Date: 201605
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Takeoff / Launch
Aircraft component: Cockpit Window
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Second reporter function: Pilot Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Other takeoff roll
Result: Flight Crew Rejected Takeoff
Contributing factors: Human Factors; Aircraft
Primary problem: Human Factors

Narrative: I was the Pilot Monitoring (PM) for takeoff. Shortly after initiating the takeoff roll; my sliding window rolled back. When this happened; the window caught my headset wire and twisted the headset on my head. I turned to check the wire was free; and was then readjusting it; when suddenly my First Officer (FO) asked me something about my window. I was not sure; (due to noise and headset position) but I believe it was something to the effect of if I was closing the window. I responded no. He immediately announced and conducted a rejected takeoff. I was quite surprised he didn't simply continue the takeoff as the window could easily have been closed once safely airborne. Nonetheless; I felt it was prudent; under the circumstances; to simply take control of the aircraft and complete the rejected takeoff. The reject was uneventful; and we cleared the runway as requested by Tower. After arriving at a designated stopping point; I reviewed the rejected takeoff procedure in the QRH. We also looked at brake cooling requirements in the [flight computer]. On this note; I asked my FO (since I did not see it myself) what speed he initiated the reject at. He said 75 knots. I believed it was actually at a slightly higher airspeed; and therefore checked the [flight computer] for speeds of 85 and 90 knots. 85 knots showed 0 brake cooling time required. 90 knots showed nine minutes required; which by then; we had. I then checked minimum takeoff fuel; which was not a problem. I informed Dispatch of what had occurred; and of our intention to continue. The reply via ACARS was 'Ok.' We re-accomplished both the Before Push and Before Takeoff Checklists and departed without further incident.Preventative Measures: Two big lessons learned here are as follows: First; I should have announced loudly and clearly 'Continue.' Yes it was a bit noisy; and my headset was twisted on my head as a result of the window knocking the wire; however; I could easily have communicated in a loud enough voice to be heard. In all honesty; while I am aware that for any anomaly (particularly above 80 knots) this communication is required; due to the distraction with my headset; and the fact it didn't even cross my mind he would decide to reject; I did not say 'Continue.' Second; I must; in the future; be more 'assertive' when checking my window during pre-flight. As a matter of explanation; I do (and believe I did in this case check the window). However; as I have observed by many; my technique has never been to bang on the handle with the side of my fist. Generally; I have always; (unless it appeared the window was not correctly closed for whatever reason) simply tapped on the handle while visually determining it is closed. In this case; there seemed no visual indication the window was not properly closed; yet it obviously was not completely locked in place. I will be much more cognizant of this possibility in the future and intend to check it by physically grasping the handle and checking to see it is secure in the locked position.


Second narrative: Takeoff [in a] fully loaded -800; flaps 15; First Officer (FO) Pilot Flying (PF). Thrust set at 102.2% N1. As the aircraft started to move; the Captain's side window opened abruptly. The Captain's response was to shut the window; as FO continued takeoff roll. Captain remained distracted by open window and now has his back toward the FO. Captain stated; 'I can't close the window!' No [risk management] input; no callouts; no situational awareness on the part of the Captain. Just complete distracted obsession with closing the side window. As PF; I am now also very distracted at all of this; the engine noise at 102% made hearing the Captain difficult; but still nothing heard except not being able to close the window. I was expecting to hear 'reject;' since we were still in the low airspeed regime; but that call; or the continue call; never happened. I opted to abort on my own. Mind you; it's [a short runway]; and we are accelerating at full power. A decision needed to be made in seconds. I said; 'I'm aborting the takeoff;' thrust levers to idle; reverse thrust. My honest 'guess' was airspeed below 80; but in all honesty I couldn't tell; as this all occurred very quickly; and the distraction was more than I expected. I notified ATC of the aborted takeoff. The Captain now faced forward; and realized I performed an aborted takeoff and asked me 'why?' He took the controls. ATC asked us to accelerate to exit at the high speed taxiway. We complied. ATC asked why we aborted. I told them about the window. On the taxiway; the Captain again attempted to close his window; while I notified the Flight Attendants (FA); and made a PA announcement to the passengers. Finally; the Captain got his window shut. We taxied to the pushback location abeam the gates. The Captain checked the QRH; while I worked the OPC for brake cooling. I asked the Captain about fuel; and we had enough to continue. We ran the checklist from 'Before Taxi' to 'Departure Checklist' again. No brake cooling was required; so we departed. Take off and flight uneventful.Preventative Measures: Perhaps a place on the checklist to check Windows; 'Doors and Windows.' Response 'closed' or 'secure.' Just a reminder to check them. I really expected the Captain to abort immediately; after the window opened. We were below 45 knots; as the airspeed tape didn't even move yet. What's the problem with stopping and fixing this issue on the taxiway; and then departing? Are we really that pressured to be on time; or avoid paperwork?


Synopsis: B737-800 flight crew reported rejecting the takeoff when the Captain's side window opened.