Handling intermittent faults in Rockwell Collins glass MFD on piston twins

HANDLING INTERMITTENT FAULTS IN ROCKWELL COLLINS MFD

Handling intermittent faults in a Rockwell Collins glass Multi-Function Display (MFD) on a piston twin requires a systematic and professional diagnostic approach. Intermittent faults are among the most challenging to diagnose because the problem is not constant. It may appear and disappear seemingly at random, making it difficult to pinpoint the root cause. This article outlines the key strategies and professional practices for addressing these elusive issues.

COMMON CAUSES OF INTERMITTENT FAULTS

Intermittent faults in a Rockwell Collins MFD, such as the Pro Line 21 system, are rarely caused by the display unit itself. More often, the problem lies in the system’s power supply, wiring harness, or communication network. Common culprits include:

  • Loose Connections 🔌: A loose pin in a connector or a poorly secured wire can cause an intermittent connection, which will manifest as a flickering screen or a momentary loss of data.
  • Electrical Noise âš¡: Spikes or fluctuations in the aircraft’s electrical system can disrupt the sensitive electronics in the avionics. This can be caused by a failing alternator, a bad voltage regulator, or a component drawing an excessive amount of power.
  • Chafed Wiring 🪢: Over time, wires can rub against a metal part of the airframe, causing the insulation to wear down. This can lead to intermittent shorts or grounding issues.
  • Corrosion 🦠: Corrosion on a connector pin or a ground point can create a high-resistance connection, causing a voltage drop that disrupts the system’s operation.

THE DIAGNOSTIC AND REPAIR PROCESS

The principle of authority is paramount when diagnosing and repairing these faults. All work must be performed by a certified avionics technician who is trained and authorized to work on Rockwell Collins systems and the aircraft’s specific wiring.

  1. Detailed Debrief: The first step is to get a detailed debrief from the pilot. When did the fault occur? Was it at a specific engine RPM, during a particular phase of flight, or when a certain electrical component was turned on? This information provides crucial clues that can help narrow down the search.
  2. System Log Retrieval: The Rockwell Collins system, like most modern avionics, has a built-in diagnostic log. A technician will use a laptop with specialized software to connect to the avionics bus and retrieve these logs. The logs often contain error codes and a timestamp of the event, which can be invaluable in correlating the fault with a specific moment in time.
  3. Visual and Physical Inspection: A thorough physical inspection of the avionics bay, wiring harnesses, and connectors is crucial. The technician will look for signs of chafing, corrosion, or loose connections. They will also perform a “wiggle test” on connectors and wiring to see if they can replicate the intermittent fault.
  4. Electrical Checks: Using a high-quality multimeter, the technician will perform a series of electrical checks to verify the integrity of the system. This includes checking for stable voltage at the display’s power connections, performing continuity checks on the wiring, and verifying all ground connections are clean and secure.

OUR EXPERT APPROACH

We have built our reputation on a foundation of social proof—a long history of satisfied customers across California, Arizona, and Nevada who trust us with their piston twins. Our commitment to consistency in our diagnostic and repair process ensures that we accurately identify the root cause of the intermittent fault, rather than simply addressing the symptom. Our unique selling proposition is being the only 24/7 maintenance center in the area. When a critical MFD issue grounds your aircraft, our round-the-clock availability means we can begin the diagnostic and repair process immediately, minimizing your aircraft’s downtime and getting you back in the air with confidence.

FOOTNOTES

  1. Rockwell Collins. “Pro Line 21â„¢ Reference Guide.” https://www.rockwellcollins.com/-/media/files/services/training/courseware/pro_line_21_ref_guide.pdf
  2. Director of Maintenance Magazine. “Troubleshooting Intermittent Avionics Problems.” https://www.dommagazine.com/dom-articles/troubleshooting-intermittent-avionics-problems
  3. Aviation Consumer Magazine. “Wiring Woes.” https://www.aviationconsumer.com/maintenance/wiring-woes/
  4. Aircraft Electronics Association. “Avionics Maintenance Best Practices.” https://www.aea.net/resources/bestpractices

The Aero Center is located at William J. Fox Airfield KWJF | Lancaster, CA. Contact us at 209.885.6950 for questions or appointments.

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