How KLM’s “Mothballing System” Protects Aircraft from Corrosion
- 19 hours ago
- 3 min read
KLM Cityhopper has developed an advanced “mothballing system” to protect grounded Embraer 195-E2 aircraft during extended periods of inactivity. By sealing aircraft in a controlled environment with regulated humidity and air quality, the system prevents corrosion, preserves components, and ensures rapid return to service when needed.
Published: 15 May 2026
Written by: Shashwat Dwivedi
KLM Cityhopper recently undertook a special project aimed at the maintenance and operational readiness of several Embraer 195-E2 aircraft in its fleet during a long duration of inactivity. The initiative began at Twente Airport, with a focus on ensuring that the aircraft on the ground can be stowed away safely for years without facing any serious degradation or corrosion and remain ready for operations at short notice.
The airline began looking into the preservation techniques when several relatively new Embraer aircraft were taken out of operation due to engine maintenance requirements. With engines removed and sent for servicing, the aircraft themselves faced a prolonged period of inactivity. In a normal scenario, engines would be swapped quickly, and service would resume within a matter of days; however, in cases of extended inactivity due to of engines, this raises the question of long-term storage, which has risks like corrosion, material degradation, and environmental exposure.
To counter the risk of corrosion, the mothballing system was introduced. This involves enclosing each aircraft in a sealed, controlled environment designed to halt the processes that typically lead to deterioration, creating a layer which may be described as a protective cocoon of specialised foil and coating.
A key feature of the system is humidity control. Moisture is a primary contributor to corrosion, mould growth, and the degradation of sensitive components such as rubber and plastics. By maintaining relative humidity at approximately 38%, the system prevents rust formation and inhibits biological growth. Air drying units continuously circulate conditioned air through the sealed enclosure, ensuring consistent conditions without requiring excessive manual intervention.
The system is also equipped to deal with problems like material aging by removing ozone from the air present in the enclosure, reducing long-term wear and tear. The physical setup of the storage system is both modular and comprehensive. Aircraft components such as undercarriages and tyres are carefully prepared and integrated into the sealed environment. For example, undercarriages are placed within airtight aluminium enclosures to prevent moisture transfer from the ground. Even tyres, which are deflated for storage, are included within the protective cocoon to ensure uniform environmental conditions across the entire aircraft.
A sealed entry ensures that the aircraft can be accessed while it is in storage without compromising the whole cocoon. Continuous monitoring systems track temperature and humidity levels, with automated alerts in place to notify operators of any deviations. This ensures that the preservation conditions remain stable throughout the storage period.
From an operational perspective, the project demonstrates the importance of balancing long-term storage with readiness for redeployment. Aircraft preserved using this method can be returned to service within a short timeframe, avoiding the extensive reconditioning that might otherwise be required after traditional storage.
Key Facts
Aircraft are sealed in a controlled “cocoon” environment to prevent corrosion
Humidity maintained at approximately 38% to inhibit rust and mould growth
Ozone removal reduces long-term material degradation
Components such as landing gear and tyres are protected within sealed systems
Continuous monitoring ensures stable storage conditions
Enables faster return to service with minimal reconditioning
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Author: Shashwat Dwivedi Aviation staffing and consultancy insights LinkedIn
