Regional Jet 200 ER/LR (CRJ200)
Flight Crew Air Transport Pilot (ATP)
Time Pressure; Workload; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented; General Physical Injury / Incapacitation
Human Factors
Main aircraft door was closed while external air still connected.  Service door indicated an unsafe condition.  The Flight Attendant attempted to re-secure the service door and fell from the aircraft.The flight had been downgraded to the 200 and the crew had an unplanned aircraft swap. The aircraft came from the hangar and the ramp crew was completing the security sweep when we arrived at the aircraft.  I had already advised the gate that we would need time to complete the preflight checks as well as some additional training; and that I would let them know when we were ready to board.  In addition to conducting IOE with a Captain upgrade who had never flown the 200; I was also advised that I needed to train one of the Flight Attendants on the service door operation.  When I did the exterior preflight I noted that there were bags being loaded in the adjacent aircraft.  Due to the APU exhaust hazard on the 200 and the relatively narrow area between the tail of our plane and the baggage loaders on the adjacent plane; I knew that I could not start the APU yet without an undue hazard to ramp personnel.  This concern later resulted in my failure to start the APU when I should have.  The required training was complete and preflight preparations had progressed sufficiently to commence boarding.  Acting as the First Officer on this flight; I did a manual weight and balance calculation.  When the ramp was ready to disconnect ground air; I should have taken that as the indication that it was safe to start the APU.  However; at the time I was distracted with weight and balance calculations which indicated a Center of Gravity exceeding the forward limit and the need for ballast.  I still had in mind that I could not start the APU so instead I asked the ramp to keep the air connected until we were ready to start the engines.  Once the ballast was added and the paperwork was handed out the door; I mistakenly gave approval for the Flight Attendant to close the main cabin door.  Upon closing the main cabin door the EICAS DOORS page indicated that the service door was unsafe so the flight attendant promptly proceeded to re-secure it.  When the door was opened the flight attendant fell from the aircraft.  It is apparent that by the time the service door was opened enough pressure had built up from the ground air supply that the Flight Attendant was either forced out of the open door or was dragged out while clinging to the door.  Fortunately; the Flight Attendant managed to land on her feet on the ramp.  Apart from being shaken up; she indicated that she was fine.  She had no obvious scrapes or bruises but did say that her forearm was a little sore.  I notified operations that we would need to deplane the aircraft.  After the passengers were off of the airplane; paramedics arrived and escorted the Flight Attendant into the terminal for further assessment.  Maintenance was also notified of damage to the aircraft that occurred when the door opened.The mistake was clearly mine; first in not starting the APU at the appropriate time; and second in approving that the Flight Attendant close the main cabin door while the external air was still connected to the aircraft.  I know better.  We are trained not to do this; but in my haste I followed the force of habit which is typically to close the door as soon as the paperwork is out.  Contributing to this event was the combined pressures and conflicting distractions I felt from a hot aircraft; training requirements; a perceived restriction on starting the APU; weight and balance calculations and time constraints.  I am well aware of the danger inherent in getting rushed and how ones field of vision can become increasingly narrow during periods of stress.  It is something I emphasize regularly to the students that I work with.  While I consider that I am typically deliberate in being methodical and trying to consider one thing at a time; in this case I allowed myself to get that 'tunnel vision' which I believe clouded my mind to the point of inaccurate perception (that I couldn't start the APU) and poor decisions (allowing the door to be closed before first removing the air supply).
A CRJ-200 Check Pilot reported that a Flight Attendant fell from the aircraft while parked at the gate because of deviations from SOP.