TCASII RA creates an altitude deviation altitude excursion by PIC.

Attributes
ACN	187877
Time
Date	199108
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : stl
State Reference	MO
Altitude	msl bound lower : 10000 msl bound upper : 10400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : stl
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other cruise other
Route In Use	arrival other arrival star : star
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	departure other departure sid : sid enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : cfi pilot : atp
Experience	flight time last 90 days : 180 flight time total : 4550 flight time type : 180
ASRS Report	187877
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 15000 vertical : 200
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other

Narrative:

St louis approach cleared us to 7000 ft from 10000 on modoc arrival. We received this message from TCASII 'traffic, traffic'. It showed traffic moving from 1 O'clock to 11 O'clock below us. 'Climb crossing climb'. We could not get visual contact with the intruder, so we began a climb. The TCASII called 'clear of conflict' at about 10400 ft. We advised ATC as we climbed on TCASII RA. He instructed us after 'clear of conflict' to maintain 10000 ft. As we descended to 10000 we received another TCASII alert 'traffic, traffic...descend crossing descend'. We got visual contact with the intruder at 10200. It was at 10000 crossing right to left at approximately 3 mi. We maintained visual. We asked ATC about the traffic. He confirmed 'at 10000, 11 O'clock'. We descended to 10000.

Original NASA ASRS Text

Title: TCASII RA CREATES AN ALT DEV ALT EXCURSION BY PIC.

Narrative: ST LOUIS APCH CLRED US TO 7000 FT FROM 10000 ON MODOC ARR. WE RECEIVED THIS MESSAGE FROM TCASII 'TFC, TFC'. IT SHOWED TFC MOVING FROM 1 O'CLOCK TO 11 O'CLOCK BELOW US. 'CLB XING CLB'. WE COULD NOT GET VISUAL CONTACT WITH THE INTRUDER, SO WE BEGAN A CLB. THE TCASII CALLED 'CLR OF CONFLICT' AT ABOUT 10400 FT. WE ADVISED ATC AS WE CLBED ON TCASII RA. HE INSTRUCTED US AFTER 'CLR OF CONFLICT' TO MAINTAIN 10000 FT. AS WE DSNDED TO 10000 WE RECEIVED ANOTHER TCASII ALERT 'TFC, TFC...DSND XING DSND'. WE GOT VISUAL CONTACT WITH THE INTRUDER AT 10200. IT WAS AT 10000 XING R TO L AT APPROX 3 MI. WE MAINTAINED VISUAL. WE ASKED ATC ABOUT THE TFC. HE CONFIRMED 'AT 10000, 11 O'CLOCK'. WE DSNDED TO 10000.

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.