The 225-hour commercial pilot, 55, had built his JD-2 Dyke Delta in St. Louis and, after several test flights there, took it to Safford, Arizona. Originally intended as a roadable aircraft, the JD-2 had folding wings and sufficiently springy main gear and large tires to allow it to be towed behind a car. It made the 1,400-mile trip without incident.
Sometimes It’s Better Just to Follow the Instructions
Key Takeaways:
- A pilot fatally crashed his homebuilt JD-2 Dyke Delta on its first flight after significant modifications, with the NTSB citing his inability to recover from a stall/mush condition due to improper planning/decision.
- The pilot made unauthorized alterations to the experimental aircraft, including installing a heavier engine, adding lead ballast, and incorporating unapproved trailing edge tabs and a T-tail, in an attempt to correct persistent nose-heaviness and an unusually high reported stall speed.
- These modifications likely exacerbated the Dyke Delta's inherent sensitivity to center of gravity and compromised its longitudinal stability and stall characteristics, especially in a tailless design already prone to a high sink rate during a stall.
- The incident highlights the critical importance of adhering to proven designs and avoiding unapproved, aerodynamically unsound modifications in experimental aircraft, even for experienced builders.
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