Superior Pulls Engines From Service

When we first learned of the breadth of the detonation problem, we contacted XP-400 engine owners and paid to have them ship their engines to our facility for evaluation, Superiors Bill Ross told sister publication Kitplanes. We disassembled, inspected and tested the key components in each engine, he said, but even after adjusting the ignition timing specification, the results were still unsatisfactory. In response, the company decided to ground affected engines and create a buyback program.

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Sunday, April 28, 2019 at 12:00 AM ET

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Key Takeaways:

Superior Air Parts grounded approximately 120 experimental aircraft using its XP-382 and XP-400 engines due to persistent, unresolved detonation problems and implemented a buyback program for these affected engines.
Despite inspections and timing adjustments, Superior Air Parts could not define a consistent root cause for the detonation issues, leading to the decision to remove all XP-382 and XP-400 engines from service, impacting owners who now need alternative powerplants.
The FAA issued a maintenance alert for Cirrus SR20/22 aircraft, recommending visual verification of the left aileron actuation arm and attach bolt's safety wire during preflight after an accident, with Cirrus updating its manuals to emphasize this inspection.

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Superior Air Parts announced in March it was implementing a program with the effect of grounding some 120 experimental aircraft powered by its XP-382 (200 hp) and XP-400 (215 hp) engines. The manufacturer of both FAA-certified and experimental engine parts in January published a service bulletin calling for a change in the XP-400’s ignition timing, from 25 degrees BTDC to 20, with the intent of preventing detonation-induced damage operators were experiencing.

The service bulletin noted, “Engines that have accumulated any flight time must have the engine disassembled and, using non-destructive testing methods, the crankshaft inspected for the presence of fatigue cracking or piston and connecting rod damage caused by incipient, moderate, or severe detonation. The engines must be removed and sent to Superior Air Parts or its authorized representative for disassembly and inspection.”