59-21-02: Wing Leading Edge Screws
FAA order 59-21-02 is an airworthiness directive. The FAA's subject line: Wing Leading Edge Screws. System: airframe structure.
What it applies to as the FAA lists it
- Kind of product
- Aircraft
- Makes
- Lockheed Martin Corporation
- Models
- 188A, 188C
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 (1,018 characters)
59-21-02 LOCKHEED: Applies to All Model 188 Series Aircraft.
Compliance required as indicated.
Due to repeated loosening of wing leading edge attachment screws between the fuselage and the outboard nacelles, the following inspections shall be conducted:
(a) At each 50 hours of service time, visually inspect the leading edge attachment screws, top and bottom, from the fuselage to the outboard nacelles, paying particular attention to screws adjacent to nacelles. Tighten any screws found loose.
(b) At 300-hour intervals retighten all affected screws to 25 to 40 inch-pounds torque.
The above inspection program may be discontinued upon the removal of the NAS 517-3 screws from all leading edge attachments, top and bottom, and the installation of LPHT 517-3 screws. Torque all new leading edge attaching screws to 45-55 inch-pounds.
(Lockheed Service Bulletin 88/SB-334 covers this same subject.)
NOTE: LPHT-517 refers to Lockheed Specification for a Long-Lok, Polyvinyl insert, High torque screw.
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/59-21-02.json · aircraft systems.