Small aircraft helicopter, in cruise, crosses a localizer above glide slope, but has near midair col...

Attributes
ACN	123431
Time
Date	198909
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ugn
State Reference	IL
Altitude	msl bound lower : 2700 msl bound upper : 2700
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : ugn
Operator	general aviation : corporate
Make Model Name	Helicopter
Flight Phase	cruise other
Flight Plan	VFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Light Transport
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : atp
Experience	flight time last 90 days : 115 flight time total : 6500 flight time type : 2400
ASRS Report	123431
Person 2
Affiliation	company : air carrier
Function	oversight : pic
Events
Anomaly	conflict : nmac
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 200 vertical : 0
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

Flying off shore over lake michigan en route from mke to chicago cgx. VFR in hazy conditions (+/- 4 NM). Knowing our flight path would take us across the ugn localizer, I elected to fly above the G/south altitude to avoid any inbound aircraft. At 2700' MSL, 6 NM (reference LORAN) from the airport, we had to make a sudden deviation to avoid an light transport inbound on the localizer. He saw us at the same time, and also turned to avoid a collision. We were monitoring both approach and the control tower, but were not talking to either. We knew from monitoring radios that the light transport was inbound, but assumed he would be below us on the G/south (below 2200' MSL at that point of the approach). He was apparently flying the localizer inbound and maintaining altitude to circle for landing. We missed that part of the radio conversation, if it was indeed what transpired. By assuming that he was on the G/south, we set ourselves and him up for a midair. Reduced visibility made it difficult to see any aircraft that day. We often fly the lakeshore VFR west/O communicating with approach because of heavy traffic and radio congestion in the chicago area. The situation discourages VFR aircraft from using ATC for traffic avoidance.

Original NASA ASRS Text

Title: SMA HELICOPTER, IN CRUISE, CROSSES A LOCALIZER ABOVE GLIDE SLOPE, BUT HAS NMAC WITH ACR LTT INBOUND ON CIRCLE-TO-LAND.

Narrative: FLYING OFF SHORE OVER LAKE MICHIGAN ENRTE FROM MKE TO CHICAGO CGX. VFR IN HAZY CONDITIONS (+/- 4 NM). KNOWING OUR FLT PATH WOULD TAKE US ACROSS THE UGN LOC, I ELECTED TO FLY ABOVE THE G/S ALT TO AVOID ANY INBND ACFT. AT 2700' MSL, 6 NM (REF LORAN) FROM THE ARPT, WE HAD TO MAKE A SUDDEN DEVIATION TO AVOID AN LTT INBND ON THE LOC. HE SAW US AT THE SAME TIME, AND ALSO TURNED TO AVOID A COLLISION. WE WERE MONITORING BOTH APCH AND THE CTL TWR, BUT WERE NOT TALKING TO EITHER. WE KNEW FROM MONITORING RADIOS THAT THE LTT WAS INBND, BUT ASSUMED HE WOULD BE BELOW US ON THE G/S (BELOW 2200' MSL AT THAT POINT OF THE APCH). HE WAS APPARENTLY FLYING THE LOC INBND AND MAINTAINING ALT TO CIRCLE FOR LNDG. WE MISSED THAT PART OF THE RADIO CONVERSATION, IF IT WAS INDEED WHAT TRANSPIRED. BY ASSUMING THAT HE WAS ON THE G/S, WE SET OURSELVES AND HIM UP FOR A MIDAIR. REDUCED VISIBILITY MADE IT DIFFICULT TO SEE ANY ACFT THAT DAY. WE OFTEN FLY THE LAKESHORE VFR W/O COMMUNICATING WITH APCH BECAUSE OF HVY TFC AND RADIO CONGESTION IN THE CHICAGO AREA. THE SITUATION DISCOURAGES VFR ACFT FROM USING ATC FOR TFC AVOIDANCE.

Data retrieved from NASA's ASRS site as of August 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.

Small aircraft helicopter, in cruise, crosses a localizer above glide slope, but has near midair collision with air carrier light transport inbound on circle-to-land.