I noticed confusion and misinformation in here, so I thought I would clarify some things.
Some notes about The New Collision avoidance units, and a copy of an article. I did some research and found that the Avionics West Review was done by someone who bought a used unit off of another pilot (Not very smart if you are going to write a review on it since you have no idea what condition it is in, you would think they would buy one from the factory??) They took it apart to photograph it obviously. Wonder if this could affect performance if someone who doesn’t work for their company takes a screw driver to it? I wouldn’t put much faith in that article, especially since the guy sells their competition. It looks to me like they are passing a slam-ad off as a “product review” to get more attention to the brands they DO sell. As far as the Monroy unit, I know both SureCheck and Monroy sent their products to Sporty’s for evalutation. Sporty’s rejected Monroy’s and took SureCheck TPAS to sell through catalog and use in their sweepstakes aircraft.
Here is a copy of the article mentioned…
TPAS vs.TCAS
Collision avoidance and the new era. SureCheck Aviation, Inc. gets the industry talking with its first portable anti-collision product.
Since the 1956 mid air collision between two airliners over the Grand Canyon, the aviation industry has sought an effective way to counter mid air disasters. Efforts to resolve the problem of air traffic collisions and near misses became crucial after a 1978 collision between a single engine aircraft and an airliner on approach to San Diego International airport. Finally in 1986 near Los Angeles Airport, a collision with a private aircraft and a departing airliner, prompted congressional legislation to mandate Traffic Alert/Collision Avoidance Systems in Commercial aircraft.
Modern TCAS is a complex system, which involves manipulation of an existing RADAR system known as “ATCRBS” or secondary RADAR that interrogates your transponder. The system operates by use of many methods, however the way in which general aviation aircraft are “seen” by TCAS is often through interrogation much like existing Ground RADAR facilities have done for years. The difference is the processing of the information once received. This is not as simple as one might expect. There are many problems that exist when multiple aircraft are interrogating multiple transponders. Several years and software upgrades have yielded sometimes reliable, sometimes no so reliable results. The highlights of TCAS are the ability to locate transponder equipped aircraft, range them, differentiate host aircraft to intruding aircraft and display this into useful information to give a pilot independent traffic resolution beyond ATC. Without diving into the vast technical problems engineers faced when coping with multiple transponder replies and RF / microwave behavior with respect to reflection, it is important that pilots know and understand that even the best systems still today have “bugs” which will require technology that is still down the road to come. The good news is, that over time the reliability has become such that pilots today feel safer flying with a TCAS system than without. Now the real problem. Price. A typical installation can easily reach $100,000.00 per unit! So unless you plan on doubling the value of your aircraft for one piece of avionics equipment, this is not a viable option. New versions have emerged in the TCAS market, which have proven less cost prohibitive, and as of today a good active system will run you near $20,000.00 and up. Now this may reach many pilots who feel this price is worth the security for the present technology offered, however to the average pilot, who makes up most of the aircraft flying today, this still is not a realistic option.
So why is TCAS equipment so expensive? The reason is actually simple. Complexity. 90% of the software involved with Collision avoidance equipment is filtering out potential false alerts. The beacon RADAR system, ATCRBS, was not setup to be used as a collision avoidance tool. The other side of the expense is the engineering skills required to design and maintain upgrades are not only rare, but experience required is a must.
With improvements in semiconductor, processors and RF / microwave products, a new era of collision avoidance has entered the market. The TPAS®, designed by SureCheck Aviation, Inc. became the first truly portable, basic collision avoidance system. TPAS stands for Traffic Proximity Alert System. So what is the difference between TCAS and TPAS? Why such a cost difference? As mentioned before, TCAS is an active system, which interrogates other nearby transponders and process information accordingly. The TPAS system eavesdrops on these replies generated by not only TCAS systems, but Ground RADAR facilities as well. Without the need to transmit interrogations, TPAS avoids tremendous costs, and being portable the costs drops even further. But not interrogating other aircraft has its drawbacks. In a non-RADAR environment, where neither TCAS systems are operating, or Ground RADAR facilities are in range, replies cannot be heard. The reason TPAS is viable today however is because of the vast improvements of RADAR installations. Today’s coverage of Beacon RADAR systems is vast and covers even the most remote areas very well with altitude. Some limitations begin to occur when aircraft enter areas well shielded from such facilities, but even these holes continuing to be filled with RADAR services yearly. As mentioned before, TPAS also accepts replies generated by TCAS equipped aircraft, so valleys and shadows can be illuminated by even one aircraft such as an airliner operating at 30,0000 feet overhead. The TPAS system listens for the different kinds of interrogations, such as either ground or TCAS and displays to the user a constant indication of whether he is in a RADAR environment or not. This is one of the most important features, since the accuracy depends on a live RADAR environment, even if slight which one cannot gather from watching a transponder reply light alone. This light although sometimes useful, differs with different brands and in some cases only indicates if a valid signal has been received, not transmitted. In some cases where TCAS is active one may not even see a reply light because it is so short, and without this feature pilots would not know whether or not traffic could be detected. The TPAS system displays Traffic in estimated nautical miles, based on internal computations and variance factors, within 1800 feet of the host aircraft. Aircraft are sorted by priority and displayed accordingly. When an aircraft lands or is no longer a threat, TPAS switches to display the next closest threat. Two modes of operation are another important issue, since aircraft operate in two completely separate regions of potential conflicts. The first being an airport area where density is higher and separations are less. TPAS is designed to recognized potential conflicts and alert the pilot when an intruding aircraft meets criteria suitable for an airport environment. The second mode of operation, enroute, covers the phase of flight where air traffic is at it’s greatest speed and separation distances. The importance of this completely separate mode and alert criteria is to enable the pilot to see aircraft at a further range, up to 10 NM, and allow suitable time for reaction and decisions. Another mode, which serves to protect the receiver and reduce false alerts, is the ground or Standby mode. This keeps high output microwave energy generated by various RADAR or Weather systems from damaging the sensitive circuitry. The drawback of this type of collision avoidance unit is directional information. The concept behind TPAS is to raise traffic awareness to a pilot by acting as a second pair of eyes, eyes that can see around edges and corners and whose sole purpose is to scan for traffic. The addition of directional equipment would not only possibly inhibit portability (thus raising cost significantly) but also require an installation to accommodate various antenna configurations. Although SureCheck Aviation is working hard to produce such technology into a portable product, it proves to be a great challenge. However, with experience and use, pilots who use TPAS many times are able to discern direction based on closure rates. Obviously an aircraft coming towards you from the front will result in a fast closure rate whereas traffic from the rear will tend to “stick” near a mileage point until it slips out of range. Is it worth saving $19,400??? That is up to the user, however for pilots who rent, or do not have a spare $20K, this is by far a good step in the right direction of increasing traffic awareness.
With years of engineering, TPAS yields the following features.
· Completely Self-Contained
· Traffic detection up to 10 NM
· Range selectable, from Terminal (5 NM) to Enroute (10 NM)
· Audible alerts for Traffic Advisories and Traffic Alerts
· Visible warning system similar to TCAS
· High-brightness LED 2-digit display
· Digital range accuracy
· TCAS and Ground Radar Interrogation Indications. Know if you are in a RADAR coverage instantly, or if you are being watched by other aircraft using TCAS
· Auto intensity light for day or night operations
· Adjustable volume and mute
· On-board test function with audible confirmation
· Compact adapter included or 6 AA batteries
· 12 or 28 volt system compatible
