Potential conflict created by a heading track deviation.

Attributes
ACN	274125
Time
Date	199406
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : phl
State Reference	PA
Altitude	msl bound lower : 3000 msl bound upper : 3000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : phl
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : phl
Flight Phase	cruise other descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 15000 flight time type : 4500
ASRS Report	274125
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical conflict : airborne less severe inflight encounter other non adherence : required legal separation non adherence : clearance other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance flight crew : took evasive action other
Consequence	Other
Miss Distance	horizontal : 3000 vertical : 300
Supplementary
Primary Problem	Airport
Air Traffic Incident	Pilot Deviation
Situations
ATC Facility	other physical facility

Narrative:

On approach to phl international airport (737-300), visibility about 3 mi with haze, on a vector to intercept final approach for ILS runway 27R. Both pilots lost ILS reception signal for about 2 mins. It was not apparent immediately, until approach asked us where we were heading. We had flown past localizer course. He asked us if we could see the field, we said yes we could just barely make it out, so we made a visual to runway 27R from that point. As we were turning toward runway 27R at phl, we received a TCASII event telling us to climb immediately, and we did just that. After that we resumed the approach to runway 27R.

Original NASA ASRS Text

Title: POTENTIAL CONFLICT CREATED BY A HDG TRACK DEV.

Narrative: ON APCH TO PHL INTL ARPT (737-300), VISIBILITY ABOUT 3 MI WITH HAZE, ON A VECTOR TO INTERCEPT FINAL APCH FOR ILS RWY 27R. BOTH PLTS LOST ILS RECEPTION SIGNAL FOR ABOUT 2 MINS. IT WAS NOT APPARENT IMMEDIATELY, UNTIL APCH ASKED US WHERE WE WERE HEADING. WE HAD FLOWN PAST LOC COURSE. HE ASKED US IF WE COULD SEE THE FIELD, WE SAID YES WE COULD JUST BARELY MAKE IT OUT, SO WE MADE A VISUAL TO RWY 27R FROM THAT POINT. AS WE WERE TURNING TOWARD RWY 27R AT PHL, WE RECEIVED A TCASII EVENT TELLING US TO CLB IMMEDIATELY, AND WE DID JUST THAT. AFTER THAT WE RESUMED THE APCH TO RWY 27R.

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.