Regional Jet 700 ER/LR (CRJ700)
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Communication Breakdown
Aircraft Equipment Problem Critical; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Overcame Equipment Problem; Flight Crew Returned To Clearance
Human Factors
While on arrival into BNA on the new PASLY RNAV STAR we were given a descent to cross a fix at 15;000 FT from FL230. Then we were to continue to descend via the STAR eventually to 4;000 FT. After configuring the FMS the descent rate required to meet the restriction was too high for us and we notified ATC we would not be able to comply. ATC reissued a clearance to stop decent at FL180. While in the descent I had already changed the altimeter to transition below FL180. The local altimeter was high so when we noticed the issue we were approximately 300 FT low. ATC almost at the same time issued a clearance to a lower altitude. As the new arrival procedures become more familiar to crews this is less likely to happen.
The altimeter setting was changed by the Captain in anticipation of crossing the transition altitude as per the original clearance as opposed to following procedure and waiting for the appropriate time for the doing so; in this case; as driven by the checklist. In the future; following established procedures and proper checklist usage could prevent similar occurrences.
After being cleared comply with a crossing restriction below the transition altitude on descent; the flight crew of a CRJ-700 determined they would be unable to comply and were recleared to maintain FL180. Because the flying pilot had already set his altimeter to the local pressure setting they initially leveled several hundred feet low.