keep it simple
By Rob Louviaux
It's a good start on number one. Nowhere near the hot temp limit, fuel and oil pressures stabilized in the green, oil temp just where it should be. Now for a cross-generator start to get number two going. Number one engine GEN switch to On and...uh oh, the dang GEN light on the annunicator panel is still on. A check of the voltmeter confirms the bad news: the generator is not generating the expected electricity.
Try resetting. Fortunately, that works. The annunciator light extinguishes, the needle on the voltmeter jumps. We have power. Great, now to get number two started. Huh? The GEN light is back on. The number-one generator has dropped offline.
Let's try another reset. This time, however, it's no go. Nothing works. No number one generator. Nothing to do now but shut down and call the shop.
A generator that fails to come online or is intermittent obviously warrants an investigation, but the fix may not necessarily involve replacing the reluctant unit. Some informed troubleshooting may point to a far less expensive remedy.
When diagnosing problems, even those head-scratching electrical gremlins, it's best to keep it simple. In the case of a problematic starter-generator, start with the basics. Check the wiring all along the circuit, and be especially suspicious of connections�places where wires are fastened to terminals, connections between two wires, and grounds. If one or more just do not look healthy, if wires are frayed or connectors are damaged, worn, or corroded, you may have identified the culprit.
It's not unusual for generator faults to be corrected by repairing something as simple as a crimp-on terminal connector. And why not? Considering the tough working conditions�hot and cold temperature and high and low pressure extremes, vibration, and age�it's understandable that a crimped connector, or any type of connection in the circuitry, could work loose, corrode, or simply wear to the point of failure.
Remember, when troubleshooting your electrical system, or any system on the airplane, keep it simple and start with the basics.
Rob Louviaux is Aircraft Maintenance Manager at Executive Aircraft Services, an authorized Twin Commander Service Center at Scottsdale Airport (KSDL).
Discuss this article in the forums...
