Pilot deviation from TCASII RA evasive action from unknown aircraft.

Attributes
ACN	293050
Time
Date	199501
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : dca
State Reference	DC
Altitude	msl bound lower : 8000 msl bound upper : 7600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dca
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise other
Route In Use	arrival other enroute airway : dca
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 170 flight time total : 4500 flight time type : 1500
ASRS Report	293050
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

It was a VFR day. We were on the irons arrival into dca at 8000 ft. We received a TA on TCASII. We spotted the traffic at 1 O'clock. TCASII revealed the traffic was at 8400 ft. The traffic was to pass over our aircraft. Then a RA appeared on TCASII to descend of at least 1500 FPM. As the PF I followed the RA. At 7600 ft the TCASII revealed we were clear of traffic, then we climbed back to 8000 ft. When we notified ATC of our traffic and subsequent deviation they issued a TA for the first time. There was no further incident on our arrival to dca.

Original NASA ASRS Text

Title: PLTDEV FROM TCASII RA EVASIVE ACTION FROM UNKNOWN ACFT.

Narrative: IT WAS A VFR DAY. WE WERE ON THE IRONS ARR INTO DCA AT 8000 FT. WE RECEIVED A TA ON TCASII. WE SPOTTED THE TFC AT 1 O'CLOCK. TCASII REVEALED THE TFC WAS AT 8400 FT. THE TFC WAS TO PASS OVER OUR ACFT. THEN A RA APPEARED ON TCASII TO DSND OF AT LEAST 1500 FPM. AS THE PF I FOLLOWED THE RA. AT 7600 FT THE TCASII REVEALED WE WERE CLR OF TFC, THEN WE CLBED BACK TO 8000 FT. WHEN WE NOTIFIED ATC OF OUR TFC AND SUBSEQUENT DEV THEY ISSUED A TA FOR THE FIRST TIME. THERE WAS NO FURTHER INCIDENT ON OUR ARR TO DCA.

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.