AD 2021-11-16 Required Repetitive Inspections Of The Spar Carry Through Assembly

The FAA is superseding Airworthiness Directive (AD) 79-01-03, which applied to certain Piper Aircraft, Inc. (Piper) Model PA-36-285 airplanes, and AD 83-20-03, which applied to Piper Models PA-36-285, PA-36-300, and PA-36-375 airplanes.

AD 79-01-03 required repetitive inspections of the spar carry through assembly until replaced with a different part numbered spar carry through assembly. AD 83-20-03 established life limits for the wing spar structural components. This AD retains the requirements in AD 79-01-03 and AD 83-20-03 and requires the spar carry through assembly inspection from AD 79-01-03 for additional airplanes and adds life limits for certain wing structural components previously omitted from AD 83-20-03 for certain serial numbered airplanes. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective July 15, 2021.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 79-01-03, Amendment 39-3383 (44 FR 36, January 2, 1979), Docket No. 78-EA-69 (AD 79-01-03) and AD 83-20-03, Amendment 39-4739 (48 FR 45535, October 6, 1983), Docket No. 83-CE-23-AD (AD 83-20-03). AD 79-01-03 applied to certain Piper Model PA-36-285 airplanes and required repetitive inspections of spar carry through assembly part number (P/N) 97370-00, with repair as necessary, until the spar carry through assembly is replaced with P/N 76824-02. AD 83-20-03 applied to Piper Models PA-36-285, PA-36-300, and PA-36-375 airplanes and established life limits for certain wing structural components.

The NPRM published in the Federal Register on March 23, 2021 (86 FR 15439). The NPRM was prompted by inconsistencies between the two ADs and the airplanes' type certificate. The FAA determined that the life limits for the spar carry  through assembly, P/N 97370-00 or 76824-02, were inadvertently omitted from AD 83-20-03 for certain airplanes. In the NPRM, the FAA proposed to add the life limit for the spar carry through assembly for Models PA-36-285 and PA-36-300 airplanes, serial numbers 36-7660123 through 36-8160023; and Model PA-36-375 airplanes, serial numbers 36-7802001 through 36-8302025. The FAA also determined the repetitive inspections of the spar carry through assembly required by AD 79-01-03 should apply to both Model PA-36-285 and Model PA-36-300 airplanes until the life limit replacement of the spar carry through assembly with P/N 76824-02. In the NPRM, the FAA also proposed to require adding the repetitive inspections for the Model PA-36-300 airplanes. After the initial life limit replacement of the wing spar carry through assembly, P/N 97370-00 with P/N 76824-02, the repetitive inspections will no longer be required. The FAA is issuing this AD to address the unsafe condition on these products.

FMI: www.regulations.gov