Regional Jet 200 ER/LR (CRJ200)
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Confusion; Human-Machine Interface; Training / Qualification; Workload
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Landed in Emergency Condition; General Declared Emergency; General Maintenance Action
Aircraft
Received C overtemp message. While running QRH that message went out and received APU fire message. Started running IAI and fire message went out and got APU fire fail message. I was now not sure there was no fire and was not confident in the APU fire warning system; so I ran the IAI; pressed APU fire switch and discharged the APU fire bottle.
A CRJ200's APU FIRE/OVERHEAT warning system malfunctioned first indicating an OVERTEMP; followed by a FIRE warning and then an APU FIRE FAIL alert. The APU fire bottle was fired; and an emergency declared.