Date: 201510
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Taxi
ATC / advisory: CTAF ZZZ
Second aircraft: Skyhawk 172/Cutlass 172
Aircraft component: Air/Ground Communication
Component problem: Malfunctioning
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Instrument; Flight Crew Private
Human factors: Communication Breakdown; Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe; Conflict Ground Conflict; Critical
Detector: Person Flight Crew; Person Passenger
When detected: Taxi
Result: Flight Crew Took Evasive Action
Contributing factors: Human Factors; Aircraft; Procedure
Primary problem: Ambiguous

Narrative: I taxied from the ramp to the runway. Along the fairly long taxi route; I monitored the CTAF and took the opportunity to observe any traffic in the pattern and generally get a good picture of activity around the airport. Upon approaching the hold short line for the runway; I stopped; performed my run up and systems checks; and then again looked for traffic on downwind; base and final legs in the pattern. Observing no traffic; I made a transmission on the CTAF that I was taking [the runway] for departure; and proceeded past the hold short line while continuing to look for traffic in the pattern and airport surface. As I approached the edge of the active runway; my pilot rated passenger observed an aircraft on an approximately 1 mile final. I immediately stopped our aircraft; then turned around and exited back across the hold short line; and turned around to be able to observe the runway.The traffic we had observed on final continued its approach and landed without any apparent change in its approach path. I am unsure if the pilot of the other aircraft had observed our movements on the ground. After touch down we heard a couple of silent carrier transmissions on the CTAF; and I transmitted to the aircraft that just landed that there was no audio on their transmissions. After a short time; the pilot of the aircraft transmitted that they had experienced a radio problem; and thanked me for the report.After making a very thorough check for other traffic; we departed without further incident.I had an extensive discussion with my passenger about how both of us had initially missed seeing the traffic on final. Based upon the facts; it was apparent that my scan for traffic was ineffective in picking up the other aircraft. This was likely due to the angle of my aircraft relative to the final approach portion of the pattern; where parts of my aircraft structure may have blocked my view. Had I moved the aircraft as I usually do in order to get a wider view of the airspace; I would have had a better chance of seeing the traffic that I had missed.Contributing factors were:1) The lack of hearing position reports from the aircraft that was experiencing radio troubles2) Over reliance on my part that a quiet CTAF signified no traffic3) Obscuration of vision toward final due to aircraft orientation; coupled with the 45 degree angle the taxiway joins the runway4) No landing light observed on approaching aircraftCorrective actions:1) Never assume that a quiet CTAF means anything other than an unknown traffic condition. Some aircraft may not have radios or are experiencing a malfunction2) Always assure an unobstructed view of all portions of the pattern by adjusting the orientation or circling the aircraft as needed




Synopsis: After making appropriate CTAF radio announcements and entering the runway environment; a Piper pilot and passenger observed landing traffic on short final; so they quickly exited the runway. It was later determined that the landing aircraft had experienced radio problems.