Home-United StatesRam air inlet receives filter system upgrade

Ram air inlet receives filter system upgrade

By Peggy Mills,

If you currently have a Thrush aircraft with a Record Pitot-type engine air inlet installed per STC SA4374NM, there now is an optional Quick Change Air Filter System available from Aero Innovations, LLC based in Terre Haute, Indiana.

Aero Innovations purchased the Record Intake STC in 2015. The STC was originally issued in 1988. This was one of the earliest pressure cowlings made available for turboprop-powered agricultural aircraft.

The STC allows for the installation of a pitot-type engine air intake on S2R-T34, S2R-T15 and S2R-T11 Thrush aircraft.  This type of intake maximizes the effects of ram air begin delivered to the engine compressor by increasing the air pressure inside the intake. This increased pressure reduces interstage turbine temperatures (ITT) and allows for an increase in torque. This can result in a lower Ng, which enables the engine to work more efficiently. Fuel efficiency is also increased.

The STC was originally designed with an air filter that was very time consuming and cumbersome to access for cleaning or replacement. This involved removing the front cowling, dropping the scoop and disassembling. During this disassembly, the RTV/silicone seal would have to be removed. The filter element was then cleaned, reinstalled, resealed and the cowling reassembled. This task could easily consume half a day or more of an operator’s time. This original filter assembly is no longer supported.

A replacement filtering system is now available for the STC’d intake. The replacement, known as the Quick Change Power Filter System, is assessable through an external door located on the right side of the intake cowling. The filter assembly removal and re-installation can be as simple as changing a home furnace filter.

The removable filter housing consists of eight filter elements. Cleaning is recommended at 100-hour intervals (more often in high contamination locations). Filter elements should be replaced at 1,500-hour intervals.

Cleaning the elements is easy. Tap the filter assembly lightly to remove excess dirt from the elements. Spray the elements with filter cleaner and allow to soak for 15 minutes. Thoroughly rinse, allow filter assembly to dry and then lightly re-apply the specified treatment oil.

Installation can be accomplished by the removal and shipping the lower cowling to Aero Innovations in Indiana. It takes approximately 10 days to 2 weeks to complete the installation. Then, the lower cowling is returned to the operator for mounting on the aircraft.

Aero Innovation’s Quick Change Power Filter System is a simple and economical way for operators to save time and money with their Record Intake filtration system.


The filter cavity before installation.


Here, the cleanable and reusable filter is inserted into the lower cowling of the Thrush aircraft.

The old style filter (left) that is replaced by the new style filter element (right).



Aero Innovation’s Quick Change Power Filter System ready for return shipment to the customer.


The filter cavity mounted to the lower cowling while being fitted to a Thrush airframe.




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