I certainly agree with your assessment, and not flying with parts or equipment that do not meet the standards. i also have 3000+ hours in bell 206/407/58D. understanding the system and the way in which the cockpit indicator operates is very important in determining whether the aircraft can be flown safely to a maintenance facility or if it needs to be grounded on site. the IBF's are essentially the same as most other types of air filters you might see on a car or in a house. They physically trap dust, dirt, birds, snow or anything else that may attempt to reach the compressor inlet. In the cockpit, most of these aircraft will have a Clog/Bypass switch or indicator to alert the pilot when not enough air is getting thru the filter. It operates on differential pressure and will typically have a static port on the plenum side, and another static port on the outside of the filter housing. When the air pressure inside the plenum drops to a predetermined value, it triggers the Clog light, and the pilot will immediately see that the filter requires service... most often, this is accomplished by "banging out the filter" for a lack of better terms, re applying the filter oil, and reinstalling the filter. Very simple work really, and if operating in the bush, or in the desert, the pilot might want to be familiar with this procedure. So... you have now found yourself in a position where you have the filter light "ON" and you need to return to base, or finish the job. obviously step one is to try simply knocking the dirt out or checking for larger debris, after that, try running a Health Indicator Test(HIT) check. determine if the engine TGT or TOT is still operating better(cooler) than spec, or if it is running hotter than allowable. This will allow you to at least note how much deterioration the filter has caused, if it doesnt pass the Health check, it doesnt fly home, period. If it does pass, it indicates that the filter is allowing enough breathing air to keep the engine cool and that the filter is likely just over the indicating limit for differential pressure. please keep in mind that this post is designed to educate the individuals interested, and assumes maintenance support is not available. It is also written from the mindset of a military pilot, who has been forced to fly these types of filters in very harsh desert conditions. landing in Iraq due to a dirty filter just isn't an option. knowledge of the systems, and a healthy understanding of engine performance will go along way in this scenario. When in doubt, dont take the aircraft!!!