A B727-200 crew in cruise, responded to a descend RA from TCASII.

Attributes
ACN	500269
Time
Date	200102
Day	Fri
Local Time Of Day	0001 To 0600
Place
Locale Reference	navaid : igb.vortac
State Reference	MS
Altitude	msl bound lower : 27900 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zme.artcc
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Navigation In Use	other vortac
Flight Phase	cruise : level
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zme.artcc
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	descent : vacating altitude
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : instrument pilot : flight engineer pilot : atp pilot : multi engine
Experience	flight time last 90 days : 150 flight time total : 4200 flight time type : 250
ASRS Report	500269
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : instrument pilot : multi engine pilot : private pilot : atp pilot : commercial
Experience	flight time last 90 days : 50 flight time total : 5000 flight time type : 1500
ASRS Report	500120
Events
Anomaly	conflict : airborne critical
Independent Detector	aircraft equipment : tcas other flight crewa
Resolutory Action	flight crew : took evasive action
Miss Distance	vertical : 600
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft ATC Human Performance
Primary Problem	Aircraft

Narrative:

Flying at FL280, en route from ind to msy, we received a TCASII alert. TCASII alert consisted of a traffic call followed by a descend call. Captain started evasive action by disconnecting the autoplt and beginning a descent. ATC was notified of the RA. As the descent was initiated the first officer gained visual contact with the other aircraft. Aircraft was off our right side approximately 600 ft above and then it descended through our altitude. Once visual contact was gained altitude deviation stopped, total deviation consisted of 100 ft below assigned. Traffic was reported to ATC, but ATC said no traffic was in the area. ATC asked if we wanted to file a UFO report. Captain told ATC that it was definitely an aircraft, at which time ATC asked the captain about filing an near midair collision report.

Original NASA ASRS Text

Title: A B727-200 CREW IN CRUISE, RESPONDED TO A DSND RA FROM TCASII.

Narrative: FLYING AT FL280, ENRTE FROM IND TO MSY, WE RECEIVED A TCASII ALERT. TCASII ALERT CONSISTED OF A TFC CALL FOLLOWED BY A DSND CALL. CAPT STARTED EVASIVE ACTION BY DISCONNECTING THE AUTOPLT AND BEGINNING A DSCNT. ATC WAS NOTIFIED OF THE RA. AS THE DSCNT WAS INITIATED THE FO GAINED VISUAL CONTACT WITH THE OTHER ACFT. ACFT WAS OFF OUR R SIDE APPROX 600 FT ABOVE AND THEN IT DSNDED THROUGH OUR ALT. ONCE VISUAL CONTACT WAS GAINED ALTDEV STOPPED, TOTAL DEV CONSISTED OF 100 FT BELOW ASSIGNED. TFC WAS RPTED TO ATC, BUT ATC SAID NO TFC WAS IN THE AREA. ATC ASKED IF WE WANTED TO FILE A UFO RPT. CAPT TOLD ATC THAT IT WAS DEFINITELY AN ACFT, AT WHICH TIME ATC ASKED THE CAPT ABOUT FILING AN NMAC RPT.

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.