PA-31 Navajo/Chieftan/Mojave/T1040
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical
Flight Crew Returned To Gate; General Maintenance Action; General Flight Cancelled / Delayed
Aircraft
After unloading freight; started engines on ramp for second leg. Because flight director/autopilot circuit breaker had tripped on the way in (after I had already reset it during originating flow); I called local maintenance and spoke with a mechanic. We MEL'd the flight director/autopilot per standard procedures. While doing this; the engines were running for about 15 minutes at 1;000 RPM and lean mixture setting. Engine gauges were normal.After getting the latest ATIS; I called ground control for my clearance and taxi instructions. Taxi to Runway was normal. After being cleared for takeoff; I taxied into position and checked runway heading against directional indicators. The procedure for setting takeoff power I have been taught to use at high density airports such as this is: (1) 1;500 RPM; (2) mixtures full rich; (3) 2;000 RPM; (4) emergency fuel pumps 'ON'; (5) 30 inches manifold pressure; (6) full power after turbochargers have spooled up. As I advanced the throttles for takeoff; the left engine power settings came up as expected but the RPM from the right engine wouldn't go over 1;300 RPM even though the manifold pressure came up. There was a serious split in the power settings between the two engines. Obviously something was wrong. I called tower and said I needed to taxi back to the ramp to do a run up; which I did. Again; I couldn't get the right engine to develop any power above 1;300 [to] 1;400 RPM even though the manifold pressure came up. It seemed like the right engine was loading up bogging down. After a few seconds the engine would quit. I did perform a mag check and the mags seemed fine. I also heard some sporadic popping sounds from the right engine -- they were not full-blown backfires; just popping sounds. So I called local maintenance and first spoke with a mechanic; who told me to call Maintenance Control. HE told me to write up the squawk in the Aircraft Maintenance Log (AML); which I did. He said that we have been having some problems with the fuel controllers for the Chieftains over the past six months or so. While he was on the phone; I started the right engine about three or four times and we tried various combinations of throttle and mixture settings. He was concerned about fuel pressure and pump settings. While I was able to get a little more RPM from the right engine; it was still not developing anywhere close to full power and I couldn't keep the right engine running after advancing the power for more than twenty or thirty seconds or so each time.At that point; I shut the airplane down and secured it on the ramp. They sent the reserve pilot to pick up the freight and me and fly us back.
A PA31 pilot reported abnormal engine indications while attempting to set takeoff power. Numerous run ups and checks fail to achieve normal power and the aircraft is grounded. Maintenance Control indicated that they have been having trouble with fuel controllers for the past six months.