Portable test equipment, with its ability to improve safety and on-time performance for commercial and military aircraft, is a key component of any operator’s maintenance shop.
Capitalizing on advances in consumer technology, new portable test and ground support equipment (GSE) is designed to be smaller, lighter, more ruggedized and less expensive. Designers are tasked with making systems flexible — capable of testing, simulating and verifying avionics on the flight line or in the hangar, base or shop — and in some cases combining multiple test functions in a single unit.
Doing more with less is a common theme among developers of avionics test equipment. William McRae, data products manager for TechSAT North America, based in Seattle, compares his company’s data loader and analyzer products’ flexibility to the Swiss Army Knife.
"To communicate with an aircraft for data loading generally requires that your piece of GSE have databus resources required to talk to the airplane’s own databus," McRae said. "But those same resources are capable of supporting many other applications other than data loading. It can be an analyzer, test a particular system on the aircraft, or provide a simulation that allows other tests to be performed on the airplane.
"If you have a piece of GSE that has one purpose and that provides the host and the databus-required resources, when you start adding additional applications, it makes that piece of hardware an incredible value because you are spreading the cost of what would be a single piece of equipment and now getting a piece of GSE that may support multiple different things."
Parent company TechSAT GmbH, headquartered in Poing, Germany, supplies portable data loaders and analyzers based around commercial off-the-shelf (COTS) ruggedized PCs, along with mobile simulation systems and software for current and next generation aircraft.
The company provides test and integration tools, including test systems and software, for the Airbus A350; data loading tools for Boeing 787 suppliers when equipment is being developed and produced, and shop data-loading systems for airlines. TechSAT also supports military transport aircraft, including the Airbus A400M, designed for multiple crew members and having similar navigation and cockpit management problems as commercial airliners.
Being involved earlier in the aircraft development process is becoming more common for GSE developers, McRae said. "Our philosophy is that the equipment used during development, test and integration is the exact same thing that ultimately needs to be used to maintain the airplane," he said. "We like to have our stuff used by the developer and that, in turn, gets rolled into manufacturing. When the airplane is actually produced, these same tools are rolled out to the end users, the guys on the flight line."
TechSAT tools and software are designed for all applications — flight line, hangar or repair shop maintenance. The company started in 1986 developing databus products, and then moved to large-scale test systems, including cabin test systems for the Airbus A380. As a result, McCrae said, databus products and simulation designed originally for testing, development and integration, are now utilized to make ground support equipment as well.
Test and measurement systems supplier Aeroflex, of Plainview, N.Y., has added new products and capabilities, such as combining the functionalities of several systems into one box. In April, the company added IFF test modes 1, 2 and TACAN as standard features to its IFR 6015 transponder ramp test set. "This box actually replaced three of our former ramp boxes and put three units into one smaller footprint with longer battery life and better serviceability in the field," said Brian Schirer, Aeroflex avionics business development manager, based in Wichita, Kan.
The company’s IFR 6000 test unit, which weighs eight pounds and has a 6-hour battery life, is targeted for commercial airlines — 41 airlines in the Americas use the system — to test aircraft transponder Modes A/C/S, Traffic Collision Avoidance System (TCAS) I and II, distance measuring equipment (DME), Automatic Dependent Surveillance-Broadcast (ADS-B) and traffic information service (TIS) systems. Airframe manufacturers, including Boeing and Airbus, also use it in final acceptance testing, Schirer said.
Other Aeroflex products include a portable navigation/communications tester — the IFR 4000, which is designed for testing ILS, VOR, marker beacon and VHF/UHF communications systems; the GPS-101, which tests GPS receivers by simulating a satellite and generating a specific satellite and navigation data pattern; a portable ARINC 429 databus tester; and a line of fuel quantity test sets.
In addition to being involved in the aircraft design process, customer demands for these types of test equipment systems are changing, suppliers said. Flexibility and scalability are necessities as companies look to upgrade or add to their systems.
"In the past, they (customers) would like a system to do what they want and nothing more," said Doug Ullah, director of sales and marketing for AIM GmbH. "But what we are finding now is we have to develop products [that are] scalable and modular and that give the customer what he wants today, and then you can add both hardware and software to upgrade or retrofit to fit a whole range of needs depending on the aircraft."
Ullah added, "People have to spend money wisely now. When they do buy, it has to work today but also next year. I will upgrade my system that has a 429 (databus) in it today, but what happens if I need a CANbus tomorrow?"
AIM GmbH, based in Freiburg, Germany, provides scalable and modular hardware and avionics databus systems in commercial off-the-shelf (COTS) PCs for portable test applications. AIM’s PBA.pro databus test and analysis software system covers a range of applications from a standalone databus analyzer to a complete systems test bench or advanced avionics integration facility.
