Date: 202102
Local time of day: 1801-2400
Location: ZZZ.TRACON, US
Flight conditions: VMC
Weather elements / visibility: 5
Light: Night
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Climb; Initial Climb
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Time Pressure
Second reporter function: First Officer; Pilot Flying
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Aircraft Equipment Problem Dissipated; Flight Crew Landed in Emergency Condition; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification; General Flight Cancelled / Delayed
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Ground ops and takeoff were all nominal. During the climb phase passing approximately 18;000 feet MSL; we noticed a strong smoke odor with visible smoke and haze emanating from the courier area. The burning; smokey; smell was increasing. We requested priority handling with ZZZ center and stated the nature of our priority and our request to begin an immediate descent into ZZZ for Runway XXR. We ran the Smoke/Fumes checklist. The procedure cleared the smoke very quickly. An expeditious approach was conducted to ZZZ XXR. Crash/Fire/Rescue inspected the ac and followed us to parking without any further issues.


Second narrative: Captain was PM; First Officer was PF: Preflight; engine start; taxi and take off were all normal.  Climbing through roughly FL180 I noticed a slight burning smell which seemed to be intensifying in both smell and irritation level to eyes/throat.  Took a look behind me and noticed the light in the ceiling by the cockpit door shining down on a dense hazy smoke.  Mentioned to the Captain to take a look behind him and he noticed it as well.  We requested priority handling with ZZZ Center and requested an immediate return to ZZZ for a visual backed up by the ILS to Runway XXR.  As we began the turn and descent back towards ZZZ; the Captain ran the 'Non-Alert' Smoke/Fumes Removal Checklist.  At some point; approach control was notified of our intentions to be high speed below 10;000 feet.  After descending below 10;000 feet; the cabin was depressurized via the QRH procedure and the smoke/smell dissipated relatively quickly.  Flight Control was notified via Sat Phone of our intentions to return to ZZZ.  Approach and landing went smoothly.  After landing; we vacated the runway and came to a stop on the parallel taxiway so Airport Fire and Rescue services could take a look around at the exterior of the aircraft.  After getting the all-clear; we taxied back to the ramp and met with maintenance and eventually with EMS to get checked out.


Synopsis: Air carrier flight crew reported a flight deck fumes event during departure climb resulting in a return to the departure airport.