Narrative:

Departed runway xxr for a right downwind VFR ZZZ departure. I was told to do ZZZ departure; 1600 VFR and contact approach. Upon contacting approach [co-pilot]; I leveled off at 1600 feet then started the cruise checklist. Turned left fuel pump off; then once the right fuel pump was turned off we felt right yaw. When I put the fuel pump back on for the right engine; there was no change in fuel flow or RPM. Then I verified with right throttle back; no change in performance or RPM in right engine. I decided to secure the engine and did the feathering procedures; I asked [co-pilot] to verify with the emergency checklist and returned back for a landing. As I was securing the engine; [co-pilot] told approach that there was a loss of power in the right engine and want to turn back to ZZZ for a landing. Approach asked if [we wanted to request priority handling]; [co-pilot] asked me to verify if I wanted to [request priority handling]; and I said yes. [Co-pilot requested priority handling] with approach; and squawked 7700. Approached told us to turn right back to the airport; and contact ZZZ tower. Switched to tower frequency; and again [co-pilot] said 'mayday mayday mayday;' and tower said cleared to land runway xxr. Landed safely and smoothly. Taxied back to parking and tied down aircraft.

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Original NASA ASRS Text

Title: Piper PA-34 Seneca pilot reported a loss of power on the right engine due to a suspected fuel system anomaly.

Narrative: Departed Runway XXR for a right downwind VFR ZZZ departure. I was told to do ZZZ departure; 1600 VFR and contact approach. Upon contacting approach [Co-Pilot]; I leveled off at 1600 feet then started the Cruise Checklist. Turned left fuel pump off; then once the right fuel pump was turned off we felt right yaw. When I put the fuel pump back on for the right engine; there was no change in fuel flow or RPM. Then I verified with right throttle back; no change in performance or RPM in right engine. I decided to secure the engine and did the feathering procedures; I asked [Co-Pilot] to verify with the emergency checklist and returned back for a landing. As I was securing the engine; [Co-Pilot] told Approach that there was a loss of power in the right engine and want to turn back to ZZZ for a landing. Approach asked if [we wanted to request priority handling]; [Co-Pilot] asked me to verify if I wanted to [Request Priority Handling]; and I said yes. [Co-Pilot Requested Priority Handling] with Approach; and squawked 7700. Approached told us to turn right back to the airport; and contact ZZZ Tower. Switched to Tower frequency; and again [Co-Pilot] said 'Mayday Mayday Mayday;' and Tower said cleared to land Runway XXR. Landed safely and smoothly. Taxied back to parking and tied down aircraft.

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.