The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts.


Cessna Model 210M Centurion
Failed Alternator Cooling Fan

The alternator cooling fan came apart after takeoff, and parts punched a hole in the induction air box downstream of the air filter. Also, the alternator belt became loose in the engine compartment. Loss of power from engine FOD damage resulted in an uneventful landing back to the airport. The cooling fan had fractured at one of the fins’ spot welds.

Part total time: 193.0 hours

Cessna Model U206B
Failed Alternator Brush Holder

During initial climb, crew noticed white smoke coming from the aircraft’s left side, plus a burning smell in the cockpit. The flight returned and landed uneventfully. Upon investigation, the alternator field brush had departed its holder, sending positive voltage out the ground wire, breaking it free of its connector and shorting on the firewall-mounted noise filter. The noise filter and alternator required replacement; the ground wire was repaired.

Part total time: Unknown

Cessna Model 404 Titan
Complete Electrical Failure

The right alternator failed during cruise flight; shortly thereafter the left alternator’s drive clutch failed. The pilot diverted and used the emergency landing gear blowdown system to extend the gear and land safely without additional issues.

The right alternator appeared to have an internal short that generated a power spike to the regulator. The power spike caused both regulators to fail. After thoroughly inspecting associated wiring and replacing the right alternator, the left alternator drive clutch and both voltage regulators, the aircraft was returned to service.

Part total time: 1961 hours

Cirrus Design SR22
Unknown Failures

During acceptance inspection of new alternator, it was noticed that the slip-ring housing was clocked 180 degrees out of alignment out of the box. This plane has had several repaired alternators installed on it. The most recent alternator had only 131.1 hours before it failed and the one previous to that had 67.2 hours on it before it failed.

Part total time: 0.0 hours

Piper PA-31-350 Navajo Chieftain

Loose Drive Belt

While conducting training flights, the crew reported electrical problems. Inspection revealed the batteries were dead. Further investigation found the right alternator drive belt loose and the left alternator unserviceable. The battery and left alternator were replaced. The right alternator drive belt was adjusted and the aircraft was returned to service.

Part total time: Unknown


Please enter your comment!
Please enter your name here