
User avatar
By alexbrett2
Having only recently got the aircraft back from its annual, and only having done a few short flights squeezed in around work, I decided yesterday to do a dusk trip from Cambridge to Gloucester and back as the weather had turned out OK.

The way out was uneventful (and indeed I can recommend the burgers at the Aviator - very nice!). The journey back had started fine, other than a bit of concern about some traffic that crossed ahead of me, as it's always difficult to judge distances at night (kept a careful watch on it - I presume as it proceeded to orbit around a town at what appeared to be fairly low level that it was a police helicopter or similar in the end).

That was until all of a sudden the low voltage light came on - look at the load meter (which shows load on the alternator) and indeed it's showing 0. First thought is don't panic, remember priority #1 is fly the aircraft, so I turned the autopilot off (don't want it doing anything erratic if the voltage drops) and ensured I was stable on heading and altitude etc.

Next thought is perhaps it's a temporary issue - switch off the avionics, and the master, wait 10 seconds (reading the flight manual later I gather I should probably have waited a minute) and turn back on - still getting low voltage light and no load shown.

Check circuit breakers, all in.

So, assess the situation - navigation is not a big problem (current heading will take me straight to Cambridge, and I had SD running on an iPad etc), so concerns are lighting and communication. I decided therefore to run:
- COM2 (COM1 is a GNS430 so the screen likely means higher draw)
- Nav lights
- Very minimal instrument lighting

Also get handheld transceiver out the bag, and ensure it works and is tuned to the Cambridge frequency so it's ready if needed if the situation gets worse.

I'd not been talking to anybody at this point - I'm about 5 minutes from range of Cambridge so I waited to talk straight to them. I decided not to declare a PAN PAN (though probably should have done in retrospect), but did inform them I'd had an alternator failure, and while I had a handheld onboard there was a risk of communications failure.

Next issue was I realised I couldn't see any town lights any more - a solid cloud layer had appeared beneath me - without my avionics this would make an instrument approach 'interesting' to say the least. As such I decided (based on the weather forecast I'd seen beforehand) to descend to MSA and see if that pops me through it, which fortunately it (just) did.

As I closed in on Cambridge it occurred to me that I might have an issue lowering the gear, as the hydraulic pump is electrically powered, so I quickly reminded myself on the emergency procedure in case that was needed.

At 5 miles I lowered the gear (which fortunately came down fine and gave me 3 greens), reported to Cambridge who cleared me to land at that stage. I decided against using landing lights, as I'd rather do the landing without them than have them fail at a critical moment, and as it was the landing was fine.

After parking up I checked for any obvious problems (e.g. belt snapped or anything like that), but nothing clear - will have to get the engineers to take a look on Monday (though Murphy's law says it'll all work fine)...

Thinking it through afterwards, learning points are:
- I should probably have got the checklist out rather than doing everything from memory
- It wouldn't have hurt to declare a PAN PAN, not really sure why I didn't
- In this case handheld was in my flight bag on the passenger seat, if it had been on the back seat that would have been more complicated - should probably put it in the seat pocket beforehand
User avatar
By Charles Hunt
I don't fly at night, but I reckon you did all you could from memory, better to fly the aircraft than have your head inside the cockpit searching check lists. And yes, call a PAN on the first call.

(As an aside, from Tokyo Year Zero, by David Price, I learn that pan-pan is a post WW2 Japanese, er, 'lady of the night'.)
User avatar
By Flyin'Dutch'
All's well that ends well.

Not sure that I would have volunteered to go into IMC with a duff alternator, or used precious juice on getting the gear down.
User avatar
By Rich T
FD, are you suggesting that you would have landed wheels-up?

When I had my alternator failure (day, but in London TMA) the one thing I question myself over is whether I should have got the gear down while there was still some juice left. In the end when I arrived back at Gloucester I needed to use the emergency gear drop as there were insufficient volts left.

On that occasion I did call a PAN PAN, mainly because I was trying to get a word in on the radio before it died, and someone was on frequency giving their inside leg measurement. As it happened the radio finally flickered off just as I was vacating the runway...

Well done for using COM2 to reduce draw - how did you turn off the 430? On my a/c it would have involved pulling a CB, which I didn't do but since then I have studied the correct one to pull!
User avatar
By adhawkins

On the 430 I fly with, rotating the COM volume knob all the way anticlockwise produces a click, which powers down the display on the 430 after a delay of 5 or 10 seconds or so...

User avatar
By Flyin'Dutch'
Rich T wrote:FD, are you suggesting that you would have landed wheels-up?

Not at all.

But I would not use any of the battery power for getting the gear down as any battery power is more use for comms/nav/approach aid use/pitot heat.

The gear can be sorted out with the emergency extension mechanism if push comes to shove.

The OP stated that he was going through some cloud on the way down.

Although you usually have a fair idea where the cloud should finish, until you're out you don't know for sure.
User avatar
By alexbrett2
To answer a few Qs:
- I turned the 430 off by just turning the volume knob all the way down until it clicked off, I believe that's standard on a 430.
- I was confident in entering the cloud on the way down as my AI is vacuum driven (so thus unaffected even if the battery died entirely) - had I not popped out I'd have climbed back up (the moon was such I could see it was a fairly flat base all around etc), and diverted somewhere that could give me a primary radar SRA (using handheld if necessary). Obviously pitot icing could be a serious issue in that case, so might have to just fly attitude and power etc.
- I dropped the gear only after I was below the cloud base, with the airfield in sight (and cloud base significantly above circuit height etc) - as such no need for pitot heat any more, and should I lose comms I could have gone to the handheld. I have done an emergency extension before, and so that was always an option if needs be, but I decided to try a powered one first.

Also if anybody was interested - the failure turned out to be a tag on a resistor in the wiring to the field connection had snapped, thus nothing was exciting the alternator in to producing power...
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