Flight crew of an medium large transport descended off of assigned altitude in response to a TCASII ...

Attributes
ACN	333150
Time
Date	199604
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : aml airport : dca
State Reference	VA
Altitude	msl bound lower : 7800 msl bound upper : 8000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : dca
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	arrival other arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	other other : other pilot : atp pilot : flight engineer pilot : cfi
Experience	flight time last 90 days : 200 flight time total : 11655 flight time type : 980
ASRS Report	333150
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action flight crew : returned to intended course or assigned course
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other

Narrative:

We were on approach to washington national airport at 8000 ft MSL and just passed the aml VOR, when we got a RA on our TCASII. We were night IMC at the time of the RA. We got the RA without any TA information, we followed the TCASII indications to clear the conflict. We were at 8000 ft MSL TCASII commanded a descent, and descended about 200 ft and were clear of conflict. We advise dca approach we had a TCASII RA and had to descend. Dca approach said there was no traffic in the area, dca approach said only traffic was at FL230. Under the circumstances, we had to comply with the TCASII commands. At the same time dca approach issued a clearance to 3000 ft MSL and the flight continued without further incident. After the TCASII event, our assumption that it was a false RA, there never was a TA or clear of conflict announcement. Under our company procedures we acted correctly.

Original NASA ASRS Text

Title: FLC OF AN MLG DSNDED OFF OF ASSIGNED ALT IN RESPONSE TO A TCASII RA.

Narrative: WE WERE ON APCH TO WASHINGTON NATIONAL ARPT AT 8000 FT MSL AND JUST PASSED THE AML VOR, WHEN WE GOT A RA ON OUR TCASII. WE WERE NIGHT IMC AT THE TIME OF THE RA. WE GOT THE RA WITHOUT ANY TA INFO, WE FOLLOWED THE TCASII INDICATIONS TO CLR THE CONFLICT. WE WERE AT 8000 FT MSL TCASII COMMANDED A DSCNT, AND DSNDED ABOUT 200 FT AND WERE CLR OF CONFLICT. WE ADVISE DCA APCH WE HAD A TCASII RA AND HAD TO DSND. DCA APCH SAID THERE WAS NO TFC IN THE AREA, DCA APCH SAID ONLY TFC WAS AT FL230. UNDER THE CIRCUMSTANCES, WE HAD TO COMPLY WITH THE TCASII COMMANDS. AT THE SAME TIME DCA APCH ISSUED A CLRNC TO 3000 FT MSL AND THE FLT CONTINUED WITHOUT FURTHER INCIDENT. AFTER THE TCASII EVENT, OUR ASSUMPTION THAT IT WAS A FALSE RA, THERE NEVER WAS A TA OR CLR OF CONFLICT ANNOUNCEMENT. UNDER OUR COMPANY PROCS WE ACTED CORRECTLY.

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.

Flight crew of an medium large transport descended off of assigned altitude in response to a TCASII RA.