Regional Jet 200 ER/LR (CRJ200)
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe
General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Weather
Upon arriving at the plane for the first flight of the day I completed the safety checks then proceeded to start the APU. After getting little rotation I selected stop. After a few minutes the First Officer again attempted the start with the same indications. Knowing that we could not board the passengers due to the temperature; around 24 that morning; we advised operations of the situation and requested a GPU; heat cart and a start cart. After these were in place we went back on the aircraft and the First Officer attempted an APU start again with very little rotation and a redline EGT prompting a shutoff. I then went outside and a ramper informed us that he saw sparks coming from the APU exhaust and at that time I noticed some smoke coming out of the closed APU inlet door. The First Officer and I walked to the rear of the aircraft and did not see a fire but chose to have the fire truck come over to be on the safe side and to double check. After the truck arrived and after some looking around they confirmed that there was no fire. I called maintenance and talked it over and a write up was made and a mechanic was sent out.After knowing that there was no fire perhaps I could have investigated a little further before getting the airport fire involved.
The third attempt to start the APU of a CRJ-200 on a cold morning; resulted in insufficient spool up and an EGT at or above redline followed by a report from ground crew advising of sparks from the APU exhaust. CFR was called as a precaution and maintenance was initiated.