I have questions for emergency situation in IMC.

I was asked about low volt or icing condition IMC from my school's checker.

The checker said "if you see low volt annunciator on PFD how can you deal with this problem under IFR flight?" So I answered "first contact ATC, and request radar vector to nearest airport and then, I will follow the check list for low volt annunciator." However, the checker said this answer was wrong.

Also, I got a similar question from the checker which is icing condition during IFR flight. "When you face on icing condition under IFR flight, how can you deal with this situation?" So I also answered "first, I will turn on pitot heat, deforster and cabin heat, After that, I will do climb or descent to get warm air to rid of icing and try to get VMC condition. However, I will consider the altitude which is be higher than MEA. Also, I will do follow the check list for icing. If the problem is not solved, I will let ATC my problem, and request radar vector to nearest airport." But, the checker thought this answer was wrong too.

Is there any problem from my answers? Or could you let me know how I can deal with this low volt or icing situation in IMC?

Thank you very much!

  • $\begingroup$ What kind of airplane is it? $\endgroup$
    – John K
    Commented Dec 18, 2018 at 14:33
  • $\begingroup$ I edited the title of your question to try to better summarize what you're asking. Do note that IMC and IFR are not the same thing, and IFR does not imply IMC. $\endgroup$
    – user
    Commented Dec 19, 2018 at 13:53
  • 1
    $\begingroup$ Did you ask the checker, or your instructor? Maybe there are some very specific answers that your school is looking for? $\endgroup$
    – Pondlife
    Commented Dec 19, 2018 at 16:09
  • $\begingroup$ my airplane is C172S G1000 $\endgroup$
    – Mun Park
    Commented Dec 19, 2018 at 17:54
  • $\begingroup$ I asked what answer was, but the checker did give it to me. $\endgroup$
    – Mun Park
    Commented Dec 19, 2018 at 17:55

2 Answers 2


Based on a 172S G1000

  • I wouldn't say your answer for the first question is wrong, but your steps are out of order. Before contacting ATC you need to verify the issue via whatever the POH says. On a 172S that means you will cycle the alternator switch and verify low voltage on the G1000 and whether or not the battery is charging. Do realize that the G1000s have a backup battery that provides x amount of backup time and it should have already been tested in the pre-flight and set to arm, if you verify the issue then limiting battery load and contacting ATC would be the next step, never the first, and the value of backup time should be known and planned around(can't recall at this time, sorry).

  • I think this question is more semantics and specifics, he/she may not have liked climbing or descending as your only answer really, getting out of icing is the most important thing whatever the direction is, but I agree in general with climb/descent based on information. Asking for an altitude change I assume is implied when you say climb or descend. What you describe here is pretty text-book as far as dealing with icing to my knowledge.

  • $\begingroup$ Welcome to Av.SE. Good advice to figure out what you have before talking to ATC... Aviate, Navigate, Communicate! $\endgroup$
    – Ralph J
    Commented Apr 11, 2019 at 2:05

I don’t know that your answers are wrong, but here’s how I’d answer:

  1. Low voltage: assuming no standby alternator, tell ATC you’ve lost alternator. Check the CB for Alt and reset it once if it has tripped. Assuming it doesn’t hold and if in IMC, declare an emergency and tell ATC you want out of IMC ASAP before your electrics die, so divert or descend to leave IMC if possible. If not possible, divert to the closest airport with an approach and land. Shed load on the battery by shutting down all unnecessary equipment (although it may not be much in IMC). If not in IMC, divert to an airport with services if close by and consider getting the phone number of the tower to use your cell phone in case the radios die.


  1. Assuming non FIKI aircraft: Pitot heat and defrost as you said, carb heat too. If no carb, watch MP and consider alternate air if induction ice appears to affect the engine. If in widespread IMC (ie, not in a localized cumulous cloud, tell ATC, and consider a 180 and return to non icing conditions. Also consider a new altitude to non icing conditions. Consider the “out” that you planned for in your flight plan (you did have outs, didn’t you?). Maybe he didn’t like that you were changing altitudes without telling ATC?

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