I had trained for my complex and high-performance endorsements in an airplane that was certified with an engine that does not meet high-performance criteria but had been modified by STC such that it did meet criteria.
The logbook endorsement mentions the model of the airplane and that it had been modified such that the aircraft produced more than 200 horsepower. The question is do I need to actually track down the STC information just in case of a ramp check or when going for a more advanced pilot certificate?
This question was posted due to a conversation with a flight instructor who had balked at the legality of the endorsement. His argument essentially went like this:
1) If you have an aircraft with a "200 HP" factory new engine, you put it on a dyno, it generates 205 HP. It's still a "200 HP" engine as per the FAA.
2) If you have an aircraft with a "200 HP" engine, you do a top-of-the-line overhaul, you put it on a dyno, it generates 205 HP. It's still a "200 HP" engine as per the FAA.
3) If you have an aircraft with a "200 HP" engine, you apply an STC that changes the cylinder and piston configuration to intentionally generate 205 HP, you put it on a dyno and it does make 205 HP, now because the intent of the STC being to generate more than 200 HP and the FAA approval via STC as a "more than 200 HP" engine the aircraft only at this point meets the high-performance criteria.
His argument was that in cases 1 and 2, since the engine was not "modified" with the specific intent to generate more than 200 HP you merely won the horsepower lottery but it's still certified as a 200 HP engine. He had questioned whether the STC was intended to bring the power output above 200 HP or if it was just an accidental byproduct and it was still therefore certified as a 200 HP engine.