KLM Engineering & Maintenance

Air France Industries KLM Engineering and Maintenance Finds Low-cost Solution for Stringent FADEC Overhaul Requirements…   with Help from DIT-MCO International.

To overhaul or not to overhaul.

That was the question facing Air France Industries KLM Engineering and Maintenance as the Engine Control Units of its Boeing 737 Next Generation fleet neared the 30,000 flight hour mark. Outsourcing the overhaul of these units would mean great expense, long turnaround times, and a loss of revenue. But AFI KLM E&M didn’t have equipment that would allow them to meet the ECU vendor’s stringent testing requirements.

Fortunately, through thorough investigation and some clever engineering, AFI KLM E&M discovered a low-cost solution which would allow them to do the overhaul themselves – a solution from the same company the ECU vendor uses to test the units during manufacture.

A World Leader in MRO

AFI KLM is responsible for all MRO of its parent airlines’, Air France and KLM, vast fleet of aircraft. They constitute the 2nd largest aircraft MRO organization in the world, with a work force of more than 14,000 employees.

AFI KLM E&M is also a business unit, with a goal to not only serve its parent airlines but also to generate work from outside the company. AFI KLM E&M’s customers are mostly other airlines, both large and small. They also do occasional work on NATO military aircraft.

A Letter from the Manufacturer

As the first of KLM's Boeing 737 NG aircraft approached 30,000 hours of flight time, AFI KLM E&M looked into the overhaul of their engines and ECUs. What they found surprised them.

A Service Information Letter from the ECU vendor, FADEC International (a joint venture of BAE Systems and SAGEM), laid out requirements for a 30,000-hour overhaul and recertification. AFI KLM E&M found they would have to perform a complete wiring integrity check on the more than 2,000 pins of the unit's front and back panels. Many of the tests would involve high-voltage, and thus require special protection.

The magnitude of the circuit connections and measurements involved was unlike anything AFI KLM E&M had done before. They needed some sort of automated system, but had nothing of the kind on hand.

"We really didn't have anything capable of doing that," said Zafar Haji, a software development engineer in KLM E&M's Avionics Department. "You have a lot of solutions where you can switch measurements.  And you have instruments that can do high voltage.  But the combination was very difficult."

A Potential Lose/Lose Scenario

The situation was difficult for Haji and AFI KLM E&M. If they were unable to find a system that could perform the required tests in a timely, safe and cost-effective manner, they would have to outsource the ECU overhaul. For AFI KLM E&M, that represented a lose/lose scenario.

The first loss would result from higher costs. Outsourcing to another vendor would be very expensive. Plus, turnaround time would be longer. This would force AFI KLM E&M to stock additional spares, adding to both material and administrative expenses.

The second loss would be one of revenue. AFI KLM E&M would not be able to offer this overhaul service to customers. With more than 6,000 Boeing 737 Next Generations delivered or on order (according to Boeing.com), they would be missing out on a significant market.

Zafar Haji

A Painstaking Search… and a Lucky Find

Haji used the FADEC specification as the starting point for his search.

"At first, I was hoping the solution could be found with our own systems," says Haji. "Could I write the program and organize the system with hardware we already had? Unfortunately, we couldn’t, because we were missing some testing points. Also, the high voltage switching was a problem.  So, I started looking outside for other systems. But really, at that point, I didn’t have any idea in which direction to go."

Finally, after investigating many tools and options, Haji got a break. He found his solution within his own department.

"We do some repair for the military, on AWACS aircraft, and they had provided us a system called the DIT-MCO 2115, a very old one," said Haji. "My colleagues told me there are a lot of test points, and we could do high-voltage testing. So I  said, okay, I'll see what the specs are."

The DIT-MCO Model 2115 is a low-cost circuit analyzer that provides speed, power, reliability and ease of use in a benchtop configuration. Testing up to 1500V and 2 amps, the Model 2115 tests wiring and components for leakage, resistance, voltage, capacitance, and dielectric breakdown. All parameters are programmable, so you can use high voltage up to 1500V or low voltage down to 0.225V. Safety limits ensure that no excessive voltage will be used in situations where it may be hazardous, and interlocks allow you to incorporate safety barriers.

