TCASII RA creates an altitude deviation altitude undershot in climb.

Attributes
ACN	193139
Time
Date	199110
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : pdx
State Reference	OR
Altitude	msl bound lower : 6600 msl bound upper : 8000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : pdx
Operator	common carrier : air carrier
Make Model Name	Large Transport
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Route In Use	departure other departure sid : sid
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft
Flight Phase	cruise other descent other
Route In Use	approach : visual
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 18000 flight time type : 80
ASRS Report	193139
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : undershoot non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 3000 vertical : 0
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Copilot flying. Cleared to 13000 ft. TCASII gave TA. TCASII screen indicated traffic at 11 O'clock about 2-3 mi, altitude +700 ft. No visual contact at that time. TCASII changed to RA and commanded a descent. Target was still 11 O'clock 1-2 mi. Altitude +400 ft. We had started a descent by this time and I acquired the traffic visually at about a half mi. The traffic, small aircraft Y, was also in a descent and a steep turn. We passed clear and resumed our climb. Our lowest point of descent was 6600 ft. ATC called the traffic at 11 O'clock and 1 mi. There was no other conflict I'm aware of.

Original NASA ASRS Text

Title: TCASII RA CREATES AN ALTDEV ALT UNDERSHOT IN CLB.

Narrative: COPLT FLYING. CLRED TO 13000 FT. TCASII GAVE TA. TCASII SCREEN INDICATED TFC AT 11 O'CLOCK ABOUT 2-3 MI, ALT +700 FT. NO VISUAL CONTACT AT THAT TIME. TCASII CHANGED TO RA AND COMMANDED A DSCNT. TARGET WAS STILL 11 O'CLOCK 1-2 MI. ALT +400 FT. WE HAD STARTED A DSCNT BY THIS TIME AND I ACQUIRED THE TFC VISUALLY AT ABOUT A HALF MI. THE TFC, SMA Y, WAS ALSO IN A DSCNT AND A STEEP TURN. WE PASSED CLR AND RESUMED OUR CLB. OUR LOWEST POINT OF DSCNT WAS 6600 FT. ATC CALLED THE TFC AT 11 O'CLOCK AND 1 MI. THERE WAS NO OTHER CONFLICT I'M AWARE OF.

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.