An air carrier A300 descended in response to a TCASII command. Altitude deviation.

Attributes
ACN	347980
Time
Date	199609
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : swl
State Reference	MD
Altitude	msl bound lower : 27200 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc
Operator	common carrier : air carrier
Make Model Name	A300
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
ASRS Report	347980
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	347979
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

Received TCASII RA to descend while cruising at FL280. Disconnected autoplt and initiated descent following guidance on vsi. Descended to FL272 before receiving clear of conflict. We then climbed back to FL280 and advised ATC. ATC replied that conflict was due to an air carrier jet descending to FL290. Although we were in VMC conditions, we never established visual contact with other aircraft.

Original NASA ASRS Text

Title: AN ACR A300 DSNDED IN RESPONSE TO A TCASII COMMAND. ALTDEV.

Narrative: RECEIVED TCASII RA TO DSND WHILE CRUISING AT FL280. DISCONNECTED AUTOPLT AND INITIATED DSCNT FOLLOWING GUIDANCE ON VSI. DSNDED TO FL272 BEFORE RECEIVING CLR OF CONFLICT. WE THEN CLBED BACK TO FL280 AND ADVISED ATC. ATC REPLIED THAT CONFLICT WAS DUE TO AN ACR JET DSNDING TO FL290. ALTHOUGH WE WERE IN VMC CONDITIONS, WE NEVER ESTABLISHED VISUAL CONTACT WITH OTHER ACFT.

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.