Turboprops play a major role in Southeast Asia’s regional aviation, but storing them in the high-humidity climate comes with unique challenges.

Southeast Asia is one of the world’s largest turboprop markets, with Indonesia alone home to one of the biggest ATR operators. Humidity in many parts of the region frequently exceeds 70–80%, introducing preservation considerations that differ from drier operating environments. 

Notably, the high humidity creates the ideal breeding ground for potential fungus and drastically increases the risks of corrosion, leading to a higher need for attention to detail and understanding of technical risks for airlines operating in the region.

Preservation of ATR Aircraft -- The Basics

Unlike jet aircraft, turboprops such as ATR42 and 72s do not rely on an APU. Instead, beside the engine, like its jet counterparts, the propeller system becomes a key preservation focus. The propeller has its own lubrication system integrated with the turbomachinery.

As we covered in our previous post, preservation requirements vary depending on storage duration. For short-term parking or after propeller reinstallation prior to return to service or lessor delivery, weekly propeller rotation is required to maintain lubricant distribution. For longer-term storage, propellers may remain installed or removed and preserved under controlled packaging and environmental conditions, sometimes allowing inspection intervals of up to one year.

Southeast Asia’s also means increased fungal and corrosion risk, which could worsen if preservation procedures are not properly implemented.

Of course, certain areas are more subject of the elements than other, with exposure being one of the factors. Common areas requiring attention include: 

• aileron tab control mechanisms

• elevator & flight control linkages

• upper wing panels (overwing areas

• gravity refueling caps

• static port anchor nut

Common Gaps to Note during Aircraft Transition

Lack of attention to these areas can lead to corrosion, which may compromise the aircraft’s structural integrity. As such, maintenance personnel's competency must be ensured to support the consistent execution of required tasks, with sufficient awareness to identify potential pitfalls.

From field experience, the most common gaps are observed in:

• Incomplete lubrication

• Improper installation of protective covers

• Skipped desiccant replacement

• Delayed treatment of corrosion

• Inadequate control of outdoor humidity conditions

Aside from corrosion and technical findings, records traceability remains a key concern for lessors and asset management firms. They must ensure that no mandatory tasks are missed and that all activities remain aligned with the maintenance schedule. This includes verified AD compliance with complete supporting documentation, continuous LLP tracking, and proper documentation for any preserved, robbed, removed, or replaced parts, ensuring no configuration deviations occur without approval.

These conditions become particularly relevant during long storage periods, but are also important considerations during mid-lease inspections and aircraft redelivery.

About TBM Aviation

TBM Aviation TBM Aviation is the go-to provider in Southeast Asia for reliable technical support to support you with your fleet, including physical inspections, pre-purchase inspection, asset transition management, and record audits.

We combine hands-on expertise with a cost-conscious approach to help lessors, airlines, and asset managers maintain compliance and protect asset value throughout the aircraft lifecycle. Insights from our reports have helped clients identify safety and financial risks. With our experience serving both lessors and lessees, we understand that even the smallest defects can have a significant impact and know how to flag details often overlooked.

To consult your technical challenges, reach out to our team at info@tbmaviation.com