Light transport air carrier on descent to ILS had close proximity with VFR traffic. TCASII RA.

Attributes
ACN	253691
Time
Date	199310
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : phl
State Reference	PA
Altitude	msl bound lower : 3500 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : phl tower : ilg
Operator	common carrier : air carrier
Make Model Name	Light Transport
Flight Phase	descent 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 : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 2638 flight time type : 200
ASRS Report	253691
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We had been assigned a heading to intercept the ILS 17 localizer at phl. Once established on the localizer inbound, and at approximately 20 DME, ATC issued instructions to descend from 4000 ft MSL to and maintain 3000 ft. At 3700 ft MSL, ATC advised us to stop descent at 3500 ft due to VFR traffic at '12 O'clock indicating 3000 ft.' traffic was not in sight and neither were 3 other aircraft on TCASII. Upon leveling at 3500 ft MSL an RA of 'climb, climb' (1500 FPM) occurred and was immediately initiated. At 4000 ft 'clear of conflict' sounded. ATC was notified of RA, and descent back to 3500 ft was begun. ATC responded that the traffic had already been pointed out as the 'VFR traffic at 3000 ft.' captain responded by stating that we received an RA and that it was mandatory for us to initiate the climb. Visual approach to runway 17 was then continued with no further occurrences. I feel we should not have been instructed to descend with VFR traffic ahead, or traffic should have been pointed out first so visual separation could have been maintained.

Original NASA ASRS Text

Title: LTT ACR ON DSCNT TO ILS HAD CLOSE PROX WITH VFR TFC. TCASII RA.

Narrative: WE HAD BEEN ASSIGNED A HDG TO INTERCEPT THE ILS 17 LOC AT PHL. ONCE ESTABLISHED ON THE LOC INBOUND, AND AT APPROX 20 DME, ATC ISSUED INSTRUCTIONS TO DSND FROM 4000 FT MSL TO AND MAINTAIN 3000 FT. AT 3700 FT MSL, ATC ADVISED US TO STOP DSCNT AT 3500 FT DUE TO VFR TFC AT '12 O'CLOCK INDICATING 3000 FT.' TFC WAS NOT IN SIGHT AND NEITHER WERE 3 OTHER ACFT ON TCASII. UPON LEVELING AT 3500 FT MSL AN RA OF 'CLB, CLB' (1500 FPM) OCCURRED AND WAS IMMEDIATELY INITIATED. AT 4000 FT 'CLR OF CONFLICT' SOUNDED. ATC WAS NOTIFIED OF RA, AND DSCNT BACK TO 3500 FT WAS BEGUN. ATC RESPONDED THAT THE TFC HAD ALREADY BEEN POINTED OUT AS THE 'VFR TFC AT 3000 FT.' CAPT RESPONDED BY STATING THAT WE RECEIVED AN RA AND THAT IT WAS MANDATORY FOR US TO INITIATE THE CLB. VISUAL APCH TO RWY 17 WAS THEN CONTINUED WITH NO FURTHER OCCURRENCES. I FEEL WE SHOULD NOT HAVE BEEN INSTRUCTED TO DSND WITH VFR TFC AHEAD, OR TFC SHOULD HAVE BEEN POINTED OUT FIRST SO VISUAL SEPARATION COULD HAVE BEEN MAINTAINED.

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.