Electrical Failure and Backup GPS

Discussion in 'Lessons Learned' started by Palmpilot, Jan 12, 2018 at 12:23 PM.

  1. Palmpilot

    Palmpilot Touchdown! Greaser! PoA Supporter

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    I had an interesting experience yesterday. While flying a rented Cessna 182S around the SFO area on a recreational flight, my pilot-rated passenger pointed out that the "volts" annunciator had come on. The ammeter was showing a small discharge, and RPM was in the green, so it was apparent that the alternator had gone offline. I turned off both of the avionics masters and cycled the master switch, but each time I did the latter, the annunciator came back on after a few seconds, so it was evident that we needed to terminate the flight.

    I then turned on only one avionics bus in order to conserve battery power. Unfortunately, the GPS and the moving map display are on separate buses, so that meant that we no longer had usable moving map information. That, together with the fact that the plane has no DME, complicated the task of avoiding an airspace bust. Further complicating the problem was that the weather was MVFR in the part of the area where the failure occurred, so it was difficult to identify enough visual landmarks to be sure of our position relative to the nearby charlie and bravo airspace. I got out my portable GPS, but it took much longer than normal to acquire the satellites, which was quite frustrating! Eventually it did come up, and fortunately it confirmed that we were still outside of the bravo and charlie, and we were able to remain so until we landed.

    After the flight, it occurred to me that if I had turned on my iPad, it probably would have acquired our position more quickly than my handheld GPS did. In the future, whenever I am flying in complex airspace, I think I will keep a backup GPS position source turned on from the start of the flight, especially when the weather is marginal. That would greatly reduce the workload in case of an avionics problem.

    Another thing I could have done better was to turn off the alternator side of the master switch once it became clear that the alternator wasn't coming back on line. That would presumably have further reduced the load on the battery.
     
    Last edited: Jan 12, 2018 at 12:44 PM
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  2. Lachlan

    Lachlan Cleared for Takeoff

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    Sounds like you handled it well. With the availability of so many great backup options these days, I think your future plan is but only sound, but very common.
     
  3. idahoflier

    idahoflier Pre-Flight

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    Good learning. Not trying to be critical, but did you contact NORCAL to advise them of the situation? Perhaps they would have given you a clearance to operate in the airspace while you got things sorted out?
     
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  4. Radar Contact

    Radar Contact Line Up and Wait

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    Didn't I already post a resolution to losing all electrical navigation on a plane??:)
     
  5. Palmpilot

    Palmpilot Touchdown! Greaser! PoA Supporter

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    I didn't, although I did look up and dial in the frequencies in case I needed them.

    A class C transition would certainly have been a possibility, but when the portable GPS finally acquired the satellites, it became clear that we were in a position where it would not be needed.
     
  6. Palmpilot

    Palmpilot Touchdown! Greaser! PoA Supporter

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    I don't remember. Which thread was that in?
     
  7. Radar Contact

    Radar Contact Line Up and Wait

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  8. DesertNomad

    DesertNomad Cleared for Takeoff

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    I'm surprised you weren't already talking to Norcal. Here in Reno everyone automatically gets flight following and even when they sign off as I am heading out to wander around, I still monitor their frequency.
     
  9. Palmpilot

    Palmpilot Touchdown! Greaser! PoA Supporter

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    I was talking to them for most of the flight up to that point, but they dropped us when we left the previous sector.
     
  10. Stewartb

    Stewartb En-Route

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    I had an intermittent alternator for several years. My battery is a small Odyssey on the firewall. In the alternator failure times I turned off lights, particularly the rotating beacon I had at that time, and with that my avionics master could stay on for the duration of my flights without any issue. Even then I’d usually have adequate battery power to start the plane when it was time to come home. Radios and gps have tiny power consumption. Turn off the energy consumers and get on with the flight. That said? I have a GDL39-3D so my iPhone and Garmin Pilt are always available as a backup. I never “needed”it for that.
     
  11. Palmpilot

    Palmpilot Touchdown! Greaser! PoA Supporter

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    Considering how close to home we were, in retrospect I was probably more concerned about battery endurance than I needed to be. The discharge showing on the ammeter was not large.

    By the way, I checked the club's Web site, and they replaced the alternator belt the day after my flight, and the plane has apparently been flown several times since then.
     
  12. Larry in TN

    Larry in TN Line Up and Wait

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    What does the C-182 AFM say to do in the event of an alternator failure?
     
  13. steingar

    steingar Touchdown! Greaser!

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    Another in a long list of reasons not to go glass. Not that I had any bleeding choice in it.
     
