Date: 201502
Local time of day: 0601-1200
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737-300
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Physiological - Other; Distraction
Second reporter function: First Officer
Anomaly: Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Attendant; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Returned To Departure Airport
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: On initial climb out; passing through about 16;000 feet MSL; we noticed a strong odor in the cockpit; accompanied by a small amount of haze/smoke. About the same time; the A Flight Attendant (FA) called the cockpit to report smell of fumes and smoke in cabin. The flight attendants reported the smell seemed to be getting stronger and smoke was increasing (especially in the aft of the aircraft). Subsequently; the aft lav smoke detector alarm activated.  Decision was made to return to back to departure airport.  We accomplished the SMOKE/FIRE/FUMES ON THE AIRCRAFT Checklist through step 10. Flight Attendants reported smoke appeared to be increasing; so accomplished AIRCRAFT SMOKE/FUMES REMOVAL CHECKLIST. After this was completed; we accomplished the Descent Checklist and were soon below 10;000 feet MSL and in the airport traffic area. Visual Approach and landing to Runway 28 were uneventful.


Second narrative: During the course of our pre-departure preparations; the Captain informed me that the aircraft had air aborted on the previous flight for smoke/fumes. Logbook documentation by Maintenance indicated the problem could not be duplicated and the aircraft was released for flight.Approximately passing 14;000 feet; our flight deck jumpseat rider; a fellow Company Pilot; commented that he sensed a 'haze' developing on the flight deck. Both the Captain and I had been focusing our attention outside; but quickly agreed with the jumpseat that a smoke/fire/fumes situation was developing. The Flight Attendants chimed several times with questions and updates. Some of these interruptions were useful (smoke/fumes intensifying; aft lav smoke detector going off; etc). However; one of the Flight Attendants asked us to drop the Passenger oxygen masks which required a quick explanation as to why that was not a good idea reference the associated Warning in the QRH.I honestly do not recall how far down the checklist we got before landing duties became more pressing. In accordance with the checklist advisory; we did not delay landing in an attempt to complete all steps.


Synopsis: The flight crew of a B737-300 noted fumes and acrid odors during climb out closely followed by reports of similar awareness by the flight attendants. The flight returned safely to the departure airport. The aircraft had returned to the departure airport the previous day for the same reasons yet; there was no evidence of an actual incendiary event.