Chief Inspector, AgRotors, Inc.
August 13, 2003

Aircraft Services, Southern California Edison
January 01, 2003

Chief of Maintenance, Helicopter Division
January 29, 2002

Deputy Chief, Air Operations U.S. Border Patrol
May 28, 1997

David Sellars
Chief Inspector, AgRotors, Inc.

August 13, 2003

We are a helicopter service company whose main operation is agricultural spraying. Most of our work is done from remote sites in sometimes less than perfect conditions. Due to the harsh working conditions of our aircraft operations we were forced to drop the manufacturers compressor case half inspection from 1750 hours to 300 hours of operation. One of the reasons for this was, the compressors were not making it to their recommended overhaul limit. We found that if we would use the recommended coating for the case half lining, and applied it often enough, the erosion from the dust and dirt getting past the "improved particle system" would be held down to a minimum. In doing this, the compressor had a better chance of making it to overhaul. The second reason was it gave us a look a the compressor blades often enough, so that we could run the unit until it failed wear limits or it would not produce rated power, which ever came first.

Around 1998 we decided to purchase the "Eliminator" engine air filtration system (EFS) for one of our Bell 206 helicopters. We then installed the unit on an aircraft with a fairly new compressor on it. We ran the system for one season in a very dusty environment. After the season, we inspected the case halves on this aircraft. The results were so positive that we outfitted all of our 206 & OH-58 helicopters with this filter system. These filters replaced an IPS system on each aircraft. It was a costly endeavor for a small company like us, but it has proven to be a "savior of dollars" by far. We have five 206's and 2 OH-58's.

We have since changed our requirement for case half inspection from 300 to 600, which is sooner than the recommended limit, but some habits are hard to break. We also no longer have to worry about a compressor making it to overhaul limits, it is just expected

The units are a little more maintenance intensive than the basic inlet or IPS inlet system, but in the end well worth it.

David Sellers
Chief Inspector
AgRotors