  14. Palmpilot

    Palmpilot Touchdown! Greaser! PoA Supporter

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    I think glass panels have an internal backup battery.
     
  15. Palmpilot

    Palmpilot Touchdown! Greaser! PoA Supporter

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    See attachments.
     

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  16. Tantalum

    Tantalum Cleared for Takeoff

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    Good call, I'll make note of that too for reference

    I generally just always keep the iPad with Foreflight on, I can get a solid 3 hrs battery out of it and with a little battery booster I can about double that

    **Incidentally, this is another +1 for Cirrus, having the belt and gear driven alternators and separate buses really take a lot of the stress off of the electrical failure scenario
     
  17. steingar

    steingar Touchdown! Greaser!

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    Color me stupid today (not that it isn't a change from any other day). If there is a handy internal backup battery why was the OP in dutch when his alternator took a dump?
     
    Last edited: Jan 16, 2018 at 12:34 PM
  18. Larry in TN

    Larry in TN Line Up and Wait

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    Just follow the applicable procedure in the AFM and you will be covered. That step is in the procedure.
     
  19. Palmpilot

    Palmpilot Touchdown! Greaser! PoA Supporter

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    It's on the checklist, if only I had thought to get it out after I finished doing it from memory. :redface:

    Another item, which is in the expanded procedures section but not on the checklist, is to check the alternator field breaker.
     
  20. Tantalum

    Tantalum Cleared for Takeoff

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    This actually brings up a good point. I know a lot of club rentals have a home-made laminated checklist that they keep in the plane.. some of these are better than others. I've seen some that are woefully short on items, and others that are just illogical in their ordering with no sense of a typical flow. Throughout training it's habit to use this one.. it is part of the aircraft preflight to check for the POH in the plane, and usually there's some crumpled up water logged falling apart book jammed in a seatback pocket somewhere, so I wonder when faced with an actual emergency how many typical club renters would go to the manual and find the correct procedure, vs just consulting the home made sheet which may not always be totally accurate, or going off memory items

    I wouldn't feel bad about not checking that. Someone told me once not to reset this, the logic being that there is a reason it tripped, so don't reset it and risk a fire or making the short worse and effecting other instruments on the same bus, etc.. It's helpful for troublshooting, but I've had two different CFIs tell me to not bother resetting circuit breakers until you are on the ground

    PS many instructors see the batt/alt field as "one" button in their training so as to discourage people from starting on just batt and forgetting to flip on the alternator as well. So I can totally understand why it would feel natural to flick them both off, vs just the alt. And sorry for the Cirrus fanboy stuff but that's another logical thing with them is having bat 2, bat 1, and the alternators naturally flow left to right on the switches as you power up the plane
     
  21. Larry in TN

    Larry in TN Line Up and Wait

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    I would follow the recommendations in the airplane's AFM over any generic recommendations.
     
  22. Tantalum

    Tantalum Cleared for Takeoff

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    If a CB is popping and I'm in the air I'm not going to reset it. There's a reason it popped and resetting it won't fix whatever caused it to pop. I've only ever reset CBs on the ground

    I generally am a big proponent of checklists, they're literal life savers, especially in getting the plane setup for IFR flight with radios, etc., but I also like to know the logic behind why a checklist item exists and the implications of each action, understanding why it is telling me to do what it is. If I go to turn the landing light on and the CB pops, I'm leaving it popped. If I turn the AP on and the CB pops, I'll leave it alone. there's a load somewhere tripping it..

    To each their own, but that's one area where I feel like I would take some "pilot's discretion" in waiting to reset. If the plane is in controlled flight then resetting the CB can't really help me at all at that point, other than possible causing a fire or resulting in some other failures, etc..

    But that's just me
     
  23. Checkout_my_Six

    Checkout_my_Six Final Approach

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    Cept I’ve had breakers pop for the wrong reason. An arcing wire near by on a bus bar making heat. Bus bar power had a bad connecter and was heating up. Near by breakers were trippin from that heat. It was a bit puzzling till I saw what was going on with the burned wiring.
     
  24. Tantalum

    Tantalum Cleared for Takeoff

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    Yeah.. that's why I'm not resetting it. To me resetting a CB in the air without knowing what caused it to pop is like remotely silencing a burglar alarm without checking to see if your house has any intruders. There's a reason it popped..
     
  25. Stewartb

    Stewartb En-Route

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    If there's a good reason why it popped? It'll
    pop again.
     
  26. kyleb

    kyleb En-Route

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    Glass is no panacea. It brings its own failure modes and guaranteed planned obsolescence. But electrical considerations shouldn't be a primary driver for the decision.

