If you own, operate, manage, or fly a Citation 525 series aircraft, it may be time to take a closer look at what is happening beneath the surface—specifically, beneath the lavatory floor.

Brenden Carr, Citation Maintenance Team Lead at West Star Aviation (GJT) reports that maintenance and structures teams have recently identified an increase in aft cabin underfloor corrosion findings across the 525 fleet. “While corrosion is never welcome news, the root cause is often more predictable than you might expect,” said Carr.

The Source: “Mystery Leaks” with Real Consequences

In many cases, this corrosion is not environmental, it is the result of undetected lavatory leaks. What may begin as a minor or intermittent issue can allow moisture and waste fluids to migrate beneath the floor structure, creating a corrosive environment over time.

We have seen a wide range of findings, including:

• Minor corrosion requiring localized treatment
• Moderate structural degradation
• Severe cases involving stringer repairs and engineering involvement

As you might imagine, once structural repairs are required, the scope, downtime, and cost of the maintenance event can increase significantly.

Updated Maintenance Requirement

To address this growing concern, the Citation 525B Maintenance Manual has been updated to include a:

Mandatory 12-month detailed inspection of the aft cabin underfloor structure, specifically the area beneath the lavatory.

The objective is simple—identify and address leaks early, before corrosion progresses into more serious structural damage.

Why Early Detection Matters

Catching corrosion in its early stages offers clear advantages:

• Reduced repair scope and cost
• Shorter downtime
• Less disruption to scheduled operations
• Avoidance of major structural repairs

Simply put, routine inspection is far more efficient than addressing advanced corrosion after it has compromised structural components.

West Star Aviation: Experience You Can Count On

West Star Aviation has extensive experience supporting the Citation 525 series, from routine inspections to complex structural repairs. Our teams are equipped to identify corrosion early, perform necessary repairs, and help operators implement preventive measures to protect their aircraft.

In cases where more advanced structural work is required, West Star’s affiliate DAS Aviation and recent acquisition of Aviation Quality Repair & Design (AQRD) further strengthen our in-house engineering and repair capabilities, allowing us to support even the most complex scenarios with efficiency and expertise.

A Simple Reminder with Big Impact

The takeaway is straightforward:
A quick annual inspection is far less costly than major structural repair.

Staying ahead of potential lavatory leaks and underfloor corrosion helps preserve the integrity of your aircraft—and keeps maintenance events predictable and manageable.