"Center Mooney 5612Q is declaring an emergency, generator failure and my HSI gyro is slowing"

[DonMuncy]

My (limited) experience is that if no one was affected by your actions, they usually don't bother. If anyone has to divert, hold or take some other action because of ones problem. they will follow up.

[J0nathan225]

Ok. So it gets worse before it gets better I suppose? I get some solid vectors from approach to help me while shooting an LPV approach (can't recall the airport) down to DA, but I don't break out. As I call missed my wife says , "I can see the airport below us!" While climbing out I look down and I too got a glimpse, but I was not in a position to land and the plane was still flying so I chose not to make any abrupt or irrational decisions. I continue my climb out trying to call missed to approach, after some helpful retrans from another aircraft I gain enough altitude to make contact. After 10 mins of approach calling out 2-3 different airports with weather no better than OC at 400' and me turning to 2-3 different airports as they give me new vectors I look over and see that the generator is picking up the 5-10 amp load of my avionics now. I tell approach I need to head east to better weather 1000' or better. This resulted in flying at ~3500' for another 30 mins to start the RNAV approach into KEXX all still IMC. That gave me time flying straight and level to test that my autopilot was still working so I engaged it and took a breather sorta speak to set myself up for the next approach. I got passed off twice to new controller, but they were all very helpful and told me to limit my transmissions along my flight to conserve power. Obviously I broke out and landed without issue, so far the Family owned FBO/Service personnel at KEXX have been very accommodating and helpful. 

I called and let ATC know I was down and safe at KEXX and also submitted a NASA report. On the drive up to Virginia I called AOPA using their legal services to see if there is anything else I need to do. Other than the steps I already took he recommended not moving the aircraft until a mechanic has looked at it and puts something in the log book even if it’s “could not duplicate”.

Today they were able to get to troubleshooting and told me they ran it up a few times and indeed the generator is failing, as they increased RPM the Voltage would drop off. They are working quotes and options for me now, so far from reading on the forum; other than some weight savings I don't see any reason to go the more expensive route and convert to an alternator. They should end up ordering an overhauled generator and installing it, after which I will have them trouble shoot the G2 OAT probe as it showed 110F during landing when the outside temp was ~70F (maybe the failing generator somehow caused this?) and also my HSI Gyro or slave function that seems to lag and give me erroneous readings. (This has been somewhat ongoing, do I opted for the G5?)

Sorry for the long post and poor grammar.

Jon.

[Danb]

Nice explanation and job well done, your safe.

[J0nathan225]

More thoughts, please give opinions:

 I did some power math, I have a 33Amph battery, lets assume non-ideal conditions, say the battery is at maybe 25amps when generator failed. Well after turning off all of what I did, I was using less than 10 amps an hour. So I had over 2.5 hours (check me on this), so knowing what I know now I would have proceeded on my original course and not requested vectors to an approach so close to the mountains, bad weather, and opposite direction of my current flight path. I have drilled into me "30 minutes of power on battery", but as I digest my panel and look up draw rates of what I still had ticking 30 mins is a very large under estimation from my math. 

 

 

[Boilermonkey]

More thoughts, please give opinions:
 I did some power math, I have a 33Amph battery, lets assume non-ideal conditions, say the battery is at maybe 25amps when generator failed. Well after turning off all of what I did, I was using less than 10 amps an hour. So I had over 2.5 hours (check me on this), so knowing what I know now I would have proceeded on my original course and not requested vectors to an approach so close to the mountains, bad weather, and opposite direction of my current flight path. I have drilled into me "30 minutes of power on battery", but as I digest my panel and look up draw rates of what I still had ticking 30 mins is a very large under estimation from my math. 
 
 

Your right, but there are a lot of variables like the peak draw that may happen when you transmit. 1.5 to 2 hours would probably be safe. That being said, what you did was superb. Find the closest suitable airport and get down. Don't take new risks, but get down. If you have to ferry...figure that out in VFR.

Sent from my SM-G960U using Tapatalk

[carusoam]

Watch your units... from beginning to the end... it gets confusing as assumptions will be made...

33 ideal Amp-hours... (temp, battery age, battery condition, etc)

25 amps initial drain rate...

or 25 amp-hrs still stored when conservation began?

10 amps conserving drain rate... real... measured not calculated...?

Depending on how long it took to recognize the issue, then shed the load...

Under perfectly ideal conditions, room temp, new battery, fully charged, immediate recognition, I would expect failure in under 3.3 hours...

draining at 25 amps would ideally leave you with 1.3 hours...

 

How old is your battery, has it been load tested with your eyes observing the test?

Having a single battery...? It isn’t a Gill is it?

alternatives start coming to mind...

I  carried an extra battery and a portable Nav com radio ... And a portable gps with waas vertical Nav... in an M20C while I was VFR only...

IMC is pretty serious business because it can turn into low IMC...  low IMC is extra serious...

What were your options once the electrons had left your ship’s battery?

on the east coast... the training was to fly out over the ocean and descend beneath the clouds slowly... once below the clouds everything was supposed to be VFR and OK... really?

That is not acceptable any more is it?

So many extra power sources, portable Nav and com sources... dozens of AA batteries in every pocket...

Where are you at on these little extra details?

I have two extra large batteries kept in constant conditioning... others add a spare alternator...

As for the Generator vs Alternator discussion... nobody puts new generators in anymore...

The problem with my generator was on cold days... Starting the plane used much of its available charge... the long taxi took up most of what was left...

Departing into IMC on a near dead battery would leave really few options...

Really new Mooneys have moved to having an essential bus... Much easier to shed loads... and still fly the plane... They do this because they don’t want the plane to be the reason a pilot isn’t with us anymore...

I don’t go anywhere without an iPad and iPhone both ready to navigate with current WingX....

If you have kids... spare iPhones collect all over the place...over time.

Thinking inside the box...in a PP fashion only.. not a CFII...

Best regards,

-a-

[jaylw314]

1 hour ago, J0nathan225 said:

More thoughts, please give opinions:

 I did some power math, I have a 33Amph battery, lets assume non-ideal conditions, say the battery is at maybe 25amps when generator failed. Well after turning off all of what I did, I was using less than 10 amps an hour. So I had over 2.5 hours (check me on this), so knowing what I know now I would have proceeded on my original course and not requested vectors to an approach so close to the mountains, bad weather, and opposite direction of my current flight path. I have drilled into me "30 minutes of power on battery", but as I digest my panel and look up draw rates of what I still had ticking 30 mins is a very large under estimation from my math. 

Well, yes, but.......

As your battery ages, the capacity drops.   So it does with cold temps and inadequate electrolyte.  Worse case scenario, you could have a battery that has 25-50% capacity, but it would still work fine starting the motor and you would be none the wiser.  And in the situation you were in, it's not like you'd know how much battery you had left or when it would quit.  So yes, I think "30 minutes on the battery" is a pretty good policy in that situation...

[DonMuncy]

39 minutes ago, jaylw314 said:

Well, yes, but.......

As your battery ages, the capacity drops.   So it does with cold temps and inadequate electrolyte.  Worse case scenario, you could have a battery that has 25-50% capacity, but it would still work fine starting the motor and you would be none the wiser.  And in the situation you were in, it's not like you'd know how much battery you had left or when it would quit.  So yes, I think "30 minutes on the battery" is a pretty good policy in that situation...

Again points out the need for periodic capacity checks of your battery.