Looking at the specification, Haji could see that the Model 2115, out of the box, could do 90% of what he needed. And because of its flexible, expandable design, he realized that he could easily modify the system to cover the rest of the requirements.

One thing Haji didn’t know was that KLM's ECUs had already been tested with DIT-MCO systems. "FADEC International use DIT-MCO equipment to test the wiring of their newly-built ECU boxes," says DIT-MCO’s European Manager, Craig Edgar.

Few Serious Competitors

Having found the system he needed, Haji went looking for competitive sources. “I said, okay, what other companies are doing the same as DIT-MCO?  And I found a lot of systems similar to what DIT-MCO provides. But none were exactly the same. I could only find one other company who could provide the same capability.”

Haji put out a request for proposal to the two vendors. Both were able to meet his requirements. Both had excellent reputations for reliability and service. Ultimately, the decision came down economics: DIT-MCO simply offered the better deal.

"At the end, the difference in price was too great," Haji says. "And with DIT-MCO, the training was included. With the other manufacturer, it was an additional cost."

Implementation Problems were "No Problem"

As soon as his Model 2115 was delivered, Haji was ready to begin modifications. All the additional equipment he needed was already in house. "You can add external resources to the system, and get measurements from outside,” says Haji. "I only had to do that with one high-voltage power supply. I just had to connect it with the GPI Bus."

Haji says the system is very easy to use. His training – which he described as very straightforward – only took 3 days. Still, some problems were encountered.

Haji soon realized he needed to change his specification. "I saw something in the specs about relay testing, and discovered it was not possible with the system as it was.  One of the parts, a relay matrix, had to be replaced with another type of switching – LM switching. And to power those relays, an additional power supply was needed." Fortunately, says Haji, DIT-MCO supplies all those things as modular components. They were able to make the necessary changes quickly and easily.

Haji also had some difficulty setting up communication with the external power supply for his high-voltage testing. So he called on DIT-MCO for help.

"Zafar had some problems with the test programming software. He called us up. And we modified the software for him in a matter of days," said Edgar.

"DIT-MCO were very helpful every time I gave them a ring or emailed," adds Haji. "I didn’t have the feeling they were 10,000 miles away."

A New Capability – A New Stream of Revenue

Haji likes the Model 2115's intuitive programming interface. And he really appreciates how the system is built to automatically set up and run tests, and protect against overvoltages.

"Because it is designed for high voltage, continuity testing and things like that, you don't have to do a lot of additional programming yourself," he says.

The main benefit for AFI KLM E&M is that they have a new, valuable capability. They can now perform a full overhaul on their B737 ECUs very quickly, and at a significant savings over outsourcing. They also have an additional service they can offer customers.

"Why buy something more expensive?"

In the end, AFI KLM E&M saved a bundle by purchasing the DIT-MCO Model 2115. And not just compared to outsourcing or the competitor's price.

DIT-MCO International makes a wide range of circuit testers. And some of them include the high-voltage capacity Haji added to his Model 2115. But Haji says those systems also provide many capabilities he didn't need. "For my purposes, I could do everything I need with the Model 2115," he says. "Why buy something more expensive?"

About DIT-MCO

DIT-MCO International, the first name in wire harness testing equipment, has over 60 years experience manufacturing and supporting automatic test systems. To learn more about their complete line of test systems visit their website at www.ditmco.com.

To request an information package with detailed specifications of all of DIT-MCO systems, software,  modular components and instrumentation – or to talk with an engineer about your testing needs – call DIT-MCO at +1 (816) 444-9700. Or visit their website to find a DIT-MCO representative near you.

For cable testing, harness testing and other automated product testing solutions, customers rely on DIT-MCO wiring analyzers.

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