AD 57-25-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Helio Aircraft LLC | H-391B | Airworthiness Directives; Helio Model H-391B Aircraft |
Unsafe Condition
Cracks have been found in the fin front spar underneath the steel attachment fittings holding the stabilizer to the fin. Cracks were also discovered in the flanges of the fins nose ribs second and third from the bottom.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect visually for cracks in the fin front spar and lower nose ribs within specified intervals. Stop-drill and reinforce parts if cracks are found. Reinforcement must be done prior to 400 hours total time or within 25 hours flight time for aircraft with 400+ hours, as per Helio Service Bulletin No. 17.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Compliance required as indicated.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Helio Model H-391B Aircraft Serial Numbers 001 Through 055.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.