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Close proximity GA small aircraft on IAP ILS approach and a second small aircraft in traffic pattern for crossing runway. Airport was IFR at the time.
| Attributes | |
| ACN | 136137 |
| Time | |
| Date | 199002 |
| Day | Sun |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : cwa |
| State Reference | WI |
| Altitude | msl bound lower : 2000 msl bound upper : 2000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zmp tower : lax |
| Operator | general aviation : instructional |
| Make Model Name | Small Aircraft, High Wing, 1 Eng, Fixed Gear |
| Flight Phase | descent : approach landing other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | Small Aircraft, High Wing, 1 Eng, Fixed Gear |
| Flight Phase | other |
| Flight Plan | VFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : single pilot |
| Qualification | pilot : instrument pilot : cfi pilot : commercial |
| Experience | flight time last 90 days : 20 flight time total : 960 flight time type : 450 |
| ASRS Report | 136137 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : single pilot |
| Events | |
| Anomaly | conflict : airborne less severe inflight encounter : vfr in imc non adherence : far |
| Independent Detector | other flight crewa |
| Resolutory Action | none taken : insufficient time |
| Consequence | Other |
| Miss Distance | horizontal : 6000 vertical : 300 |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
While flying on final approach on an IFR flight with a control zone reported as 3/4 mi visibility in fog, and a flight visibility of 5MI, an small aircraft Y crossed in front and above the final. The pilot reported a downwind for the runway 17. I radioed that the airport was IFR. The pilot responds that he could see 3-4 mi. I completed the approach and landed and parked. The other pilot landed parked. A discussion with the other pilot revealed he read the hourly report from the WX motion computer as '3/4 F,' meaning 3-4 mi. He was surprised to learn that '3/4 F' means 3/4 mi visibility. I believe the pilot's misunderstanding of the reported WX and understanding of control zones contributed to this event. I have reviewed the requirements for operating in a control zone for VFR and SVFR, how to read an hourly WX report for sky and ceiling and referred him to the far's re: VFR operations and VFR in a control zone.
Original NASA ASRS Text
Title: CLOSE PROX GA SMA ON IAP ILS APCH AND A SECOND SMA IN TRAFFIC PATTERN FOR CROSSING RWY. ARPT WAS IFR AT THE TIME.
Narrative: WHILE FLYING ON FINAL APCH ON AN IFR FLT WITH A CTL ZONE RPTED AS 3/4 MI VISIBILITY IN FOG, AND A FLT VISIBILITY OF 5MI, AN SMA Y CROSSED IN FRONT AND ABOVE THE FINAL. THE PLT RPTED A DOWNWIND FOR THE RWY 17. I RADIOED THAT THE ARPT WAS IFR. THE PLT RESPONDS THAT HE COULD SEE 3-4 MI. I COMPLETED THE APCH AND LANDED AND PARKED. THE OTHER PLT LANDED PARKED. A DISCUSSION WITH THE OTHER PLT REVEALED HE READ THE HOURLY RPT FROM THE WX MOTION COMPUTER AS '3/4 F,' MEANING 3-4 MI. HE WAS SURPRISED TO LEARN THAT '3/4 F' MEANS 3/4 MI VISIBILITY. I BELIEVE THE PLT'S MISUNDERSTANDING OF THE RPTED WX AND UNDERSTANDING OF CTL ZONES CONTRIBUTED TO THIS EVENT. I HAVE REVIEWED THE REQUIREMENTS FOR OPERATING IN A CTL ZONE FOR VFR AND SVFR, HOW TO READ AN HRLY WX RPT FOR SKY AND CEILING AND REFERRED HIM TO THE FAR'S RE: VFR OPS AND VFR IN A CTL ZONE.
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.