TCAS alert. - NASA ASRS

Attributes
ACN	169012
Time
Date	199101
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : hyp
State Reference	CA
Altitude	msl bound lower : 23000 msl bound upper : 24000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zoa
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other descent other
Route In Use	arrival star : star enroute airway : zoa
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
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 : 250 flight time total : 8800
ASRS Report	169012
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : overcame equipment problem
Consequence	Other
Miss Distance	vertical : 1000
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Aircraft was descending to FL240 and hyp 3 arrival. Outboard aircraft level at FL230 in sight for 20 mi. Our aircraft was passing FL250 with autoplt in altitude capture mode for FL240. TCAS announced, 'traffic,' followed by 'reduce descent,' with red and green command arcs on vsi. Aircraft autoplt was disengaged per prescribed procedures. This cancelled altitude arm for FL240 and it had to be rearmed. Aircraft was manually leveled at FL240 and traffic passed under nose at FL230 per ATC clearance. This was a nuisance RA by TCAS.

Original NASA ASRS Text

Title: TCAS ALERT.

Narrative: ACFT WAS DSNDING TO FL240 AND HYP 3 ARR. OUTBOARD ACFT LEVEL AT FL230 IN SIGHT FOR 20 MI. OUR ACFT WAS PASSING FL250 WITH AUTOPLT IN ALT CAPTURE MODE FOR FL240. TCAS ANNOUNCED, 'TFC,' FOLLOWED BY 'REDUCE DSNT,' WITH RED AND GREEN COMMAND ARCS ON VSI. ACFT AUTOPLT WAS DISENGAGED PER PRESCRIBED PROCS. THIS CANCELLED ALT ARM FOR FL240 AND IT HAD TO BE REARMED. ACFT WAS MANUALLY LEVELED AT FL240 AND TFC PASSED UNDER NOSE AT FL230 PER ATC CLRNC. THIS WAS A NUISANCE RA BY TCAS.

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.