Repairing intermittent engine temperature readings on an Avidyne glass cockpit typically involves troubleshooting the engine sensor, its wiring connections, and the Avidyne Engine Interface Unit. A fluctuating reading is a significant concern, as it can make it difficult to monitor critical engine health parameters like Cylinder Head Temperature (CHT) and Exhaust Gas Temperature (EGT). A methodical approach is required to pinpoint the exact cause, which is often a faulty physical component rather than a software issue.
Diagnosing the Problem
An erratic engine temperature reading can be caused by a variety of issues, from a simple loose connection to a failing sensor. A professional technician will use a systematic approach to diagnose the problem.
- Sensor Failure: The most common cause is a faulty sensor. CHT and EGT probes are thermocouples that can degrade over time due to high temperatures and vibration. A failing thermocouple will often send an unstable signal, resulting in an intermittent or erratic reading on the Avidyne display. A technician can use a multimeter to check the resistance of the sensor and compare it to the manufacturer’s specifications.
- Wiring and Grounding Issues: The wiring that connects the sensor to the Avidyne system is susceptible to wear and tear. A loose or corroded wire, a faulty terminal, or a poor ground connection can cause an intermittent signal. Vibration in a piston aircraft can cause these connections to loosen over time. A technician will perform a thorough visual inspection of the wiring harness and check for continuity and voltage drop.
- Avidyne Engine Interface Unit: The Engine Interface Unit (EIU) is the component that receives the analog signals from the engine sensors and converts them into a digital format for the Avidyne display. While less common, a fault in this unit’s internal circuitry can cause it to misinterpret a clean signal, leading to an erratic reading. A technician can use Avidyne’s diagnostic tools to check for fault codes and monitor the raw data coming from the EIU.
The Professional Repair Process
For complex avionics issues, a professional avionics technician is required to perform the repair.
- Component Testing: The technician will first test the sensor to confirm it is working correctly. If the sensor is found to be faulty, it will be replaced with an FAA-approved part. This is the most common and straightforward fix.
- Wiring Repair: If the wiring is at fault, the technician will repair or replace the damaged sections. All connections will be cleaned, tightened, and secured to prevent future issues caused by vibration.
- System Diagnosis: If both the sensor and the wiring are found to be in good condition, the EIU will be the next component to be diagnosed. If a fault is found, the EIU will be repaired or replaced by an authorized service center.
The Aero Center Advantage
At The Aero Center, we specialize in the maintenance of single-engine and twin-piston aircraft. Our technicians are factory-trained and have the authority and expertise to work on Avidyne glass cockpit systems. We understand that an erratic engine reading is a major safety concern, and our commitment to consistency and quality has built our reputation as a trusted provider of avionics maintenance in California, Arizona, and Nevada.
We are the only 24/7 maintenance center in the region, a unique selling proposition that allows us to drastically reduce aircraft downtime. Our priority is to provide a fast, professional, and lasting solution so you can fly with confidence. Our track record of successfully resolving these complex avionics issues provides the social proof you need to trust us with your aircraft’s most critical systems.
Footnotes:
- https://www.avidyne.com/
- https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak/media/19_phak_ch17.pdf
- https://www.aopa.org/news-and-media/all-news/2012/october/1/avionics-g1000-updates
- https://www.lycoming.com/sites/default/files/SI1384B.pdf
The Aero Center is located at William J. Fox Airfield KWJF | Lancaster, CA. Contact us at 209.885.6950 for questions or appointments.