PUREair - The Ultimate in Helicopter Engine Protection


The Ultimate in Helicopter Engine Protection

If airborne contamination is ingested by a helicopter engine, it can cause severe damage, e.g., erosion, corrosion, and component wear. Helicopters have to be ready 24/7 for rapid dispatch to any location. Their missions cannot be delayed, restricted, or aborted by blocked air intake filters, so they require a maintenance free engine protection system.


The fit and forget PUREair system, historically also referred to as a "sand filter", "Centrisep" or "inertial particle separator", is the perfect solution for such challenging operations. It shields the engine against airborne contaminants, which results in:



The fit and forget PUREair system, historically also referred to as a "sand filter", "Centrisep" or "inertial particle separator", is the perfect solution for such challenging operations. It shields the engine against airborne contaminants, which results in:

  • Increased operational availability and reduced downtime
  • Safer operation (protection against foreign objects, ice, snow, and rain)
  • Protection against engine erosion
  • Reduced maintenance and operational costs


Improved Helicopter Flight Safety


The PUREair system is located in front of the engine air intake and offers excellent protection against airborne sand and dust, foreign object damage, heavy rain, snow, and ice. The system prevents catastrophic engine failure, engine flame-out, and blockage of the air intakes.


Each design can be certified for inadvertent entry into icing conditions. Some models have undergone winter trials and have subsequently been qualified for all-weather operation.


The PUREair system does not become blocked and therefore has no requirement for a bypass system and warning lights. In contrast, oil-wetted IBFs require bypass systems. This increases the complexity of the design, adds additional inspection and maintenance costs, and can increase the pilot’s workload. A bypass door can also collect foreign objects, sand, ice, etc., which may go straight into the engine intake when the door is opened.


State-of-the-Art Removal Efficiency


Pall’s latest PUREair designs have excellent sand and dust removal efficiency. A particulate removal efficiency of greater than 96% (ISO Coarse Test Dust) by mass will provide an increase in engine erosion life of over 20 times.


Field experience, including trials in the Paris-Dakar rally, has shown that this level of removal efficiency is more than adequate to protect the engine from erosion damage and to meet the required time between overhaul (TBO.)


Protection Against Helicopter Engine Erosion


The PUREair system is very effective at removing fine sand and dust. It can increase the erosion life of critical turbine components by up to 20 to 30 times compared to an unprotected engine, without introducing any additional maintenance burden on the operator.


  •   Engine power loss (compressor erosion or damage)
  •   Blade corrosion
  •   Turbine blade glazing
  •   FOD or bird strike damage 


Solution – the PUREair system
 Increased operational availability & reduced downtime


  •   Increased engine reliability
  •   Safe operation
  •   Protection against engine erosion
  •   Reduced maintenance & operational costs 


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Helicopter Engine Protection

Increased Operational Availability and Reduced Downtime

Why Choose PUREair?

PUREair engine advanced protection system (EAPS) offers the ultimate in helicopter engine protection.

For decades, the PUREair, also known as a ‘sand filter’ or 'EAPS,' has proven very effective in extreme sand and dust conditions.



  • Increased Operational Availability and Reduced Downtime
  • Improved Helicopter Flight Safety
  • State-of-the-Art Removal Efficiency
  • Protection Against Engine Erosion
  • Reduced Maintenance and Operational Costs


Designing helicopter engine protection systems is a complex process that requires considerable expertise.


Pall engineers provide design and testing services  to deliver cost-effective engine protection for a wide range of helicopter applications on thousands of helicopters around the globe.



Increased Operational Availability and Reduced Downtime


PUREair is a self-cleaning system. Contaminants are continuously scavenged overboard which means that the system has an 'unlimited' dirt-holding capacity, unlike barrier filters, where service life is determined by dirt-holding capacity.

The system is extremely effective in sand, dust and brownout conditions. In a laboratory test at MTU Aero Engines, the Tiger PUREair system was challenged with 156Kg of dust. This is equivalent to 10 (ten) hours in brownout conditions. The Pall system stopped virtually all of the contamination from entering the engine, and operated continuously throughout the duration of the test. In contrast, an oil-wetted inlet barrier filter (IBF) would have required cleaning 300 times and replacement at least 20 times during the equivalent test period. This means the test would have stopped every two minutes for barrier filter maintenance.


For decades, the PUREair system has proved invaluable to commercial and military operators around the world flying in severe operating environments.


Reduced Maintenance and Operational Costs


The PUREair is a ‘fit and forget,’ environmentally-friendly system. There are no barrier filters to clean and replace. It is virtually maintenance-free and there is no need for any oil-based cleaning solutions that are difficult and expensive to dispose of.

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