Date: 201308
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Daylight
Aircraft: Regional Jet 700 ER/LR (CRJ700)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
ATC / advisory: Center ZZZ
Aircraft component: Pneumatic Ducting
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Pilot Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Distraction
Second reporter function: Captain; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical; Deviation - Speed All Types; Deviation / Discrepancy - Procedural FAR
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Became Reoriented; Flight Crew Returned To Departure Airport
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: While in the emergency descent for depressurization; the Captain was in the QRH; SOP etc and I was flying; on radios. We had a slow leak; so I took an easy descent down to 10;000 FT; but I had kept my forward speed at 280 KTS. Amid all the distraction of trying to be at least aware of what the Captain was doing on his checklists and navigating from our original course and turning back to the departure airport; and programming the box and trying to answer too many distracting questions from ATC. We had one more caution message pop up for Cabin Alt. Since we were already at 10;000 FT; and this was now an unpressurized flight due to our original emergency for L BLEED DUCT. This Cabin Alt message was completely normal and expected; but the Captain suggested we could go to 9;000 FT and get rid of the message. Nobody wants to see the list of messages get longer; so this seemed like a good idea and I requested and started my descent while still holding 290 KTS. All I can add is that ATC may have even been hinting at our overspeed; but by frequently asking us to verify we are in 'emergency status.' I don't know why it took me so long to get the hint; but we must've gone more than 10-15 miles at that speed... more than enough for an obvious speeding ticket. If they weren't hinting to me; then in general it was a bit distracting. I think the emergency situation puts you outside the box to begin with; but I shouldn't have had any amount of hurry in my descent. I didn't hurry the descent rate; I made the suggestions to the Captain for a very long shallow descent rate for the sake of two infants. So I wasn't in a 'hurry' to get down. It seems like in the middle of the hectic part...we made a knee jerk reaction to a message that was normal and we just wanted to get rid of it. In hind sight; I think we both agree we should've stayed at 10;000 FT until completely briefed; both ready for the entire arrival.


Second narrative: Airspeed in excess of 250 KTS occurred for a short period below 10;000 FT MSL. Preoccupation with QRH procedures and a heavy workload due to an equipment malfunction and a return to field diversion. Devote more attention on priority basics 'aviate; navigate; communicate.'


Synopsis: CRJ-700 flight crew reports unintentionally exceeding 250 KTS below 10;000 FT after an emergency descent.