Narrative:

During departure under radar control, leveled off at 4000 ft MSL, assigned altitude. Numerous VFR light aircraft 12 O'clock low. Closing fast on one, the TCASII triggered a TA followed quickly by an RA 'monitor vertical speed' warning. First officer panicked and instead of holding altitude as advised, performed an inappropriate evasive action and descended toward the target. Captain quickly recovered aircraft with minimal altitude loss. Lost 300 ft, bottomed out at 3700 ft MSL. Observed target aircraft visually pass 200 ft below and approximately 1000 ft right of aircraft. Recovered to 4000 ft and continued departure. Recommend more training of airline pilots regarding TCASII maneuvering and evasive action so as to be more understanding of proper avoidance actions.

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Original NASA ASRS Text

Title: FLC OF A WDB ACR ACFT DSNDED BELOW ASSIGNED DEP ALT IN RESPONSE TO A TCASII RA.

Narrative: DURING DEP UNDER RADAR CTL, LEVELED OFF AT 4000 FT MSL, ASSIGNED ALT. NUMEROUS VFR LIGHT ACFT 12 O'CLOCK LOW. CLOSING FAST ON ONE, THE TCASII TRIGGERED A TA FOLLOWED QUICKLY BY AN RA 'MONITOR VERT SPD' WARNING. FO PANICKED AND INSTEAD OF HOLDING ALT AS ADVISED, PERFORMED AN INAPPROPRIATE EVASIVE ACTION AND DSNDED TOWARD THE TARGET. CAPT QUICKLY RECOVERED ACFT WITH MINIMAL ALT LOSS. LOST 300 FT, BOTTOMED OUT AT 3700 FT MSL. OBSERVED TARGET ACFT VISUALLY PASS 200 FT BELOW AND APPROX 1000 FT R OF ACFT. RECOVERED TO 4000 FT AND CONTINUED DEP. RECOMMEND MORE TRAINING OF AIRLINE PLTS REGARDING TCASII MANEUVERING AND EVASIVE ACTION SO AS TO BE MORE UNDERSTANDING OF PROPER AVOIDANCE ACTIONS.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.