Date: 201907
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
Airspace: Class B ZZZ
ATC / advisory: Ramp ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Training / Qualification; Confusion; Communication Breakdown
Anomaly: Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: Other During Pushback
Result: General None Reported / Taken
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: On (date) at approximately (time) at Gate X in ZZZ; the ZZZ Ramp Pushback Crew abruptly and unexpectedly initiated pushback of the aircraft into the alley without communicating with the Captain. The Captain attempted and was unsuccessful at getting the attention of the pushback crew to stop the push.  Due to frequency congestion; I was unable to communicate with Ground Control to warn them of our unauthorized pushback onto the ramp. There was an aircraft inbound on Taxiway Y with its taxi light on that was forced to yield to us.  Eventually; I was able to communicate with Ground Control and explain the unauthorized pushback.  Even though there was never any unsafe separation with other aircraft; this was an utterly surprising and unsafe situation that had huge potential to not end well.  The Captain informed ZZZ Operations via Company Radio after the pushback and was told that the ramp was under 'No Headset' Operations because of lightning in the area.  This was the first and only time we were advised of 'no headset' procedures being conducted. Obviously; AOM (Aircraft Operations Manual) 7.1.1 'Pushback Procedures with Hand Signals Only' requires a face-to-face briefing and specifically states: 'When these conditions are encountered; a pushback crew member notifies the Captain of the communications issue and the planned use of hand signals.' This situation angers me because I didn't perceive it as a simple mistake or oversight by the pushback crew; but rather a willful and gross disregard of established safety procedures. There was never a face-to-face briefing conducted or even a simple notification to the flight crew of no headset procedures. When the jet bridge was pulled back from the aircraft; the Ground Crew simply started pushing the aircraft.  Absolutely amazing and unsafe.  ZZZ Ramp must ensure the Flight Crew is aware when conditions requiring 'No Headset' use are in effect so required coordination can be accomplished prior to the pushback.  They should be instructed to never push an aircraft without communicating with the Captain.  These actions are exceptionally dangerous and absolutely have the potential to result in property damage and human injury.




Synopsis: First Officer of a B737 encountered unauthorized pushback from gate from ground crew.