Narrative:

Approximately 1 NM southeast of bands; descending from 8;000 MSL; heading approximately 210; I noticed a small plane (C-172) at my 10-o'clock; I was at the other plane's 2-o'clock (other aircraft was on my left; drawing right). I estimate distance was approximately 250 feet with vertical separation of approximate 10 feet with other aircraft slightly higher than me. The other aircraft had landing light on; I could see 2 occupants in front seats. I immediately put nose down and pulled power. After approximately 1-2 seconds; I glanced up through sun roof and saw the tail of the other aircraft briefly pass behind my right shoulder. I leveled off; added power and returned to my descent profile. The other aircraft was difficult to see against a busy ground/surface area until it was larger (closer). I was on day-2 and hour-3 of a 3.5-hour flight from ZZZ. My plane is stick/rudder with no auto-pilot; fatigue was likely a factor. I was on 'high alert' for traffic coming into busy ca airspace. I have ads-B-in only but highly prefer visual scan outside the cockpit. After the incident I glanced at my ads-B display and did not see the other aircraft. I immediately resumed my visual scan outside the cockpit. Last second visual contact with other aircraft at my 10-o'clock. It did not appear that the other aircraft either saw me or took evasive action; but I cannot confirm. I did not believe I was flying inappropriately (speed; altitude; airspace) and resumed my descent profile. Approximately 1-minute after the incident I turned on my landing light and broadcast a position report on bng CTAF. More broadly; I do not have a transponder and do not pick up flight following. I did not file a flight plan. I was in good health; good spirits; [and] looking forward to landing and seeing friends at L18. I had a minor case of gout (arthritis) in my left foot but had not taken any medication on the day of or days before the incident. In ZZZ; the night before; I had 2 glasses of wine with my dad; who is also a pilot. I had an opportunity to detail/discuss my flight plan with my dad the previous night and had flown this route one time 1-year prior. I am fitting my plane with ads-B out in march. When in high traffic areas I will turn on my landing light and give routine (5-minute) position reports. With new transponder I plan to pick up flight following and file flight plans for all cross country flights.

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Original NASA ASRS Text

Title: GA pilot reported experiencing an NMAC during descent to L18 airport.

Narrative: Approximately 1 NM SE of BANDS; descending from 8;000 MSL; heading approximately 210; I noticed a small plane (C-172) at my 10-o'clock; I was at the other plane's 2-o'clock (other aircraft was on my left; drawing right). I estimate distance was approximately 250 feet with vertical separation of approximate 10 feet with other aircraft slightly higher than me. The other aircraft had landing light on; I could see 2 occupants in front seats. I immediately put nose down and pulled power. After approximately 1-2 seconds; I glanced up through sun roof and saw the tail of the other aircraft briefly pass behind my right shoulder. I leveled off; added power and returned to my descent profile. The other aircraft was difficult to see against a busy ground/surface area until it was larger (closer). I was on day-2 and hour-3 of a 3.5-hour flight from ZZZ. My plane is stick/rudder with no auto-pilot; fatigue was likely a factor. I was on 'high alert' for traffic coming into busy CA airspace. I have ADS-B-IN only but highly prefer visual scan outside the cockpit. After the incident I glanced at my ADS-B display and did not see the other aircraft. I immediately resumed my visual scan outside the cockpit. Last second visual contact with other aircraft at my 10-o'clock. It did not appear that the other aircraft either saw me or took evasive action; but I cannot confirm. I did not believe I was flying inappropriately (speed; altitude; airspace) and resumed my descent profile. Approximately 1-minute after the incident I turned on my landing light and broadcast a position report on BNG CTAF. More broadly; I do not have a transponder and do not pick up flight following. I did not file a flight plan. I was in good health; good spirits; [and] looking forward to landing and seeing friends at L18. I had a minor case of gout (arthritis) in my left foot but had not taken any medication on the day of or days before the incident. In ZZZ; the night before; I had 2 glasses of wine with my dad; who is also a pilot. I had an opportunity to detail/discuss my flight plan with my dad the previous night and had flown this route one time 1-year prior. I am fitting my plane with ADS-B out in March. When in high traffic areas I will turn on my landing light and give routine (5-minute) position reports. With new transponder I plan to pick up flight following and file flight plans for all cross country flights.

Data retrieved from NASA's ASRS site 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.