Piper PA-31P Pressurized Navajo — Service Bulletins

This Service Bulletin No. 991A, issued by The New Piper Aircraft, Inc., addresses a critical safety issue related to the alternator out light fuse in various Piper aircraft models, including the PA-31P Pressurized Navajo. The bulletin mandates compliance to ensure that the alternator out light switch is adequately protected against potential electrical failures that could lead to smoke entering the cockpit and cabin. The document outlines specific instructions for replacing or modifying the alternator out light fuse, emphasizing the importance of this procedure during the next scheduled inspection or within 100 hours of operation. The bulletin is crucial for maintaining safety and compliance with FAA regulations.

• Compliance with Service Bulletin No. 991A is mandatory for safety.
• The alternator out light fuse must be replaced with part number 461-643.
• Instructions for PA-31P include removing engine cowlings and checking wiring.
• Run-up and functional checks are required after installation.
• Compliance should occur at the next scheduled inspection or within 100 hours.