Medium large transport has near midair collision with an aircraft while taking evasive action indica...

Attributes
ACN	235527
Time
Date	199303
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : phl
State Reference	PA
Altitude	msl bound lower : 7000 msl bound upper : 7800
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : phl
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
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	cruise other
Flight Plan	VFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 130 flight time total : 10500 flight time type : 6000
ASRS Report	235527
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : atp pilot : commercial
Events
Anomaly	conflict : nmac inflight encounter : vfr in imc non adherence : far other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	controller : issued new clearance flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 0 vertical : 400
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

While level at 7000 ft being vectored for ILS 27R, phl approach issued TA. We were just in and out of cloud bases and were unable to see the aircraft. At this time there was no TCASII target displayed. Approach issued a second TA, again no visual contact or TCASII target. Traffic altitude was reported as 6500 ft. Several seconds following second advisory, a TCASII 'climb, climb, now' RA was received. Simultaneous with the RA was phl approach suggestion to climb. We advised that we had an RA and were climbing. 'Clear of conflict' was announced as we passed 7600 ft and climb topped at 7800 ft, we descended back to 7000 ft. Closest point was 400 ft vertical as shown on TCASII. TCASII worked perfectly! The probable cause of this incident was the VFR aircraft continued flight into IMC. There was not a clearly defined cloud base so there could not be an accurate means of selecting a VFR altitude. Another mix of IFR traffic with VFR targets causing near misses.

Original NASA ASRS Text

Title: MLG HAS NMAC WITH AN ACFT WHILE TAKING EVASIVE ACTION INDICATED BY TCASII RA.

Narrative: WHILE LEVEL AT 7000 FT BEING VECTORED FOR ILS 27R, PHL APCH ISSUED TA. WE WERE JUST IN AND OUT OF CLOUD BASES AND WERE UNABLE TO SEE THE ACFT. AT THIS TIME THERE WAS NO TCASII TARGET DISPLAYED. APCH ISSUED A SECOND TA, AGAIN NO VISUAL CONTACT OR TCASII TARGET. TFC ALT WAS RPTED AS 6500 FT. SEVERAL SECONDS FOLLOWING SECOND ADVISORY, A TCASII 'CLB, CLB, NOW' RA WAS RECEIVED. SIMULTANEOUS WITH THE RA WAS PHL APCH SUGGESTION TO CLB. WE ADVISED THAT WE HAD AN RA AND WERE CLBING. 'CLR OF CONFLICT' WAS ANNOUNCED AS WE PASSED 7600 FT AND CLB TOPPED AT 7800 FT, WE DSNDED BACK TO 7000 FT. CLOSEST POINT WAS 400 FT VERT AS SHOWN ON TCASII. TCASII WORKED PERFECTLY! THE PROBABLE CAUSE OF THIS INCIDENT WAS THE VFR ACFT CONTINUED FLT INTO IMC. THERE WAS NOT A CLRLY DEFINED CLOUD BASE SO THERE COULD NOT BE AN ACCURATE MEANS OF SELECTING A VFR ALT. ANOTHER MIX OF IFR TFC WITH VFR TARGETS CAUSING NEAR MISSES.

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.

Medium large transport has near midair collision with an aircraft while taking evasive action indicated by TCASII RA.