Sandel awaiting approval for its TAWS with integrated RMI

 - July 14, 2008, 7:41 AM

Sandel Avionics of Vista, Calif., this month anticipates receiving the initial TSO and STC approvals from the FAA certifying the company’s ST 3400, a self-contained terrain awareness and warning system (TAWS) with integrated radio magnetic indicator (RMI).

Under development for the past two and a half years, the ST 3400 TAWS/RMI breaks into the market as only the third ground-proximity warning device in a field that should grow far more crowded between now and March 29, 2005, the date selected by the FAA for mandatory installation of TAWS equipment in all U.S.-registered turbine-powered airplanes with six or more passenger seats. The other certified TAWS products available for sale today are Honeywell’s Enhanced Ground Proximity Warning System (EGPWS) and the Universal Avionics TAWS.

FAA test pilots early this month were scheduled to fly a series of type inspection authorization (TIA) flights in a Cessna 421 owned by Sandel and used by the company for developmental trials of the product. Following issuance by the FAA of the STC in the 421, Sandel will seek additional STCs approving installation of the unit in the King Air C90 and 200, Citation I, Gulfstream I and Learjet 35 and 55 for customers in California, Florida and Georgia. Beyond this, the company plans to seek STCs for other models as customers purchase the equipment.

Greg Wilson, director of product marketing for Sandel, said the target market for the ST 3400 TAWS/RMI is in-service business jets and turboprops, although he added that the company has been in contact with OEMs, regional airlines and fractional providers that are interested in evaluating the unit. Sandel plans to begin a series of demonstration flights around the country later this month, said Wilson.

When the ST 3400 was introduced at the 2000 NBAA Convention, Sandel said it would be a class-A TAWS, meaning that it would meet the most stringent definitions of the TAWS rule affecting larger airplanes. Now, Sandel has decided to offer both a class-A and class-B TAWS, as well as a dual class-A unit. Uninstalled price for the single class-A system, said Wilson, is $34,500, while the class-B unit is priced at $28,200. The dual package for pilot and copilot side sells for $59,500, he said.

Wilson claimed the ST 3400’s display is three to four times brighter than the original SN 3308 EHSI and that the unit is 10 times more reliable, the result of advanced highly accelerated life-testing (Halt) screening in the design and validation of the system. Development of the ST 3400, he said, involved a series of modifications to Sandel’s original EHSI to make the TAWS unit’s display brighter and to increase its mean time before failure (MFTB), as well as a significant investment in Halt test gear. Sandel is so confident of the ST 3400’s reliability that it is offering a warranty that protects the unit for as long as the customer owns the aircraft in which it is installed.

Wilson pointed to the ST 3400’s compact size and competitive price as primary enticements to business aircraft operators who are searching for a TAWS solution to meet the 2005 deadline. In cockpits where panel space is limited or where TAWS-capable radar displays have not been installed, the ST 3400 serves as a “zero impact” solution, he said, meaning that it takes up no extra space in the panel because it simply slides into the spot already occupied by the RMI.

The terrain information is shown in red, yellow and green on the Sandel LCD, meaning that it does not need to share data with an EFIS or weather radar, as is the case with Honeywell’s EGPWS. This, said Wilson, also reduces installation time, which he estimates will be between 30 and 60 hr, depending on the airplane.

The three-inch display has a resolution of 300 by 480 pixels, providing a clear, crisp image on the unit’s glass. So-called “smart interface” technology allows the ST 3400 to interact with analog or digital cockpit equipment, making it a good solution for operators of older airplanes still flying with electromechanical equipment, said Wilson.

Several database options are available for use with the ST 3400, said Wilson, but he added that firm pricing for regional database updates has not yet been decided. Last summer Sandel signed an agreement with Jeppesen to use its proprietary worldwide terrain and obstacle database, which includes all mountains, hills and most obstacles, as well as airport information.

Buyers of the ST 3400 are given the option of a worldwide database or a database covering specific regions, including the Americas, Europe and Asia. Updates to the database, which Wilson said would be available either once or twice per year depending on customer demand, will initially be priced at $525 each. He added that this price might be adjusted in the future after Sandel has gauged buyer’s needs.

The resolution of the terrain database is 30 arc/seconds for most parts of the world and 15 arc/seconds near U.S. airports. Updates can be obtained through CD-ROM or over the Internet through the ST 3400’s USB port, located on the face of the display. Uploads do not require the unit to be removed from the airplane, and can be accomplished using a laptop PC.

The ST 3400 is being sold as a complete package, including the installation kit and harness assemblies. Together, all the components weigh 3.2 lb. The unit operates on 28V power and slides into a 10.5-in. mounting tray. The installation can be performed in two phases, allowing operators to install the display as an RMI first, and then go back and finish the TAWS installation later. Wilson, however, cautioned against waiting too long before having the TAWS installation work performed.

“We predict that there will be a rush of airplanes needing TAWS installed, and we don’t believe there is enough capacity, even starting today,” he said. “It won’t be like TCAS, where everybody waited until the last minute. Those people who do hold off [this time] will be caught short.”

The set of rules for installation of TAWS devices applies to turbine-powered airplanes with six or more passenger seats. Part 91 airplanes with between six and nine passenger seats can be operated with a class-B system, which is required to include only aural caution and warning messages. Part 91 airplanes with 10 or more passenger seats and all Part 135 and 121 airplanes with six or more seats must be equipped with class-A TAWS, which includes both aural and visual cues.