Spirit Wing Aviation of Guthrie, Okla., planned to have its Williams FJ44-powered Learjet 25D prototype back in the air by the end of last month, following its grounding after about eight hours of flight testing that started with its January 9 first flight. “The flight testing showed some things to improve, including cabin pressurization,” Mike Penwell, Spirit Wing v-p of operations, told AIN, “but the main thing that held us up was the need to obtain a new data acquisition system. We had leased an acquisition system for the initial baseline flights from Flight Testing Associates of Mojave, Calif. [which also employed the test pilots], but when we went back to them for the later flights with the modified airplane, the system was not available. So we contracted with FTA to build a system specifically for us.” Despite the delay, Penwell said he still expects Spirit Wing will receive the STC for the engine modification by late fall.
Calvin Burgess, owner and president of Spirit Wing, said despite having lists of interested customers, he still refuses to begin taking deposits. “Although we’ve done the mod on one airplane, we really don’t know how long the process will take, so we can’t realistically determine the installation cost. We’ll have a better idea after we do the second airplane, and we’ve already begun stripping its paint. We’ve also received one of its engines from Williams, out of 24 ordered, and the next one is due in July.”
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