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59-17-05: Horizontal Tail Spar Fitting

FAA order 59-17-05 is an airworthiness directive. The FAA's subject line: Horizontal Tail Spar Fitting. It names Helio H-391, Helio H-395: about 33 aircraft on the U.S. register today across them, though an order usually covers particular versions or serial numbers rather than every one. System: airframe structure.

What it applies to as the FAA lists it

Kind of product
Aircraft
Makes
Helio Aircraft LLC
Models
H-391B, H-395 (USAF L-28A or U-10B)
On this site
Helio H-391 16 registered
Helio H-395 17 registered

Dates and paperwork

Docket
Unknown
Status
Current
The FAA's document
Read the order on the FAA's site

The order itself the regulatory text, as published

Show the full text (778 characters)
59-17-05 HELIO: Applies to All Model H-391B Aircraft Except Serial Numbers 093, 094, and 098; and Model H-395, Serial Numbers 502 Through 510. Compliance required as indicated. Within the next 10 hours unless already accomplished inspect the horizontal tail front spar splice plate, P/N 391-020-305, for cracks around all bolt holes and the 2.0-inches diameter lightening hole. If cracks are found, the fitting should be replaced with an identically dimensioned part 0.063-inch 4130 steel. If no cracks are found the original aluminum fitting shall be inspected at each 25 hours thereafter until the next 100-hour inspection or October 1, 1959, whichever occurs first, when it must be replaced with a steel part. (Helio Service Bulletin No. 21 covers this subject.)

Related safety bulletins advice on the same designs, not orders

2018-11-21SW-18-31 · NAVIGATION, ATTITUDE, AND DIRECTION DATA SYSTEM
2018-05-09CE-18-14 · Main Landing Gear: Improved inspection at Drag Brace Location
2008-09-09CE-08-47 · Wings - Attachment Fittings

Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of November 6, 2026. Connections as data: /graph/directive/59-17-05.json · aircraft systems.