TCASII RA provokes flight crew to evade intruding VFR traffic in IMC conditions.

Attributes
ACN	306853
Time
Date	199506
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : cyn airport : phl
State Reference	NJ
Altitude	msl bound lower : 10000 msl bound upper : 10500
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : phl
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Route In Use	departure other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Flight Phase	climbout : intermediate altitude
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 14000 flight time type : 200
ASRS Report	306853
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance non adherence : required legal separation 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 other
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 9000 vertical : 300
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

While departing phl nebound at 10000 ft (level) we encountered a TCASII RA, requiring evasive action, resulting in a climb out of our assigned altitude. We left 10000 ft MSL, cleared the conflict at 10500 ft, and descended back to 10000 ft MSL. Advised ATC of our actions. ATC stated that the aircraft was assigned VFR at 11500 ft MSL. At time of TCASII RA -- aircraft was 300 ft below and 1 1/2 mi to right of my aircraft, my aircraft was level at 10000 ft MSL. The intruder aircraft was operating illegally (VFR in actual IMC conditions) and was climbing through our altitude, in a heavily travelled northeast corridor in IMC.

Original NASA ASRS Text

Title: TCASII RA PROVOKES FLC TO EVADE INTRUDING VFR TFC IN IMC CONDITIONS.

Narrative: WHILE DEPARTING PHL NEBOUND AT 10000 FT (LEVEL) WE ENCOUNTERED A TCASII RA, REQUIRING EVASIVE ACTION, RESULTING IN A CLBOUT OF OUR ASSIGNED ALT. WE LEFT 10000 FT MSL, CLRED THE CONFLICT AT 10500 FT, AND DSNDED BACK TO 10000 FT MSL. ADVISED ATC OF OUR ACTIONS. ATC STATED THAT THE ACFT WAS ASSIGNED VFR AT 11500 FT MSL. AT TIME OF TCASII RA -- ACFT WAS 300 FT BELOW AND 1 1/2 MI TO R OF MY ACFT, MY ACFT WAS LEVEL AT 10000 FT MSL. THE INTRUDER ACFT WAS OPERATING ILLEGALLY (VFR IN ACTUAL IMC CONDITIONS) AND WAS CLBING THROUGH OUR ALT, IN A HEAVILY TRAVELLED NE CORRIDOR IN IMC.

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.