked. Both of us had opened our Flight Deck Windows on the ground during preflight because the APU was off and the temperature was in the 70's. About 30 minutes prior to block out; I started the APU and we closed our windows. In the Before Start portion of the checklist; I verified my flight window was closed and locked with strut at a 90 degree position. I heard the First Officer respond 'Closed and locked'. I could see his Window Lock Lever was in the forward and locked position; however; I could not verify if his decal showed 'CLOSED' nor if the strut was at a 90 angle simply because of the angle from where I was sitting in the Captain's seatI think that in the moment; the First Officer did a great job of prioritizing aircraft control in such a critical phase of flight. To be in the high speed regime of takeoff; so close to V1 and to keep 'aviating' while a huge startling distraction occurred was commendable. He also; kept his head in the game and jumped to the pilot monitoring duties without delay. He prompted me for the after takeoff checklist as we were about to level off at 4;000. If I could have done one thing over; I would have shouted 'My controls' in a louder voice. I didn't take into consideration that the First Officer could not hear well at that point.I'm also appreciative of our Company training video made by Boeing of a flight with the flight deck window opened. I'm glad that I was shown to me during my 767 upgrade training. I never thought I would be in that situation but thankfully I had some idea of what to expect. The plane will be extremely loud and distracting but it will safely fly.


Second narrative: During takeoff my window opened immediately after the CA (Captain) called '80 knots; thrust set.' I was PF and saw the window rolling aft. I grabbed the window handle with my right hand while continuing to fly. I maintained runway centerline and described what happened by shouting cross cockpit to allow the CA to have the information and make an appropriate reject decision. About 10 knots before V1 the CA took the aircraft. I couldn't hear him verbally call V1 due to the cockpit noise and open window. Perhaps I didn't hear him call V1 because he had already taken the aircraft. Regardless it was loud and my audio panel wasn't set up to compensate for the noise.When the aircraft rotated I immediately assumed the role of Pilot Monitoring. He shouted to raise the landing gear and I did. The CA flew and took the radios because I had shouted cross cockpit that I couldn't hear ATC well enough to communicate. Both of us had to compensate because of the noise. The CA selected heading select and turned left to our assigned heading of 360 and elected to select VNAV and Center Autopilot Command almost simultaneously.The CA requested to stop climb around 5;100 MSL and informed me that we would return to ZZZ. Around this time I had determined that as long as I held the window with a good amount of strength it wouldn't roll open. I adjusted my interphone and ATC freq to Max volume so that I could hear. I then asked the CA if he was ready to run the After Takeoff Checklist and we did. Everything from that point forward was standard and in order except that the CA had to turn the Standby Attitude Indicator to ILS mode because I had one hand holding the window; the CA [advised ATC]; and did the radios. After we landed all roles were normal and the taxi in was standard.This situation is dynamic. I think perhaps a better verbal transfer of aircraft control on takeoff roll but we effectively handled the situation. I thought the CA was going to reject the takeoff. By the time he processed what was going on he decided it was safer to continue the takeoff. It was loud and we coordinated the best we could in this situation.


Synopsis: Flight Crew reported the First Officer's sliding window opened on takeoff roll; causing an air turn back and a precautionary landing.