PA-31 Navajo/Chieftan/Mojave/T1040
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 100; Flight Crew Total 5100; Flight Crew Type 1900
Communication Breakdown; Situational Awareness; Distraction
Conflict NMAC
Procedure; Airport; Aircraft
Began position reporting 10 miles north of ZZZ and reported position at 5 miles and 1 mile from the airport. Upon hearing a slower aircraft on left crosswind I widened my pattern and slowed to stay outside this aircraft until I had it in sight. During this time another aircraft departed that I did not see or hear on the CTAF. Paths crossed with 300 feet separation. I didn't see this aircraft until someone on the frequency mentioned their position. It bothered me that despite vigilance and planning to avoid known traffic flows we came this close. Maneuvering space at this airport is compressed by its proximity to another airport and Class C airspace. Ironically; this aircraft was being flown to this airport for avionics that would include traffic reporting capabilities.
A pilot flying into a non towered airport reported a NMAC with a departing aircraft.