Date: 201904
Local time of day: 1201-1800
Location: F70.Airport, CA
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Small Aircraft; High Wing; 1 Eng; Retractable Gear
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Initial Climb
Airspace: Class G F70
ATC / advisory: CTAF F70
Second aircraft: PA-28R Cherokee Arrow All Series
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Private; Flight Crew Instrument
Human factors: Situational Awareness; Communication Breakdown
Anomaly: Conflict NMAC; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: I was departing F70 Runway 18. At engine start; monitoring CTAF; there was a Cessna 172 in left closed traffic that has just departed Runway 18. At the run-up area there was a Cessna 150 completing run-up. An R22 helicopter then announced making a mid-field left downwind departure from Runway 18. The Cessna 172 announced turning final for Runway 18; and then landed. The R22 helicopter later announced being clear of the traffic pattern area to the northeast. The Cessna 150 then entered Runway 18 for a left downwind departure. When the Cessna 150 was well established his the upwind leg; I announced my departure from Runway 18 with a left downwind and northeast departure and that I had the departed Cessna 150 in sight.I planned an extended upwind leg to give the Cessna 150 ahead of me enough time to climb; turn crosswind; and then turn downwind. When I saw the Cessna 150 had turned downwind and was abeam me on my upwind leg; I announced that I was turning a left crosswind off of Runway 18. Because of the extended upwind leg; I was slightly above traffic pattern altitude; about 2;500 feet MSL; the traffic pattern altitude is 2;350 feet MSL.While turning left crosswind to left downwind; I saw a low wing airplane out of my left window crossing right to left under me about 200 to 250 feet below which would have placed the low wing airplane very close to; or slightly below; the traffic pattern altitude. It was very hard to estimate the vertical separation because of the closeness and the high relative speeds involved. This placed the low wing airplane on a wide direct entry into the downwind leg for Runway 18. I did not see any traffic on my upwind leg (aside from the Cessna 150) although my pitch attitude was nose up. I did not see any traffic in clearing the area before starting my left turns to crosswind or downwind; but my right wing was high while in these turn. The low wing airplane was coming from my right side. No evasive action was taken; nor was there much time to take any if needed. Because of the close altitude separation; I consider this a near miss incident.I then heard a radio call 'Piper Arrow; does anyone hear this radio?' A blind call answered back 'loud and clear.' I did not hear any calls from a Piper Arrow from engine start to the time of this near miss incident. I suspect that either 1) the Piper Arrow realized too late that he had not been making radio calls; or 2) he made an initial call more than 13 minutes prior and had not made any radio calls while inbound; or 3) the Piper Arrow had radio failure and switched to another radio.I made a radio call to 'Piper Arrow' that he passed under me very close and that I guess he did not see me above. The Piper Arrow made no reply. I then made a second call to 'Piper Arrow' that he was very close to me. Again; no reply from the Piper Arrow until he announced he was turning left base for Runway 18.I was lucky to have made an extended upwind departure and gained a little altitude above the traffic pattern altitude because of the Cessna 150. If I had stopped my climb at traffic pattern altitude; myself and the Piper Arrow would have been very close to a midair collision but I may have had a better chance to see the Piper Arrow if I was in a level attitude. It would have been difficult to spot the Piper Arrow because of the extensive ground clutter making it hard to spot traffic.




Synopsis: GA pilot reported NMAC in the vicinity of non-towered airport.