The U.S. aviation regulator FAA has issued a supplemental notice of proposed rulemaking (SNPRM) that addresses feedback from concerned parties about their proposed Airworthiness Directive (AD) calling for the installation of inspection panels on the lower side of the inboard wing section of certain PA-28-140s, 28-150s, 28-160s, 28-180s, 28-235s, 32-260s and 32-300s.

The inspection panels would allow for visual access to the wing spar area that is otherwise difficult to access. If corrosion were to be found, the AD required corrective action to be taken. The original NPRM was issued on November 7, 2017 and was prompted by a number of reports of ‘significant corrosion’ at the wing spar.

Responding to feedback received from a few individuals and the AOPA (which the FAA misidentifies in the SNPRM as the Airline Owners and Pilots Association), the FAA released more details on what provoked the proposed AD. The regulator cited two PA-28-161s, one in Chile and one in Scotland, where significant corrosion had been found during or after the installation of wing inspection panels. The AOPA also requested the FAA publish its Small Airplane Risk Assessment (SARA) on the issue.

A key concession that the FAA has made in the SNPRM was to drop the requirement for the installation of inspection panels and allow for borescope inspections.

Appended below is a PDF version of the SNPRM. Those wishing to contribute a comment to the FAA on this SNPRM can do so by clicking here.

Photo credit: Scott Kinney