Military, Regulatory

U.S. Navy’s T-REX at Large

By By Douglas Nelms | November 1, 2010
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The U.S. Navy has begun rotorcraft project testing using its new Testbed for Rapid Warfighter Response and Experimentation (T-REX), a Bell UH-1N adapted for use in developing and testing new technology equipment. T-REX is a part of NAVAIR’s Naval Aviation Center for Rotorcraft Advancement (NACRA), and headed by Brad Schieferdecker, associate director for technology development, and based at NAS Patuxent River’s HX-21 experimental test squadron.

Shortly after arriving at Patuxent River, T-REX was used to conduct regression testing for the BRITE Star II, which is the latest generation FLIR to be fielded on the UH-1Y and UH-1N. Additional testing in support of the UH-1N fleet included A.2.4 CDNU software for the control display navigation unit. Without T-REX, the testing would have been conducted out in the fleet, Schieferdecker said. The regression testing was to determine that new programming did not adversely affect the old programming or functions.

In June NACRA held the preliminary design review for the instrumentation package going into the aircraft. “The instrumentation racks have been fabricated and the aircraft will undergo modification in October to install additional provisions including crashworthy seats in back for the operators of the systems,” he said.


The first full project was completed last August—an evaluation of the Zaon XRX Portable Collision Avoidance System (PCAS), Schieferdecker added. This is a very small (3.9” x 3.6” x 2.7”) “plug and go” commercial off-the-shelf (COTS) air-to-air collision avoidance system being looked at because of incidents involving near-midair collisions, Schieferdecker said. “This is a passive system that is cheap, only $1,500 a copy. It is looked at as a potential CONUS solution for near-term collision avoidance capability.” NACRA completed two ground events and three flights with T-REX for the Zaon system, he said. The testing was requested by the Marine Corps’ Aviation Weapons Systems Requirements branch.

T-REX is currently being used for testing of the Sandel Avionics ST3400H HeliTAWS, a combined helicopter terrain awareness and warning system and ground proximity warning system (GPWS). “Some of our aircraft will be in service for another 10 years and have neither HTAWS nor GPWS,” Schieferdecker said. This testing is also being conducted in support of APW. NACRA recently executed a cooperative research and development agreement (CRADA) with Northrop Grumman to put an AH-1Z Gen II mission computer in the cabin of the aircraft. This is the upgraded version of the same system that is in the AH-1Z Viper, “and will allow test integration with minimal changes to the systems avionics or the aircraft,” he said.

“It will serve as an enabler for economical integration and evaluation of other systems in a representative flight environment,” he added. The aircraft is currently being equipped with all of the necessary testbed capabilities, to include quick disconnects for antennas, Mil-Std-1553 databus, AC/DC power, GPS and the sensor. “The goal all along has been to do S&T [science and technology] work on the aircraft, those types of projects that haven’t been considered for a program of record. We’ve done well in achieving flight clearances in a pretty rapid fashion, and we’re working to execute the projects with the biggest potential impact,” Schieferdecker said.

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