This site will serve as a showcase of delevopments in runway incursion prevention in the Northwest Mountain Region, based on the work of Clark Eastman (FAA) and Jon Chandler (Clever4Hire).  This is the team who developed the WTT4 and WTT5 Wake Turbulence Timers in use in the Northwest Mountain Region.  Click here for more information on the timers.

New Project Developments - Radio Interface Front Panel   2/13/2017
                                                       System Network Design      2/16/2017  - updated 2/21/2017
                                                       Remote Units - Network Creates Flexibility    2/20/2017

                                                       Note: rather than revise all the pages here as changes are being made,
                                                       I am adding links to information showing how the network is evolving.  
                                                       What was a prototype concept is rapidly morphing into a full-featured 
                                                       system that will serve the current needs and allow future growth in both 
                                                       size and function.

Steps to go From Demonstration System to Working System

The prototype system has served to develop firmware to control the system and demonstrate the technology.  The steps to build an working system are pretty simple and straight forward.

Display/Control Unit

The demonstration Display/Control unit is a stand-alone enclosure.  The replacement system will be designed to mount in the console in place of the existing RID systems.  The Display/Control unit will be designed similarly to the WTT4/WTT5 Wake Turbulence Timers, using an acrylic panel secured to the console.  The form factor will be changed to fit in the existing locations.  A new circuit board will be laid out to fit the form factor, incorporating some changes to make fabrication easier.

The panel is hard-coat acrylic, with labeling engraved on the back side.  This material has held up well with in the wake turbulence timers; customary aluminum panels have paint wear-though from frequent touch while the acrylic panels are pristine with the same amount of use.

The prototype used an audio alert that announces "caution"; these modules can be purchased with the desired phrase, but instead we will use a module which plays MP3 files with good fidelity.  This will allow easy customization if needed at a similar cost.

The prototype Display/Control unit is shown below.

Display Remote Unit

The existing RID systems have remote display units that include only the indicator lights.  We did not develop a remote display in the prototype system but this is easy enough to add.  If the remote is to be console mounted, its construction will be similar to the main Display/Control unit.  Alternatively, the remote could be a weatherproof device for use in exposed locations.  Any number of remote units may be daisy-chained from a main unit.

Radio Interface System

The prototype system has proven itself.  It will be mounted in a 19" 1U rack enclosure for the working system.  This will require laying out new circuit boards to fit the enclosure to allow indicator LEDs on the front panel and radio connections on the back.  No problems are anticipated in changing the format.

The photo below shows the prototype radio interface system.  The square boards on the left are the interface boards - each board supports 8 radios and up to 4 boards may be used in a system (32 radios).  Below this is an illustration of the system in a rack enclosure.

Radio Interface in Rack Enclosure - Front View

Radio Interface in Rack Enclosure - Back View

Upgrade to the Radio Interface / Display/Control Communiations

The following paragraph superseded.  Please click here for the latest refinement

The prototype system uses a simple 4-bit digital signal to indicate when radios associated with a zone have been keyed.  This arbitrarily limits the system to 4 zones, which is what the current RID systems support.  I will investigate using RS-422 serial as a preferable interface system.  Eight or more zones could easily be supported with this simple change.  Each Display/Control unit works with 4 zones, but those zones can be defined for each unit.  For example, one Display/Control unit could be configured to cover 4 runway restricted zones, while another could be configured to cover 4 taxiway zones.  The zones are configured in software using a simple procedure, allowing the configurations to be changed as needed.


This prototype system exists and is functional.  While being a slight enhancement over the existing RID systems, it provides significantly enhanced safety with little change in operating procedures.  This system also has the advantage of being microcontroller based - it's a simple matter to alter the way it works to fit into work flow and operational needs.  It's not hard-wired to the initial design and stuck if something doesn't work quite as planned.

This technology is proven, reliable and long-lasting.  It should last the 10 years desired and many more, but if parts fail, it's based on readily-available components so it can be repaired if necessary.