Flight Crew Private; Flight Crew Instrument
Flight Crew Last 90 Days 30; Flight Crew Total 4100; Flight Crew Type 3500
Communication Breakdown; Workload; Time Pressure; Situational Awareness
Aircraft Equipment Problem Critical; Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Fuel Issue
Flight Crew Diverted; Flight Crew Landed in Emergency Condition; Flight Crew Landed As Precaution
Aircraft; Human Factors
I had seen tach fluctuation on a previous flight from ZZZ1 to ZZZ 2 days prior. Since I was in [city] on business I decided to take the airplane up for a short checkout flight to assess the tach issue. I checked the FAA TFR site for TFR restrictions and did not see any listed. I pre-flighted the airplane per my usual checklist; including visual fuel inspection and oil level. I took off VFR from ZZZ and headed north to avoid the town while I checked the airplane inflight at an altitude of 2;000'. Approximately 10 minutes after [takeoff] my engine began surging wildly; and the tach followed. I was fearful of a catastrophic engine failure even though oil pressure and temp were normal. This persisted for approximately 1 minute consistently; even after switching tanks and applying the fuel pump. I decided to get the airplane on the ground immediately and hit my 'NRST' button on my GPS and it responded that ZZZ2 was within range. I proceeded directly to ZZZ2 and saw the TFR inner ring on my GPS display; so I was fully aware that I would intrude on the TFR; but this was an emergency and I decided to proceed. I was intercepted by a Coast Guard helicopter and I tried to communicate with him on the ZZZ2 radio frequency but we did not hear each other. I landed at ZZZ2; taxied up to the ramp and shut down. I was met by Secret Service and Coast Guard officials. I went into the FBO and contacted TRACON and told them it was an emergency landing. As it turned out; I was taking off into a TFR (outer ring) from ZZZ even though the FAA TFR site did not list it. That was completely unintentional but my error was in NOT calling FSS for a TFR report/briefing. The mechanic at ZZZ2 proposed that I had water in my gas tank which made sense because I believe the airplane was refueled in a hard rain; so it is possible that when I pulled gas from the sumps and inspected them during my preflight; I may have seen pure water and not the light blue of AvGas. I think water was the cause of the engine problem and the mechanic at ZZZ2 corroborated that. He did a full run up and saw the tach fluctuation but said it was not serious and saw no other irregularities in the engine performance. It is likely that the water in the tanks went through completely by the time I landed the airplane.
PA32 pilot reported violating a TFR while handling an inflight engine roughness emergency likely caused by contaminated fuel.