Regional Jet 900 (CRJ900)
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Situational Awareness
ATC Issue All Types; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Human Factors
After takeoff out of HPN PM contacted departure. Checked in with climbing out of 2000 for 3000. ATC responded with roger; climb maintain 12000. PM responded climb maintain 12000. 12000 was selected in the altitude alerter. ATC was busy. ATC asked who is off HPN. We did not respond because we already talked to ATC and there was another aircraft behind us for takeoff. So we figured it was the other aircraft. ATC again asked who's off HPN. We guessed maybe he was referring to us. We answered [we were]. He stated he wanted us on 120.8. PM switched to 120.8 and checked in. PM questioned the 12000 feet and ATC stated 'no I want you at 3000'. I observed an altitude of 3600. Turned auto pilot off and descended to 3000. PM stated altitude reached 3800 before we started our descent. I also observed the MFD TCAS and noticed there were no aircraft within 10 miles of our position. We leveled off at 3000. The next communication from ATC was climb maintain 7000 turn left to heading 270. Then ATC handed us off to the next NY departure controller. After that ATC never said a word about the altitude question. Threats; NY busy airspace. ATC simulcasting on different frequencies. ACARS not working at gate and had to do manual weight and balance form. 28 minutes from door close to takeoff. Maybe rushing a little bit.Possible error; the paper that had our clearance on it fell on the floor on taxi out. Which would have been double checked on the briefing. The departure frequency was 120.8. Which is not the normal departure frequency for the HPN 5 departure. 120.8 is the second frequency listed on the HPN 5 departure. We used the first frequency listed on the plate. I learned if I don't hear a call sign with an altitude change I will not accept the altitude change.
There was a mix up in departure freqs from what was on the assigned departure chart and what was assigned. This should have been verified prior to departure.
CRJ-900 flight crew reported an altitude deviation stemming from ATC communication confusion.