FRDS Gen 2 components

The first generation FRDS system has been around in one form or another since 1991. The system has been continuously upgraded over the years to add features and reliability. All of this ‘feature creep’ made the system more and more complex and in some ways more unreliable and complex than it should have been. Couple that with poor maintenance in the field and a growing number of components being obsoleted by various manufacturers and you’ve got a pretty good reason to do a ground up redesign. At some point in 2005/2006 Air Tractor decided it was time to move forward on the Fire Retardant Dispersal System Gen 2 and who better to design the system than the guy who built the first one?

Enter a few hours of work and you’ve got the new FRDS Gen 2 system. Its triple redundant and should be much more robust in the field through all the lessons learned from over 15 years of development with the old FRDS system. It is currently undergoing FAA testing and check out; if all goes well it is scheduled to start shipping on aircraft at the end of this month.

Pilot Interface:
This is the control system for the fire gate that the pilot interacts with. In the old system this was just a HMI (human machine interface) with no real smarts. All of the smarts lived in a large PLC enclosure in the aft of the plane. The Gen 2 system has its main smarts in the pilot interface in a series of custom PCB’s designed by the company I work for. This was done mainly to keep the smarts of the plane in a cleaner environment away from fire retardant and regular plane wash downs.

The custom enclosure and artwork were designed by me.

Relay Box:
This enclosure, dubbed the ‘relay box’, sits in place of the old PLC enclosure for the old system. This box looks similar, however it is slightly smaller and significantly lighter. Inside this box is where the 3rd tier of the triple redundant system lives. Should the 2 systems in the pilot interface fail, this system, the ‘electro-mechanical’ system takes over and fires the valves to open the doors. There is an entirely manual system that opens doors in the event all 3 systems fail or there is a loss of hydraulic power.

The relay box uses similar wire rope isolators as the old FRDS unit.

Side Loader Gauge:
This is a simple gauge on the side of the aircraft used by the person re-filling the hopper with fire retardant. It is water tight as it will be exposed to fire retardant every time the plane makes a drop, as well as aircraft wash downs.

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Monday, January 12th, 2009 at 10:00 am in category blog

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