Medium large transport crew ignored TCASII RA command and almost caused a disaster.

Attributes
ACN	257669
Time
Date	199311
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : atl
State Reference	GA
Altitude	msl bound lower : 9300 msl bound upper : 9800
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : atl
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
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 : first officer
Qualification	pilot : flight engineer pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 150 flight time total : 6000 flight time type : 1000
ASRS Report	257669
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : nmac non adherence : far
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Miss Distance	vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Climbing through 5000 ft, first officer flying the aircraft, was told by departure control to turn right to 360 degrees. We continued to climb to 10000 ft. At 8500 ft the aircraft's speed was 240 KIAS. 'Override 320 KIAS' was requested and selected on the flight guidance panel. As the nose was being lowered passing through 9300 ft, we observed and heard a 'traffic' TCASII advisory, followed immediately by a 'monitor vertical speed' which commanded a minimum rate of climb of 3000 FPM. This command was followed moments later by a 'climb, climb' audio command. A visual scan revealed only one aircraft at our 1 O'clock position inbound on the rome STAR. I informed atlanta departure control we were under an RA condition. Departure control informed us the target had been cleared to 11000 ft but he was 100 ft below that altitude. It was my judgement not to follow the TCASII guidance. I told my first officer to level off. The inbound aircraft passed 500 ft above us. I think that in aircraft problems with TCASII we now have, altitude separation between inbound and outbound aircraft be 2000 ft to prevent these 'pop-up' TCASII RA's.

Original NASA ASRS Text

Title: MLG CREW IGNORED TCASII RA COMMAND AND ALMOST CAUSED A DISASTER.

Narrative: CLBING THROUGH 5000 FT, FO FLYING THE ACFT, WAS TOLD BY DEP CTL TO TURN R TO 360 DEGS. WE CONTINUED TO CLB TO 10000 FT. AT 8500 FT THE ACFT'S SPD WAS 240 KIAS. 'OVERRIDE 320 KIAS' WAS REQUESTED AND SELECTED ON THE FLT GUIDANCE PANEL. AS THE NOSE WAS BEING LOWERED PASSING THROUGH 9300 FT, WE OBSERVED AND HEARD A 'TFC' TCASII ADVISORY, FOLLOWED IMMEDIATELY BY A 'MONITOR VERT SPD' WHICH COMMANDED A MINIMUM RATE OF CLB OF 3000 FPM. THIS COMMAND WAS FOLLOWED MOMENTS LATER BY A 'CLB, CLB' AUDIO COMMAND. A VISUAL SCAN REVEALED ONLY ONE ACFT AT OUR 1 O'CLOCK POS INBOUND ON THE ROME STAR. I INFORMED ATLANTA DEP CTL WE WERE UNDER AN RA CONDITION. DEP CTL INFORMED US THE TARGET HAD BEEN CLRED TO 11000 FT BUT HE WAS 100 FT BELOW THAT ALT. IT WAS MY JUDGEMENT NOT TO FOLLOW THE TCASII GUIDANCE. I TOLD MY FO TO LEVEL OFF. THE INBOUND ACFT PASSED 500 FT ABOVE US. I THINK THAT IN ACFT PROBS WITH TCASII WE NOW HAVE, ALT SEPARATION BTWN INBOUND AND OUTBOUND ACFT BE 2000 FT TO PREVENT THESE 'POP-UP' TCASII RA'S.

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.