SERVICE BULLETIN NO. 1379A

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(OVER) Date: July 27, 2023 (S) SER V ICE BUL L E TIN NO. 1379A PIPER CONSIDERS COMPLIANCE MANDATORY ATA/JASC: 5540 Piper Aircraft, Inc. 2926 Piper Drive Vero Beach, FL, U.S.A. 32960 Service Bulletin (SB) 1379A supersedes SB 1379 in its entirety. Aircraft that were previously made compliant with SB 1379 are in compliance with SB 1379A. SUBJECT: RUDDER INSPECTION REASON FOR REVISION: To revise models affected, serial numbers affected, approval statement, and revise instructions and figure artwork to improve the clarity of the service bulletin. MODELS AFFECTED: SERIAL NUMBERS AFFECTED: J-2 Cub ALL J-3/L-4/NE-1/NE-2 Cub ALL J-4 Cub Coupe 4-400 thru 4-1649 PA-11/L-18B Cub Special 11-1 thru 11-1353 PA-15 Vagabond 15-1 thru 15-388 PA-16 Clipper 16-01, 16-2 thru 16-736 PA-17 Vagabond 17-1 thru 17-215 PA-18/-18A/-19/L-18C/L-21A/L-21B Super Cub 18-1 thru 18-9004 18-7309016 thru 18-7409151 18-7509001 thru 18-8309025 1809002 thru 1809113 19-1 thru 19-3 PA-20 Pacer 20-01, 20-1 thru 20-1121 PA-22 Tri-Pacer 22-1 thru 22-532 COMPLIANCE TIME: To coincide with the next regularly scheduled maintenance event, but not to exceed the next 100 hours time in service. APPROVAL: The engineering aspects of this service document have been shown to comply with the applicable Federal Aviation Regulations and are FAA approved. PURPOSE: Rudders installed on the affected aircraft may have a rudder post manufactured from American Iron and Steel Institute (AISI) 1025 carbon steel. Over time, rudder posts manufactured from 1025 steel are prone to fatigue failure, which could lead to loss of control of the aircraft. If it cannot be confirmed that the rudder post is made of 4130N steel, this service bulletin mandates the replacement of the rudder with one that is known to contain a rudder post made from 4130N steel. SERVICE BULLETIN NO. 1379A PAGE 2 of 5 INSTRUCTIONS: NOTE: Instructions contained within this service bulletin apply only to genuine Piper parts. Piper has no knowledge of the materials or manufacturing processes used by STC (Supplemental Type Certificate) or PMA (Parts Manufacturer Approval) holders that manufacture replacement parts for Piper products. Contact the component manufacturer for guidance. NOTE: Replacement parts for affected aircraft may no longer be available from Piper. NOTE: Early Piper Aircraft models were certified under CAR 3 rules and there is no regulatory requirement for a manufacture’s maintenance manual. For aircraft models that do not have an Airplane Maintenance Manual (AMM) or Service Manual (SM), Piper recommends the use of AC 43-13-1B (or latest revision). See also “Civil Aeronautics Manual 18”. The affected aircraft will fall into one of the following categories: • For aircraft with an airworthiness certificate issued prior to June 3rd, 1974, these aircraft were delivered from the factory with a rudder post made from 1025 steel. If a complete service history exists and it can be confirmed that the original rudder is still installed, proceed to Part II. Otherwise, proceed to Part I. • For aircraft with an airworthiness certificate issued on or after June 3rd, 1974, these aircraft were delivered from the factory equipped with a rudder post made from either 1025 steel or 4130N steel. At owner/operator discretion, proceed to Part I. Otherwise, proceed to Part II. • Aircraft equipped with a rudder of unknown or incomplete service history may have a rudder post made from either 1025 steel or 4130N steel. For these aircraft, the type of steel alloy used in the manufacture of the rudder post cannot be determined by visual inspection. At owner/operator discretion, proceed to Part I. Otherwise, proceed to Part II. Part I. Inspection Instructions in Part I are at owner/operator discretion. If Part I is not accomplished, proceed to Part II. NOTE: As an alternative to the acid test method described in this service bulletin, a portable X-ray Fluorescence (XRF) analyzer may be used to determine the alloy used in the rudder post. Follow device manufacturer’s instructions. 1. Remove the rudder from the aircraft and place on a flat horizontal work surface. 2. Mark the location along the rudder post according to Figure 1. Remove fabric covering to reveal a 3–5 inch length of rudder post tube. Using 220-grit or finer abrasive paper, remove paint, primer and any visible corrosion, to achieve a bare metal surface free of contamination. 3. Solvent wipe area with isopropyl alcohol or acetone to remove any debris. Allow solvent to evaporate. 4. Obtain a small quantity of Certified ACS nitric acid (70% v/v). One possible source is Fisher Scientific under Catalog No. A200-500. NOTE: Thoroughly review the nitric acid Safety Data Sheet (SDS) that is supplied by the chemical manufacturer. Don all required personal protective equipment (PPE) and ensure all exposure controls are in place prior to performing the nitric acid test below. SERVICE BULLETIN NO. 1379A PAGE 3 of 5 WARNING: NITRIC ACID IS HIGHLY CORROSIVE AND TOXIC. IT CAN CAUSE SERIOUS EYE AND/ OR SKIN DAMAGE. IN CASE OF ACCIDENTAL RELEASE, DO NOT BREATHE VAPORS OR AEROSOLS. AVOID SUBSTANCE CONTACT. CAUTION: BEFORE CONDUCTING THE TEST, PREPARE A BAKING SODA PASTE TO NEUTRALIZE THE ACID AND ENSURE WATER IS AVAILABLE TO CLEAN THE RUDDER POST. 5. Apply one drop of the 70% nitric acid onto the surface of the part. Do not allow nitric acid to drip/run. Observe the drop for a reaction, which, if it occurs, will be immediate. • If the drop remains clear, the rudder post is made from 4130N steel. No replacement interval applies. Proceed to step 6. • If the drop turns a yellowish orange or brown, the rudder post is made from 1025 steel. In this configuration, the rudder is subject to a replacement interval. Proceed to Part II. NOTE: Regardless of findings, neutralize the drop of acid using a baking soda paste, followed by a clean water rinse and drying. Any unused waste nitric acid must be disposed of in accordance with the