A TCASII RA may have resulted from equipment design logic problems. Flight crew responded.

Attributes
ACN	318996
Time
Date	199510
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : chk airport : hnl
State Reference	HI
Altitude	msl bound lower : 7300 msl bound upper : 7300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : hnl
Operator	common carrier : air carrier
Make Model Name	DC-10 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	descent : approach descent other
Route In Use	enroute : on vectors enroute other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial
Experience	flight time last 90 days : 235 flight time total : 9500
ASRS Report	318996
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 240 flight time total : 30000
ASRS Report	318987
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action other
Consequence	Other
Miss Distance	horizontal : 0 vertical : 500
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

On downwind to hnl on radar vector heading 170 degrees assigned, we had a TCASII resolution. First command 'slow rate of descent,' then 'climb, climb.' crew responded immediately and TCASII responded 'conflict resolved.' we were at 7300 ft MSL and display showed a 1200 ft below aircraft at our 9 O'clock position, then went to 500 ft and then resolved with a spinning motion of display. Could have been spurious input. Supplemental information from acn 318987: first officer was flying and pulling back on the yoke while applying power. TCASII went solid red so I grabbed the yoke and pulled 'firm' back pressure until we heard 'clear of conflict.' we looked outside but never had a visual target.

Original NASA ASRS Text

Title: A TCASII RA MAY HAVE RESULTED FROM EQUIP DESIGN LOGIC PROBS. FLC RESPONDED.

Narrative: ON DOWNWIND TO HNL ON RADAR VECTOR HDG 170 DEGS ASSIGNED, WE HAD A TCASII RESOLUTION. FIRST COMMAND 'SLOW RATE OF DSCNT,' THEN 'CLB, CLB.' CREW RESPONDED IMMEDIATELY AND TCASII RESPONDED 'CONFLICT RESOLVED.' WE WERE AT 7300 FT MSL AND DISPLAY SHOWED A 1200 FT BELOW ACFT AT OUR 9 O'CLOCK POS, THEN WENT TO 500 FT AND THEN RESOLVED WITH A SPINNING MOTION OF DISPLAY. COULD HAVE BEEN SPURIOUS INPUT. SUPPLEMENTAL INFO FROM ACN 318987: FO WAS FLYING AND PULLING BACK ON THE YOKE WHILE APPLYING PWR. TCASII WENT SOLID RED SO I GRABBED THE YOKE AND PULLED 'FIRM' BACK PRESSURE UNTIL WE HEARD 'CLR OF CONFLICT.' WE LOOKED OUTSIDE BUT NEVER HAD A VISUAL TARGET.

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.