Splendid Aviation Inc.

Recently, one of my flight instructors and our general manager tested a Piper Cherokee 140 following maintenance on the oil system. We were having issues with the Oil Temperature. I'll explain that Journey on another blog. Anyway, during the test, everything seemed normal, including the run-ups. Since operations were normal, my team proceeded to take off. Following clearance for takeoff, they lined up on the runway, added power, and immediately were shocked because the aircraft began unusually vibrating—the whole airframe. The takeoff was aborted, and they returned to the Flightline. This was shocking because I flew the plane the day before without issues. 

This situation was very frustrating. We spent two weeks troubleshooting the oil system, and now, another issue exists. So we began talking it through. Everything from the fuel pump to bad cylinders was mentioned, so I decided to take my Flight Instructor and Replicate the issue. Once again, start-up and run-ups were fine. However, when at full power, the aircraft excessively vibrated. To troubleshoot, I first isolated the Magnetos, which were adequately functioning; then I tried the Carb Heat, which was fine, and then I tried reducing the mixture. Whala, that worked. The engine purred like a kitten with the mixture halfway to the cutoff. 

**FUEL ISSUE**



Following that experiment, we determined a fuel issue. But I couldn't understand what triggered it. We installed a new Carburetor three months ago, and it only had about 200 hours on it. Therefore, my team began troubleshooting the induction System, Fuel Pump, Air intake, and Filter, then re-adjusted the Carburetor settings. As we began re-adjusting it, I wondered why it needed re-adjustment. Was there an underlying problem? Lastly, we adjusted the mixture setting to the stop and couldn't adjust any more. The team subsequently began troubleshooting again. Mixture unit, throttle unit, air intakes again, induction system again. At this point, I began to suspect a faulty Carburetor and purchased one before the weekend from Aircraft Spruce. 

The Carburetor was delivered the next day and installed into the aircraft. That fixed the problem. 

What is the moral of the story? Sometimes, parts go bad earlier than advertised. I over-summarized the situation because, during the brainstorming sessions, the manufacturer convinced my team that there was no way the Carburetor went bad. However, the A&P IA at the airport stated that new parts go bad. It sucks, but that happens. If you ruled out all other possibilities, call a spade a spade and take action.

I'll explain our fix to the oil system in the next Blog. Happy Flying.