Superior Grounds XP-382 And XP-400 Engines


Image: Kitplanes – Superior XP-400 crankshaft

Superior Air Parts has grounded all of its XP-382 and XP-400 experimental engines due to detonation problems found in some XP-400s, according to AVweb sister publication Kitplanes. The company has also implemented a mandatory buy-back program for both engine types. Both the grounding and the buy-backs are effective immediately.

“Throughout Superior Air Parts’ 50-plus year history, we have stood behind the quality and safety of our products,” said Superior VP of Sales and Marketing Scott Hayes. “While the financial burden of this buy-back is significant, it is not as stressful as thinking that we have failed, in any way, to do what we could to protect the safety of our customers and their passengers.”

Superior says that extensive testing and evaluation could not determine a consistent cause for the detonation problems and attempts to adjust the engine’s ignition timing did not yield results the company found satisfactory. The issue was only observed in XP-400s but due to the number of internal components shared by the XP-382, the decision was made to remove it from service as well. The company also noted that the majority of XP-400s tested showed “no signs of stress wear or damage.”

Superior has already begun to contact XP-382 and XP-400 engine owners to arrange the buy-backs. The issue does not affect Superior XP-320 or XP-360 engines.