Near midair collision in traffic pattern at uncontrolled airport.

Attributes
ACN	247174
Time
Date	199307
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ll10
State Reference	IL
Altitude	msl bound lower : 1700 msl bound upper : 1700
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : bos
Operator	general aviation : instructional
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	other
Flight Plan	VFR
Aircraft 2
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	other
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial pilot : cfi pilot : private
Experience	flight time last 90 days : 100 flight time total : 530 flight time type : 10
ASRS Report	247174
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Events
Anomaly	conflict : nmac non adherence : far non adherence : published procedure other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 300 vertical : 100
Supplementary
Primary Problem	Flight Crew Human Performance

Narrative:

I was acting as the safety pilot en route from arrival to 1c5. Descending from 3000 MSL to traffic pattern altitude at 1c5, while monitoring 122.9, the CTAF for naper airport and 1c5, I idented another aircraft. The other aircraft I believe was an small aircraft single engine land Y at approximately 1500 MSL at our 10 O'clock position. The small aircraft Y was on left downwind for 36 at naper aeronautical. When I idented the small aircraft Y I immediately turned to the right to avoid the aircraft. After we turned to avoid the small aircraft Y we heard it report base for 36. We never heard the small aircraft Y report downwind, which I believe would have nullified the near miss all together.

Original NASA ASRS Text

Title: NMAC IN TFC PATTERN AT UNCTLED ARPT.

Narrative: I WAS ACTING AS THE SAFETY PLT ENRTE FROM ARR TO 1C5. DSNDING FROM 3000 MSL TO TFC PATTERN ALT AT 1C5, WHILE MONITORING 122.9, THE CTAF FOR NAPER ARPT AND 1C5, I IDENTED ANOTHER ACFT. THE OTHER ACFT I BELIEVE WAS AN SMA SINGLE ENG LAND Y AT APPROX 1500 MSL AT OUR 10 O'CLOCK POS. THE SMA Y WAS ON L DOWNWIND FOR 36 AT NAPER AERO. WHEN I IDENTED THE SMA Y I IMMEDIATELY TURNED TO THE R TO AVOID THE ACFT. AFTER WE TURNED TO AVOID THE SMA Y WE HEARD IT RPT BASE FOR 36. WE NEVER HEARD THE SMA Y RPT DOWNWIND, WHICH I BELIEVE WOULD HAVE NULLIFIED THE NEAR MISS ALL TOGETHER.

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.