    Properly designed, installed, and maintained, an electrical system should be far more reliable than the legacy vacuum pump/mechanical gyro combination. I know I've never had an electrical failure in a car or airplane (and I have tens of thousands of hours between the two), but had a couple of vacuum pumps and gyros go tango uniform back in the day, in <500 hours flying with a vacuum system.

    Beyond that, a backup battery and/or load shedding should resolve the .1% case.
     
  27. Larry in TN

    Larry in TN Line Up and Wait

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    The AFM procedures will take into account the system design and specific components installed. Not all CBs are the same. Different electrical systems are designed differently. The recommended procedure for one system or component will not necessarily be applicable to a different system or component. The AFM is the proper place for determining the correct procedure for a particular airplane.
     
  28. Checkout_my_Six

    Checkout_my_Six Final Approach

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    in my case the popped breaker had nothing to do with the cause. The landing gear indicating circuit, a 1 amp light circuit, was popping....when the bus voltage supply from the alt had a bad connector. So, there was nothing I could do. It had to be glowing red...cause I could feel the heat above my legs. That wire is hard fused at 80 amps....

    Bottom line.....heat causes resetable circuit breakers to pop. We assume current flowing thru the breaker is causing the event. It may not.
     
    Last edited: Jan 16, 2018 at 4:49 PM
  29. Palmpilot

    Palmpilot Touchdown! Greaser! PoA Supporter

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    It seems rather non-optimal, though, that it's not on the checklist.
     
  30. Palmpilot

    Palmpilot Touchdown! Greaser! PoA Supporter

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    I don't think I would have been "in dutch" unless I violated somebody's airspace. In any case, I wasn't flying a glass panel airplane. The 182S is the last of the round dial Skylanes.
     
  31. Tantalum

    Tantalum Cleared for Takeoff

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    Generally true, yes. But I think some discretion is also needed in understanding what goes into the checklists and why they're written the way they are and what goes behind it, both logically and mechanically. I flew with someone recently who forgot to switch tanks after initial startup.. was very checklist obedient but just didn't switch (I was safety pilot). We taxied to the runup area, did the runup, everything, and as we're cleared for take off goes "oh, I forgot to switch tanks, let me do that now" (as we're rolling onto the runway) and I said helllll no, leave it on Right and we'll switch from the air later. We switched once we were at 4K and were well within gliding range of at least one airport and several suitable fields.

    I bet you there's a reason it is not on the main checklist though..
     
  32. Larry in TN

    Larry in TN Line Up and Wait

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    Those who wrote the checklists and procedures in the AFM should have a much better understanding of the specifics of the airplane and system operation in abnormal situations than would those who fly it. I don't think outguessing them with generic rules-of-thumb is a good idea.

    Many GA instructors do not emphasize using the AFM for abnormal situations. I think that's a bad practice. The AFM procedures and checklists are there for a reason. When something goes wrong we should be thinking of references the AFM procedures instead of doing everything from memory. The AFM will specify what actions should be done from memory but, even those, should be backed up with the AFM checklist if time permits.

    I don't understand your example. It seems to be of a pilot who failed to follow the checklist procedure. I am advocating using the checklist.
     
  33. Tantalum

    Tantalum Cleared for Takeoff

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    And I am not advocating not using it. People make mistakes, often, and the checklist is there to help you. There was just a guy the other day who didn't do his pretakeoff IFR checklist right (GPSPSHAR) and nearly wrecked his plane fumbling with the xpndr on the takeoff run

    But the number one rule always, even before the checklist, is "fly the plane" and sometime you have to use your best judgment given the situation you are in. I've known two different people who had smoke in the cockpit following electrical anomalies, so I'm sorry but I'm not resetting CBs in flight if they pop. Blindly following procedures without situational awareness is no safer than not using checklists in my book

    Remember Air Transat? These guys literally dumped their fuel out of the plane by pumping fuel from a good wing tank into the one with the leak.. they "At 05:36 UTC, the pilots received a warning of fuel imbalance. They followed a standard procedure to remedy the imbalance by transferring fuel from the left wing tank to the near-empty right wing tank." <- they should have instead wondered why there was a fuel imbalance to begin with before remedying it. If you are burning similar lbs/hr there is no reason you should have a severe imbalance

    So I agree with you. Follow the checklists.. but when the sh*!t hits the fan I think it pays to make an assessment of the situation to find the most pragmatic action.
     
  34. Larry in TN

    Larry in TN Line Up and Wait

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    Unwarranted extrapolation.
     
  35. Palmpilot

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