Altitude deviation altitude excursion when TCASII RA received from unknown VFR traffic in area.

Attributes
ACN	260945
Time
Date	199401
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : dqo
State Reference	DE
Altitude	msl bound lower : 15000 msl bound upper : 16200
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 60 flight time total : 8000 flight time type : 125
ASRS Report	260945
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : far non adherence : clearance non adherence : required legal separation other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 6000 vertical : 200
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

During arrival phase of flight at phl, level 15000 ft on vectors with excellent visibility, a TCASII TA was received. Crew attempted to sight traffic but no contact was made. A few seconds later a TCASII RA, commanding a greater than 2000 FPM climb, was received. The captain initiated an immediate climb towards the green arc. When TCASII called clear of traffic, the aircraft was leveled at 16200 ft. ATC was advised of our altitude deviation and the reason. We then descended back to our assigned altitude and continued the flight. Had ATC provided an early callout of the traffic, the crew might have been able to locate the traffic and avoid any abrupt maneuvers, however ATC claimed it was a pop-up target not in contact with any ATC facility.

Original NASA ASRS Text

Title: ALTDEV ALT EXCURSION WHEN TCASII RA RECEIVED FROM UNKNOWN VFR TFC IN AREA.

Narrative: DURING ARR PHASE OF FLT AT PHL, LEVEL 15000 FT ON VECTORS WITH EXCELLENT VISIBILITY, A TCASII TA WAS RECEIVED. CREW ATTEMPTED TO SIGHT TFC BUT NO CONTACT WAS MADE. A FEW SECONDS LATER A TCASII RA, COMMANDING A GREATER THAN 2000 FPM CLB, WAS RECEIVED. THE CAPT INITIATED AN IMMEDIATE CLB TOWARDS THE GREEN ARC. WHEN TCASII CALLED CLR OF TFC, THE ACFT WAS LEVELED AT 16200 FT. ATC WAS ADVISED OF OUR ALTDEV AND THE REASON. WE THEN DSNDED BACK TO OUR ASSIGNED ALT AND CONTINUED THE FLT. HAD ATC PROVIDED AN EARLY CALLOUT OF THE TFC, THE CREW MIGHT HAVE BEEN ABLE TO LOCATE THE TFC AND AVOID ANY ABRUPT MANEUVERS, HOWEVER ATC CLAIMED IT WAS A POP-UP TARGET NOT IN CONTACT WITH ANY ATC FACILITY.

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.