Further emphasizing the importance of flexibility in portable test systems, David Leslie, chief marketing officer with GE Sensing and Inspection Technologies, said, "I think of it in three ways: it is used at the ramp, the shops or the base."
GE Sensing and Inspection Technologies, based in Billerica, Mass., provides avionics test and inspection equipment, including air-data test systems (ADTS), pressure and temperature sensors, angle-of-attack and cockpit systems testing, and pressure and temperature sensors for engines, cabin pressurization, fuel and hydraulic systems and landing gear.
A number of company acquisitions since 2001 have added to its product line. The company’s ADTS 405F flight line variant is used by commercial airlines and military customers to test the pitot static systems on aircraft. A key stimulus to that product, which is sold to both aircraft manufacturers and airlines, was the introduction of reduced vertical separation minimums (RVSM).
"The (RVSM) rules require highly accurate calibration of the pitot static systems to make sure that the plane is within plus or minus whatever feet of where it is telling the pilot it is," said Leslie.
Last year, the U.K. Ministry of Defense placed a $3.6 million order for an additional ADTS from GE for military aircraft maintenance and flight checking in the Royal Air Force, the Royal Navy and Army Air Corps, complementing the 173 ADTS test sets already operated by the three branches of the armed forces.
Nav-Aids Ltd., based in Montreal, recently was awarded a contract from EADS-CASA, of Seville, Spain, for air data test adaptor and connection tooling kits for the Airbus A400M. Nav-Aids said the four Air Data Accessories Kits, consisting of pitot and static probe test adapters, test hose assemblies and accessories, will test and verify the A400M air data systems while the aircraft is being assembled and flight tested at the EADS-CASA final assembly facilities in Seville.
CAST Navigation, Tewksbury, Mass., produces GPS receiver test and simulation systems, including portable flight-line testing systems. The company originally built simulators to help with software development. Today, CAST Navigation sells a portable GPS simulator in two different models — one for the military called CAST 1000, and one for the commercial market called SIMCOM. The CAST-1000 can generate a full GPS constellation with 8 to 16 satellites in view. It is designed with preferred Windows and Lynx operating systems.
CAST Navigation also builds portable test equipment for the embedded GPS/INS (EGI) receivers that can be taken to the flight line for testing and reloading of software without removing boxes from the aircraft, said Lou Pelosi, vice president of customer service. CAST Navigation has worked with EGI producers Honeywell and Northrop Grumman to develop the flight-line test package called the EMT-3500-1, which is for military applications now, with its main customer the U.S. Air Force.
"It reloads software for the embedded GPS system, and many times that corrects the problem," Pelosi said.
Test Equipment Case Study: Alaska Airlines
Alaska Airlines operates a varied fleet of 116 Boeing 737s, including -400 Classics, Next Generation -700, -800 and -900s, 737-400C passenger and cargo "combis" and a 737-400F freighter. It uses portable test equipment for flight-line maintenance and for heavier overnight maintenance at its Seattle base and at other West Coast locations. In addition to Seattle, it has line maintenance technicians in Anchorage, Juneau, Portland, Los Angeles, San Francisco, Phoenix and Orange County, Calif.
The airline farms out its heavier maintenance checks to vendors, and contracts for line maintenance at airports such as Miami where it has fewer flights. Of its 650 technicians, 120 are primarily involved with avionics troubleshooting and repair, according to Scott Williams, Technical Training instructor in Seattle.
Alaska Airlines has around 50 different types of test equipment for avionics, and purchases its equipment from a number of vendors. Aeroflex supplies IFR 6000 transponder test units to the airline; two are located in Seattle and one in Anchorage.
"It doesn’t matter if you are troubleshooting or doing a task card, generally you are going by the Boeing manual list of equipment which is authorized for that procedure," Williams said.
"We can alter that, depending on approvals, but at least we have a list of equipment that’s authorized — that’s kept in stock in the tool room."
Most of the test equipment Alaska Airlines uses is "reasonably portable," Williams said, and includes NAV/COMM/DME testers, air data (pitot static) testers and fuel quantity testers — enough equipment to deal with problems encountered on a through flight or for overnight maintenance.
The equipment is used "when we have discrepancies," Williams said. "We have very few work cards that call for periodic checks on that kind of equipment. It’s in response to a write-up. And then we use whatever is the authorized equipment for it."
The test equipment used on the flight line is also used, housed in another case, in the shop for calibration, he said.
The biggest need Williams sees now in airline maintenance is for equipment to download flight data information.
"We’re looking at something to download data off the DFDAU (digital flight data acquisition unit) in a way that makes it portable," he said.
"Now you have to put it on a disc. There are times when we want to download that info at an out-station, and would like the ability to hook it up to a network or on the Internet and just transmit the data. We have tested several pieces (of equipment) but haven’t found anything suitable yet." — James Ramsey