An interesting event happened to a friend of mine in a CJ1+ recently. He has kindly agreed to share his experience with other CJ pilots. This is his report:
I was doing a Jersey to Murcia flight. About half way through the two hours flight time, I became aware of an intermittent humming resonance. To start with I wasn’t sure if I was just imagining it, plus we had kids in the back with their I-pods on full blast ! There were no abnormal indications and I certainly couldn’t pin-point where it was coming from, even when I asked everyone to switch off their music.
A few minutes further along, the master caution light and left generator warning annunciator came on. I followed the emergency checklist. The generator re-set and the voltage was normal, so I switched the generator back on. I wasn’t thinking of diverting, just sorting out the problem once we were on the ground in Murcia. But the resonance didn’t go away and after about ten minutes the generator failed again. I don’t remember what the voltage showed on re-setting this time, but it wasn’t normal ( zero ? ) so the generator stayed off. The electrical load was nowhere near the limits so I didn’t switch anything off.
It must have been only minutes after this second failure that I knew that the resonance was getting worse. We were coming up to Valencia, not far from TOD, but common sense told me not to carry on but get the aircraft on the ground. I plumped for a diversion into Alicante for both good and bad reasons. Valencia would have meant a steep descent or simply an extended routeing to lose height ( FL370 ), whilst Alicante would give us a near normal descent profile, get everyone within a reasonable distance of their destination, and give me the best chance of getting home ! In fairness, it also wasn’t going to involve rushed re-planning for the diversion. As it happened, the noise all but disappeared with descent power.
In the end the aircraft was grounded in Alicante for about four or five days. Luckily the damage was limited to the generator bearings, so we were up and running after fitting a new generator and doing some ground runs.
Sounds like he handled it pretty well!
This may not have anything to do with your problem, but I thought you may find it interesting anyway.
Eck