Date: 201406
Local time of day: 1801-2400
Location: ZZZ.TRACON, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737-300
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class E ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: Window Ice/Rain System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Time Pressure; Troubleshooting; Workload
Second reporter function: Pilot Flying; First Officer
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew
When detected: In-flight
Result: Aircraft Equipment Problem Dissipated; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Returned To Departure Airport; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Passing approximately 8;000 FT MSL; I (the Captain) noticed what appeared to be the image of a small flame in the left side window; behind my iPad.  Smoke began to appear. Initially I thought the source of the flame/smoke was the iPad.  I moved my head forward to look behind the iPad.  I noticed glowing ember and sparks coming from the forward bottom of the left sliding window (Number 2 window).  I removed my iPad to better see the source.  I called out smoke to the Cockpit Crew (myself; the First Officer; and a Check Airman jumpseater) and we donned our oxygen masks. Smoke goggles were not donned.  The smoke was not thick enough to warrant the usage.  Also; the ember had started to die out by the time we had completed putting the oxygen masks on. I grabbed the Dispatch Release and put out the ember.  The smoke stopped.  We ran the Smoke/Fire/Fumes Immediate Action Items and Checklist. Left side window heat switch moved to off.  Heat source burned out and smoke dissipated. Decided to return to the departure airport. Flight attendants and passengers briefed of the situation and reassured that the source of smoke was identified and stopped; that as a precaution we were returning; and that we plan to taxi back to the gate normally. When asked; one of the forward flight attendants noted that she smelled smoke; the other did not. ATC advised of the situation and that the smoke had stopped. An emergency was not declared.  Fire trucks were not requested. We requested vectors back to Visual/ILS 6. Jumpseater completed landing calculation duties. Landed below max landing gross weight. The rest of the flight was uneventful and we taxied back to the gate. We had some difficulty establishing crew communications using the masks.  It took about 15 to 25 seconds longer than I would have expected for us to set the switches correctly and at an appropriate volume using the overhead speaker.  For me; I had inadvertently moved my boom/mask switch back to boom while reaching for the R/T-I/C switch.


Second narrative: I turned on the autopilot; leveled at 10;000 feet and the Captain began the Smoke; Fire; Fumes Checklist. I took over ATC communications. I asked ATC for a return to the departure airport. The Captain knew the source of the smoke and per the checklist had turned the affected window heat off. After a few minutes with the mask on the smoke had dissipated enough to take the masks off. We had already begun our descent from 10;000 feet. The Captain during the course of the Abnormal Checklist asked both me and the jumpseater (a Check Airman) if we agreed we should turn around. We all agreed that a return was in order. We landed uneventfully 18 minutes after takeoff.  We deplaned normally upon returning to the gate and conferred with Maintenance. Also; we never did don our smoke goggles. Visibility was never restricted or impeded in any way; so per the immediate action items; they were not needed.I don't think anything could have been done to prevent this malfunction. As far as crew actions; I think we handled the whole situation according to SOP and the Abnormal Checklist. Perhaps we could have left the masks on until taxi in just to make sure there were no dangerous fumes that could have impaired us.


Synopsis: A B737-300 Captain's sliding window heat electrical attach point produced a bluish smoke and glowed amber; so the window heat was turned off. The Smoke; Fire and Fumes Checklist was completed and the flight returned to the departure airport.