Large transport flight crew receives TCASII RA. Complies.

Attributes
ACN	176584
Time
Date	199104
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : enl
State Reference	IL
Altitude	msl bound lower : 27500 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zkc
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 220 flight time total : 23000 flight time type : 450
ASRS Report	176584
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : atp pilot : commercial
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
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 1500 vertical : 1000
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

While climbing to our assigned altitude of FL390 we were held down at FL280 for traffic. A short time later TCAS announced 'traffic'. Our TCAS screen displayed descending traffic between 11-12 O'clock, colored yellow. TCAS then announced 'descend', the screen symbol turned red and a red arc (descending) followed by a green arc at about 1000 FPM on the ivsi. The autoplt was disconnected and a descent initiated. After the threat passed we immediately climbed back to FL280. Total altitude change was less than 500'. We were unable to immediately advise ATC due to frequency congestion. When we were able to communication and advise of our actions, ATC advised that the aircraft in question was descending to FL290 from FL310. Our TCAS indicated the traffic at FL290. No visibility contact was established as we were flying directly into sun. Controller speculated that the 'threat' aircraft may have been descending 'rapidly' from FL310 to FL290. It was both pilots first experience with a RA.

Original NASA ASRS Text

Title: LGT FLT CREW RECEIVES TCASII RA. COMPLIES.

Narrative: WHILE CLBING TO OUR ASSIGNED ALT OF FL390 WE WERE HELD DOWN AT FL280 FOR TFC. A SHORT TIME LATER TCAS ANNOUNCED 'TFC'. OUR TCAS SCREEN DISPLAYED DSNDING TFC BTWN 11-12 O'CLOCK, COLORED YELLOW. TCAS THEN ANNOUNCED 'DSND', THE SCREEN SYMBOL TURNED RED AND A RED ARC (DSNDING) FOLLOWED BY A GREEN ARC AT ABOUT 1000 FPM ON THE IVSI. THE AUTOPLT WAS DISCONNECTED AND A DSNT INITIATED. AFTER THE THREAT PASSED WE IMMEDIATELY CLBED BACK TO FL280. TOTAL ALT CHANGE WAS LESS THAN 500'. WE WERE UNABLE TO IMMEDIATELY ADVISE ATC DUE TO FREQ CONGESTION. WHEN WE WERE ABLE TO COM AND ADVISE OF OUR ACTIONS, ATC ADVISED THAT THE ACFT IN QUESTION WAS DSNDING TO FL290 FROM FL310. OUR TCAS INDICATED THE TFC AT FL290. NO VIS CONTACT WAS ESTABLISHED AS WE WERE FLYING DIRECTLY INTO SUN. CTLR SPECULATED THAT THE 'THREAT' ACFT MAY HAVE BEEN DSNDING 'RAPIDLY' FROM FL310 TO FL290. IT WAS BOTH PLTS FIRST EXPERIENCE WITH A RA.

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.