Date: 202002
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: IMC
Light: Daylight
Aircraft: Challenger 650
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Flight phase: Takeoff / Launch; Climb
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: APU
Component problem: Improperly Operated
Reporter organization: Air Taxi
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Situational Awareness; Confusion; Distraction
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: In-flight
Result: Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; Flight Crew Overcame Equipment Problem; General Flight Cancelled / Delayed
Contributing factors: Aircraft; Human Factors; Procedure
Primary problem: Procedure

Narrative: During the after takeoff check my finger got jammed between the APU and right generators. This resulted in turning both generators off. Alarmed; I had a reflex action and spontaneously tuned the left generator off. This happened without any thought and I don't know why I did this. These actions resulted in deployment of the ADG (Air Driven Generator). After deployment; I reset all three generators on and transferred emergency bus power back to the left generator.  With power restored; we executed the ILS XXR approach; taxied and parked.


Second narrative: After takeoff; while climbing towards the assigned initial altitude of 5;000 feet on the assigned SID; the Captain (the pilot monitoring); turned off all AC power to the aircraft while performing his after-takeoff flow. Power was restored within seconds; but the ADG (Air Driven Generator) had already dropped. The Captain announced to Approach Control that we were going to need to return to the field. As the pilot flying; I continued to maintain positive aircraft control while the Captain tried to configure the cockpit for a return to the departure airport. After power was restored and I could see the AC synoptic page; I was able to add back in the autopilot automation to help reduce my workload and piece a plan together with the Captain to return for a landing.As the pilot flying; there was not much for me to do but aviate; navigate; and keep a watchful ear to the radio communications that the Captain was having with Approach Control. It was unbelievably stressful; and the level of task saturation was high for both of us. To the best of my abilities; after the situation had calmed down a bit; I tried to mentally load shed and stay focused on flying the jet to a successful landing from the abnormal situation.When a pilot accidentally creates an unanticipated abnormal situation; like the one described above; there is a massive startle effect. So much so; that you almost don't know what to do for a few seconds because it is so surprising. The loss of all AC power on climb out is not a scenario that you practice in the simulator. During initial type rating training; you may see it; but when it happens in the airplane while climbing through IMC conditions; it's completely unexpected. So much so; that I had to ask the Captain what the noise was; at which point; he identified that it was the ADG (Air Driven Generator). I had only heard the sound one time before in the simulator; it was not a sound that I was able to immediately identify in flight. I suggest that this scenario be used in some way for future pilot training so that same thing doesn't happen again to another crew.


Synopsis: CL-650 flight crew reported accidentally deploying the Air Driven Generator.