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Alternator Failure

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Sep 4, 2010
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Learning from the experience of others... had my first alternator failure today (broken belt).

Waited two hours at Catalina (KAVX) for the fog to clear, finally taking off at 10:00pm. Direct flight to Carlsbad (KCRQ), expecting the ILS approach as ATIS reported 400 ft overcast. I am instrument rated. About 1/3 way across the water (4500ft, above the clouds in VFR conditions), warning light illuminated, indicating low voltage. MFD indicates 4A alternator, -32V bus voltage. In the several minutes it takes me to confirm this is indeed not a false alarm, I am probably now 1/2 way across the water with a cloud layer below. Best not to return to Catalina as it is a somewhat challenging approach and a short runway. As I am then attempting to explain to my wife (in the co-pilot seat) how to pull the fuses on the PFD & MFD displays, too late, displays start flickering. Battery is dead.

What I did right:

1. Flew the plane, used the backup instrumentation.
2. Was monitoring Socal in preparation to request IFR approach. I notified them of my situation, did not declare an emergency. They assigned me a squack code, gave me heading direct to the nearest airport in reporting VFR weather (KRNM), cleared me down to 4000ft.
3. I carry a backup battery-powered radio. It connects to my headset and to a special jack I installed in my plane the routs the radio antenna to an external VHF antenna. I have tested this several times in the past, it did not let me down.
4. I have mounted on my control wheel a backup GPS unit that I am familiar with. Quickly configured for direct to KRNM, gave me heading & distance.
5. Once I had KRNM in sight, reported this to socal, and switched to KRNM tower, who cleared me for immediate landing.
6. Per the checklist, slowed the plane down to 90kts, and manually deployed the landing gears.
7, Requested and was granted an low pass of the runway so that someone in tower could confirm my gears were down and locked.
8. Landed the plane.
9. Almost forgot, had plenty of extra fuel.

What I did wrong:
1. Upon receiving the first warning that there was a potential problem with the alternator, I should have immediately turned off all non-essential equipment. That would be just about everything except for one Garmin 430. This would have greatly extended the primary radio life.

2. Should have slowed the plane down and lowered my land gear and flaps (to 10 or maybe 25 deg) while the hydraulics and confirmation lights were still working. Could have just flown at 120kts the rest of the way.

3. Was not familiar enough with the powering down of non-essential equipment. This needs to be practiced.

All I can say is that some of my training paid off today, plus having the right backup equipment.

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