Fixing intermittent GPS signal loss on an Avidyne glass cockpit in a piston twin requires a systematic diagnostic approach to pinpoint the root cause, which is rarely the display unit itself. These issues are most often caused by a problem with the GPS antenna, the coaxial cable connecting it to the receiver, or a fault in the power and ground wiring.
Common Causes of Intermittent GPS Signal Loss
- Antenna Issues 📡: The GPS antenna is a critical component. A faulty antenna, a loose connection, or a worn-out base can cause the signal to drop intermittently.
- Coaxial Cable and Connector Problems 🔌: The coaxial cable that runs from the antenna to the GPS receiver is susceptible to damage. Chafing, corrosion on the connectors, or a loose BNC fitting can disrupt the signal.
- Electrical Interference ⚡: Other electrical components, such as a magnetron in the weather radar or a failing alternator, can introduce electrical noise that interferes with the weak GPS signal.
- GPS Receiver Faults 💻: The GPS receiver, which is typically a remote-mounted unit, can have internal issues that cause it to lose its signal.
- Outdated Software or Databases 💾: While less common for intermittent signal loss, an outdated software version or a corrupted navigation database can sometimes cause system communication errors that are mistaken for a GPS signal issue.
Diagnostic and Repair Workflow
The principle of authority is paramount; all work must be performed by a certified avionics technician trained and authorized to work on Avidyne systems.
- Pilot Debrief and System Log Retrieval 🗣️: The technician will begin by getting a detailed account from the pilot. Did the signal loss occur in a specific phase of flight? Was it near a specific airport or in a particular location? They will then connect to the avionics bus to retrieve the internal logs, which record fault codes and can often point directly to a GPS receiver error.
- Physical Inspection 🧐: A thorough physical inspection of the GPS antenna and the coaxial cable is crucial. The technician will check the antenna for any signs of damage or loose mounting hardware. They will trace the coaxial cable from the antenna to the receiver, looking for chafing, kinks, or damaged connectors.
- Electrical Checks ⚡: Using a multimeter, the technician will check the continuity of the coaxial cable to ensure it’s not broken. They will also use a specialized GPS signal tester to verify the strength of the signal coming from the antenna and the power and ground connections to the receiver.
- Component Replacement 🔄: Once the problem is isolated, the faulty component is replaced. A damaged coaxial cable will be replaced with a new, certified cable. A faulty antenna or GPS receiver will be replaced with a new, factory-authorized part, and the system will be reconfigured and tested according to the Avidyne Installation Manual.
Our commitment to this workflow has built our reputation on social proof from a loyal customer base across California, Arizona, and Nevada. Our unique selling proposition is being the only 24/7 maintenance center in the area. This commitment to consistency means we can begin the diagnostic and repair process immediately, minimizing your aircraft’s downtime and getting you back in the air with confidence.