TCASII RA. - NASA ASRS

Attributes
ACN	276179
Time
Date	199407
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ctf
State Reference	SC
Altitude	msl bound lower : 9500 msl bound upper : 10000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx tower : pdk
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
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 : 30 flight time total : 24000 flight time type : 900
ASRS Report	276179
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 100 vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

We were cruising at our assigned altitude of 10000 ft. Traffic came from a 10 O'clock position also at 10000 ft straight at us. The TCASII system gave us an RA command to descend which we complied with by descending to 9500 ft. ATC never gave us this traffic. The frequency was very busy at the time we reported the descent as we started the descent. ATC then saw the traffic and we went back to our altitude of 10000 ft.

Original NASA ASRS Text

Title: TCASII RA.

Narrative: WE WERE CRUISING AT OUR ASSIGNED ALT OF 10000 FT. TFC CAME FROM A 10 O'CLOCK POS ALSO AT 10000 FT STRAIGHT AT US. THE TCASII SYS GAVE US AN RA COMMAND TO DSND WHICH WE COMPLIED WITH BY DSNDING TO 9500 FT. ATC NEVER GAVE US THIS TFC. THE FREQ WAS VERY BUSY AT THE TIME WE RPTED THE DSCNT AS WE STARTED THE DSCNT. ATC THEN SAW THE TFC AND WE WENT BACK TO OUR ALT OF 10000 FT.

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.