Ensuring Safety and Performance with ASC132 APU Enclosure Modification

Here we showcase our recent project complying with ASC132 Modification of the APU Enclosure. This service bulletin, requiring approximately 350 Labour Hours to complete, outlines crucial steps to enhance the structural integrity and fire safety of the Auxiliary Power Unit (APU) enclosure on applicable Gulfstream G550’s.

Here’s a breakdown of the key modifications performed by our expert team:

Enhanced Enclosure Access: The APU, air/oil cooler ducts, and exhaust duct are carefully removed to ensure thorough access to the enclosure for modifications.

Improved Sealing: Existing sealant in the enclosure corners is completely removed. Titanium machined fittings and fire shields are then installed, providing a strong and fire-resistant barrier.

Reinforced Floor Panels: At the floor access panel openings, existing doublers and nut-plates are replaced with stronger components. Additional fasteners are added to the forward access panel for increased stability.

Advanced Sealant Application: A specified layer of DAPCO 2100 sealant is applied to the enclosure’s internal surfaces, focusing on lap joints, corners, and designated areas of the floor. Formed heat shields are then installed at the fluid drains for additional protection.

Upgraded Enclosure Access Panels: Existing formed-in-place gaskets and quarter-turn fasteners are replaced with a more robust system. Nut-plate retainers, doublers, quick release fasteners, and flame-resistant gaskets are installed for improved functionality and fire safety.

Aft Wall Stiffener Inspection: The enclosure is inspected for the presence of a production-installed aft wall stiffener. If present, any sealant around the installation is completely removed as needed.

Enhanced Exhaust Duct Attachment: The compartment’s attachment flange to the exhaust duct is reinforced with additional fasteners. Any existing sealant is meticulously removed to ensure a secure and reliable connection.

Exterior Bracket Inspection and Cleaning: All exterior brackets of the APU enclosure undergo a rigorous inspection for the presence of fay and fillet sealant. Any brackets found with sealant are removed, thoroughly cleaned, and reinstalled without sealant for optimal performance.

Reinstallation and Testing: Following the modifications, the exhaust duct, APU, and air/oil cooler ducts are carefully reinstalled. The entire system then undergoes rigorous operational and functional checks to ensure everything is functioning flawlessly.

By incorporating ASC132, we guarantee that your Gulfstream aircraft’s APU enclosure meets the latest safety and performance standards. This meticulous process ensures optimal operation and peace of mind for pilots and passengers alike.

At ExecuJet MRO Services, we take pride in our commitment to quality and safety. Contact us today to learn more about our comprehensive maintenance services for your Gulfstream aircraft.