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Hold the salt: Donaldson IFBs keep helicopters safe

September 30, 2013  By Carey Fredericks

London, U.K. - Recent testing by Donaldson Aerospace & Defense has demonstrated the ability of its Inlet Barrier Filter (IBF) systems to prevent airborne salts from degrading the performance of helicopter turboshaft engines and increasing their maintenance costs.

Turboshaft engines on helicopters flying low or hovering over the
ocean and coastal and inshore regions ingest airborne salts that combine
with the heat of their turbine sections to corrode blades and other
components and increase exhaust gas temperatures. Missions that expose
engines to salt-laden air include firefighting, offshore transport,
search and rescue operations, anti-submarine and port security patrols,
and vertical replenishment work. Exposure to these environments
increases the need for aggressive engine washing, reducing aircraft
availability; it also drives up maintenance and overhaul costs of the

Donaldson, which for several years has investigated how
salt ingestion affects helicopter engines, recently concluded a series
of extreme tests that exposed an IBF-equipped engine to a high-volume
sea water spray. The test used a wind tunnel with a sea water injection
system coupled with an aerodynamic particle-size analyzer and a flame
photometer to maintain and verify the size and concentration of salts in
the airflow.

At the system's designed test airflow, more than 115
grams of salt was fed into the engine filter. Previous engine testing
had demonstrated that the ingestion of 30 grams of salt could lead to a 9
percent increase in exhaust gas temperature. The recent testing showed
that the oiled filter media in Donaldson IBFs – which today fly on
thousands of civil and military helicopters worldwide – allowed 4.5
grams of salt to penetrate the IBF. This salt capture prior to turbine
entry can reduce the damaging effects of salt ingestion on an engine.

The positive test results reinforce the benefits reported by many Donaldson maritime IBF operators worldwide over the years.


IBF systems can keep helicopter engines on a salt-free diet," said Eric
Erickson, General Manager at Donaldson Aerospace & Defense in St.
Louis. "This recent testing demonstrates our commitment to ensuring that
Donaldson's customers can perform a wide range of critical missions
reliably, affordably and safely."


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