Narrative:

Listened to ATIS 20 miles out and prevailing wind favored runway 21. Was on a left downwind for 21 when listened to ATIS again and wind was now 020 at 9 KTS. Decided to cross over midfield and enter a downwind for 3. [I] made the call on the radio [and] made another call when over midfield. At that time; saw a piper fly underneath from the runway 21 direction. It passed about 200 ft below. Suspected it was performing a low; IFR practice approach. Wondered why I never heard the piper on CTAF. Checked my comm 1 radio and noted the volume was all the way down. [I] had forgotten to turn the volume back up after an earlier discussion with my passengers. [I] then entered a left downwind for 3 with no issues. [I] never heard anything from the piper aircraft. Suspect he tuned back to ATC after his missed approach.

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Original NASA ASRS Text

Title: C172 pilot reports a NMAC with a Piper while over flying the HBI airport at 2;000 FT using CTAF procedures. The reporter discovers his radio volume has been turned down to talk with passengers and not returned to a listenable level.

Narrative: Listened to ATIS 20 miles out and prevailing wind favored Runway 21. Was on a left downwind for 21 when listened to ATIS again and wind was now 020 at 9 KTS. Decided to cross over midfield and enter a downwind for 3. [I] made the call on the radio [and] made another call when over midfield. At that time; saw a Piper fly underneath from the Runway 21 direction. It passed about 200 FT below. Suspected it was performing a low; IFR practice approach. Wondered why I never heard the Piper on CTAF. Checked my Comm 1 radio and noted the volume was all the way down. [I] had forgotten to turn the volume back up after an earlier discussion with my passengers. [I] then entered a left downwind for 3 with no issues. [I] never heard anything from the Piper aircraft. Suspect he tuned back to ATC after his missed approach.

Data retrieved from NASA's ASRS site as of July 2013 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.