Medium large transport has TCASII RA to climb. Traffic in sight, remains at altitude.

Attributes
ACN	220732
Time
Date	199209
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : mod
State Reference	CA
Altitude	msl bound lower : 17000 msl bound upper : 18000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent other
Route In Use	enroute airway : zoa
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument pilot : atp
Experience	flight time last 90 days : 150 flight time total : 8000 flight time type : 150
ASRS Report	220732
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 3000 vertical : 1000
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

TCASII TA was given for an aircraft that was in a climb to 17000 ft. We were level at FL180 with the aircraft in sight. The aircraft never appeared to be a threat and remained in sight at all times. A RA of 'climb, climb' was given when the TCASII showed the aircraft 900 ft below. No evasive action was taken because he appeared to be no threat and the TCASII was intermittently showing his altitude at 1000 ft +/- 100 ft below us. The other aircraft passed safely from right to left approximately 1/2 mi at closest point. Controller couldn't figure out why we got an RA and neither could we.

Original NASA ASRS Text

Title: MLG HAS TCASII RA TO CLB. TFC IN SIGHT, REMAINS AT ALT.

Narrative: TCASII TA WAS GIVEN FOR AN ACFT THAT WAS IN A CLB TO 17000 FT. WE WERE LEVEL AT FL180 WITH THE ACFT IN SIGHT. THE ACFT NEVER APPEARED TO BE A THREAT AND REMAINED IN SIGHT AT ALL TIMES. A RA OF 'CLB, CLB' WAS GIVEN WHEN THE TCASII SHOWED THE ACFT 900 FT BELOW. NO EVASIVE ACTION WAS TAKEN BECAUSE HE APPEARED TO BE NO THREAT AND THE TCASII WAS INTERMITTENTLY SHOWING HIS ALT AT 1000 FT +/- 100 FT BELOW US. THE OTHER ACFT PASSED SAFELY FROM R TO L APPROX 1/2 MI AT CLOSEST POINT. CTLR COULDN'T FIGURE OUT WHY WE GOT AN RA AND NEITHER COULD WE.

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.