Service Letter No. 850
Piper PA-39 Twin Comanche C/R · Weight And Balance
Overview
This document is a service letter from Piper Aircraft Company, dated April 18, 1979, addressing the inspection and reinforcement of the aileron nose rib for several aircraft models, including the Piper PA-39 Twin Comanche C/R. It highlights the potential for cracks in the aileron nose rib and provides detailed instructions for inspection and necessary repairs. The letter emphasizes the importance of compliance within a specified timeframe to ensure safety and airworthiness. It includes part numbers for replacement kits and components, along with their suggested prices, and urges pilots and maintenance personnel to act promptly to mitigate risks associated with the identified issue.
- Inspect aileron nose ribs for cracks within the next 100 hours of operation.
- Use a 10x magnifier for visual inspection of the aileron nose bulkheads.
- If cracks are found, order and install the Aileron Nose Rib Reinforcement Kit (Piper Part No. 763 893).
- Logbook entries are required after compliance with the service letter.
- Parts required include Aileron Spar (Piper Part No. 20213-00) and Aileron Reinforcement Plate (Piper Part No. 20234-22).
Document
Source
Originally published by docs.northeastcomanche.org. Sprinkle hosts a reference copy with an added summary, specifications and searchable full text.
Document details
- Type
- Weight And Balance
- Year
- 1979
- Pages
- 3
- File size
- 96 KB
- Publisher
- docs.northeastcomanche.org
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- Pilot's Operating Handbook / AFM
- Checklist
- Maintenance Manual
- Parts Catalog (IPC)
- Systems & Wiring
- Service Bulletins
- Type Certificate (TCDS)
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In this document
Purpose
The purpose of this service letter is to inform owners and operators of the Piper PA-39 Twin Comanche C/R and other affected models about the potential for cracks in the aileron nose rib. It stresses that cracks may develop regardless of previous reinforcement kits installed, necessitating immediate inspection.
Instructions for Inspection
The document outlines a step-by-step procedure for inspecting the aileron nose rib. This includes removing the aileron, visually inspecting the nose bulkheads for cracks using a 10x magnifier, and determining the next steps based on the inspection results.
Material Required
For compliance with the inspection and reinforcement, specific parts are required, including the Aileron Nose Rib Reinforcement Kit (Piper Part No. 763 893), Aileron Spar (Piper Part No. 20213-00), and Aileron Reinforcement Plate (Piper Part No. 20234-22). Suggested prices for these parts are also provided.
Compliance Time
The service letter recommends that the inspection be completed within the next 100 hours of operation or at the next scheduled inspection, whichever comes first. This is crucial for maintaining the aircraft's airworthiness.
Logbook Entry
After completing the inspection and any necessary repairs, a logbook entry must be made to document compliance with the service letter.
Safety notes
- Cracks in the aileron nose rib can compromise aircraft safety and must be addressed promptly.
- Failure to comply with the inspection timeline may lead to safety risks.
Full document text
By SERVICE "~ ,DIPER LETTER Piper Aircraft Co rporCITiOh Lock Haven, Pennsylvania, U.S.A. April 18, 1979 S/M Subject: Aileron Nose Rib Inspection/Reinforcement Models Affected: Serial Numbers Affected: PA-24-180/250 Comanche 24-1 and up. PA-24-260 Comanche 24-4000 and up. PA-24-400 Comanche 26-1 and up. PA-30 Twin Comanche 30-1 and up. PA-39 Twin Comanche C/R 39-1 and up. Compliance Tinie: Recommended within the next one hundred (100) hours of operation or at the next scheduled inspection, whichever occurs first. Purpose: Reports have been received indicating that cracks have developed in the Aileron Nose Rib of several of the above referenced aircraft. It has been determined that the possibility of cracks developing exists in all of the subject aircraft regardless of any previous reinforcement kit installed. This Service Release provides instructions for an initial inspection within the next one hundred (100) hours of operation and for subsequent inspections at intervals of one hundred (100) hours, until such time as a new kit, Aileron Nose Rib Reinforcement Kit, Piper Part No. 763 893, is installed. Instructions: Accomplish on both left and right aileron: 1. Remove aileron from aircraft. With 10x magnifier visually inspect two (2) aileron nose bulkheads for cracks in the area where the aileron balance weight arm attaches. 3. If no cracks are found, reinstall aileron (Rig and lubricate in accordance with appropriate Service Manual.). (over) Service Letter No. 850 Page 2 of 3 Instructions: (continued) 4. If cracks are found in the bulkhead remove the bulkhead, and with 10x magnifier, visually inspect the spar and the aileron reinforcement plate (reference Parts Catalog) for cracks. a. If any cracks are found in an aileron nose bulkhead only, order and reinstall Aileron Nose Rib Reinforcement Kit, Piper Part No. 763 893, before further flight. b. If any cracks are found in the Aileron Spar (Piper Part No. 20213-00) or Aileron Reinforcement Plate (Piper Part No. 20234-22), replace with a like part in addition to Aileron Nose Rib Reinforcement Kit, Piper Part No. 763 893. c. Reinstall Aileron and Balance and lubricate in accordance with appropriate Service Manual. NOTE: If Aileron Spar and Aileron Reinforcement Plates show no evidence of Cracks, and if Aileron Nose Rib Reinforcement Kit, Piper Part No. 763 893 is installed, the one hundred (100) hour recurring inspection recommendation is relieved. 5. Make appropriate Logbook entry of compliance with this Service Release. Material Required: As required per above Instructions: One (1) each per aircraft - Aileron Nose Rib Reinforcement Kit, (Piper Part No. 763 893) at a suggested unit list price of $68.00 C each. One (1) or two (2) each per aircraft, if required - Spar, Aileron (Piper Part No. 20213-00) at a suggested unit list price of $21.58 each. One (1) or two (2) each per aircraft if required: Plate, Aileron Reinforcement (Piper Part No. 20234-22) at a suggested unit list price of $2.33 each. Avai labilitz of Parts: Your Piper Field Service Facility. Service Letter No. 850 Page 3 of 3 Effectivity Date: This Service Release is effective upon receipt. Summarz: Please contact your Piper Field Service Facility to make arrangements for compliance with this Service Release in accordance with ComEIiance Time, above,