After receiving more than 100 comments and reviewing additional information, the FAA has removed some Cherokee models from AD 2018–CE–049–AD applicability list—but adds three others.
On June 3, 2020, the FAA issued an update to an existing Notice of Proposed Rulemaking (NPRM) on Piper Cherokee PA-28 and PA-32 wing spar cracks.
The update—a Supplemental NPRM (SNPRM)—is an amendment to the original NPRM.
There’s good news In the SNPRM for over 8,000 lower-powered fixed gear PA 28 Cherokee owners and some not-so-good news for Cherokee Six PA-32 260 and PA-32 300 owners.
The FAA removed PA-28-140, -150, -160, -161 and -180 models from the applicability page of the AD; these airplanes are considered “low risk” and are exempt from the proposed AD.
This note in the SNPRM explains why some PA-28 models were removed and why PA-32 models were added
“The FAA developed a more precise methodology for identifying risk. Flight loads of all similar models were compared to those of the PA-28R-201 (accident aircraft) as a baseline. Those aircraft models with calculated wing loads greater than or equal to 95 percent of baseline are considered at-risk and are included in the new effectivity.”
“This risk approach and the resulting change in applicability adds three airplane models (Models PA-32R-300, PA-32RT-300, and PA-32RT-300T).”
The new SNPRM restates the following from the original NPRM:
“This SNPRM would only apply when an airplane has either accumulated 5,000 or more hours TIS [Time in Service]; has had either main wing spar replaced with a serviceable main wing spar (more than zero hours TIS); or has missing and/or incomplete maintenance records.”
And add the following clarification:
“This SNPRM specifies that the owner/operator (pilot) may do the aircraft maintenance records review and the factored service hours calculation. Reviewing maintenance records is not considered a maintenance action and may be done by a pilot holding at least a private pilot certificate. This action must be recorded in the aircraft maintenance records to show compliance with that specific action required by the AD.”
Why is the SNPRM Issued?
Comments on the original NPRM from Piper aircraft, the National Transportation Safety Board (NTSB), and others, along with engineering and load revisions and feedback from inspections caused the FAA to write revisions into the proposal.
The proposed AD will require affected owners to remove two bolts from the outermost end of the wing spar structure attached to the fuselage and conduct an inspection for cracks in that area utilizing a non-destructive method called eddy current inspections.
Eddy Current Inspection Details
The SNPRM cites Piper Service Bulletin 1345 (dated Mar. 27, 2020) and titled, “Main Wing Spar Inspection,” as guidance for carrying out the eddy current inspection.
Other changes from the original NPRM include expanding the qualifications for personnel qualified to conduct the eddy current inspections, increased the estimated labor hours to conduct an inspection, and increased the labor number of labor hours to replace a spar from 32 to 80.
In addition, the SNPRM prevents the installation of a used spar in airplanes with failed spars. Only new spars may be installed.
After each eddy current inspection has been completed, a reporting form in the SNRPM—not the form in SB 1345—must be filled out and sent to the FAA and Piper within 24 hours if cracks are found, or within 10 days if no cracks are found.
The FAA considers this SNRPM an interim action. If data from reports warrant changes, the FAA may take further rulemaking action.
As many readers already know, the original NPRM—issued December 18, 2028— requested that owners and other concerned individuals submit comments regarding the proposed actions in the NPRM. A total of 172 comments were filed before the comment period ended on February 4, 2019.
Piper Flyer readers can access the comments to the original NPRM here. On the right side of the first page this is a window titled, “Enhanced Content.” Click on the “172” comments text to open the file.
This link also provides instructions on how to send comments on the new SNRPM. The new comment period ends July 20, 2020.
Access the revised SNPRM at regulations.gov/document?D=FAA-2018-1046-0180
My article on the original NPRM “Piper PA-28 and PA-32 Wing Spar NPRM 2018-CE-049-AD” can be accessed here: https://tinyurl.com/EllsCherokeeWingSpar1
That article includes information on 100-hour inspections and how to calculate factored service hours.
Steve Ells has been an A&P/IA for 45 years. He is a commercial pilot with instrument and multi-engine ratings and loves utility and bush-style airplanes and operations. Ells an associate editor for AOPA Pilot. He owns Ells Aviation (EllsAviation.com) and lives in Templeton, California. Send questions and comments to editor [AT] cessnaflyer [DOT] org.
Newly issue SNPRM: regulations.gov/document?D=FAA-2018-1046-0180
Original NPRM: tinyurl.com/NPRMCherokeeWingSpar122118