Medium large transport flight crew responds to TCAS ii alert. Altitude deviation.

Attributes
ACN	163720
Time
Date	199011
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sna
State Reference	CA
Altitude	msl bound lower : 4000 msl bound upper : 4800
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : sna
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : on vectors enroute airway : sna
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : atp pilot : commercial
Experience	flight time last 90 days : 200 flight time total : 5800 flight time type : 2340
ASRS Report	164720
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 12000 flight time type : 400
ASRS Report	164150
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course none taken : anomaly accepted
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

While level at 4000', the controller issued traffic and directed a left turn from 220 degree to 180 degree. Simultaneous to the controllers instructions the TCAS ii issued traffic alert and very shortly after commanded 'climb'. The captain disconnected the autoplt which was being used for cruise, and initiated a 1000-1200 FPM climb as directed by TCAS ii. We got to an altitude of 4800' before coming immediately back down to 4000'. Traffic was never seen. Controllers frequency was very busy, and it took about 30 seconds more before I (first officer) could inform him of our altitude excursion. His comment was, 'yeah, that's the traffic I turned you for.' observation. TCAS ii was very loud, and actually cut out some of the controllers initial instructions. If instructions from ATC had been issued during the 'climb-climb-climb' command, they would not have been heard.

Original NASA ASRS Text

Title: MLG FLT CREW RESPONDS TO TCAS II ALERT. ALT DEVIATION.

Narrative: WHILE LEVEL AT 4000', THE CTLR ISSUED TFC AND DIRECTED A L TURN FROM 220 DEG TO 180 DEG. SIMULTANEOUS TO THE CTLRS INSTRUCTIONS THE TCAS II ISSUED TFC ALERT AND VERY SHORTLY AFTER COMMANDED 'CLB'. THE CAPT DISCONNECTED THE AUTOPLT WHICH WAS BEING USED FOR CRUISE, AND INITIATED A 1000-1200 FPM CLB AS DIRECTED BY TCAS II. WE GOT TO AN ALT OF 4800' BEFORE COMING IMMEDIATELY BACK DOWN TO 4000'. TFC WAS NEVER SEEN. CTLRS FREQ WAS VERY BUSY, AND IT TOOK ABOUT 30 SECS MORE BEFORE I (F/O) COULD INFORM HIM OF OUR ALT EXCURSION. HIS COMMENT WAS, 'YEAH, THAT'S THE TFC I TURNED YOU FOR.' OBSERVATION. TCAS II WAS VERY LOUD, AND ACTUALLY CUT OUT SOME OF THE CTLRS INITIAL INSTRUCTIONS. IF INSTRUCTIONS FROM ATC HAD BEEN ISSUED DURING THE 'CLB-CLB-CLB' COMMAND, THEY WOULD NOT HAVE BEEN HEARD.

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.