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Airspeed indicator stopped mid flight

Posted: 19 Jan 2017, 14:17
by abh_jc_03
I was flying and all of a sudden my airspeed indicator stopped. Pitot heat is on and the pitot cover had been removed before takeoff.

Re: Airspeed indicator stopped mid flight

Posted: 19 Jan 2017, 14:37
by LZ-WIL
Hi,

Did you check the pitot heat fuse? It might appeared on but actually be off if the fuse is out. :wink:

Cheerz,
Will

Re: Airspeed indicator stopped mid flight

Posted: 19 Jan 2017, 14:41
by abh_jc_03
I hit the. ALT FLD fuse and it came back. I don't know what that is but it's back. Thank you.

Re: Airspeed indicator stopped mid flight

Posted: 19 Jan 2017, 16:05
by Oracle427
That is the alternator field circuit breaker.

The alternator does not have any permanent magnets and a magnetic field must be induced by running current through the coils in the alternator.

I have a feeling that your alternator field tripped or never worked at all during this last flight. You may have started on battery power and never noticed it was discharging the entire time. By this point the power would have been insufficient to run the pitot heater and many other accessories.

It doesn't take very long either, in about 30 minutes the battery will be pretty much dead.

Re: Airspeed indicator stopped mid flight

Posted: 19 Jan 2017, 16:16
by abh_jc_03
I'll have to keep an eye on that. I checked the hangar and it showed aircraft in "great shape". But obviously I missed something. Thank you for the response.

Re: Airspeed indicator stopped mid flight

Posted: 19 Jan 2017, 17:02
by Oracle427
I believe tripped circuit breakers don't show up in the hangar, just something to check on. On the RL checklists it is customary to check for tripped breakers before start and after turning on the avionics. This way you can verify whether there was a potential bad condition before you started to use the aircraft and then again verify that one does not exist immediately after powering up all the avionics.

It isn't as easy to check the CB's in the sim as it is to pass your hand over them and feel for tripped ones, but the A2A sim faithfully replicates the outcome even down to dimming lights. :)

Re: Airspeed indicator stopped mid flight

Posted: 20 Mar 2017, 16:20
by Ron Attwood
This has saved me a new thread.
Exactly the same thing happened to me yesterday. C182, mooching along, happy as Larry. Oh API not working. On with the pitot heat and waited for it to warm up...and waited...and waited. Online mates giving helpful advice such as "Is your pitot heat on?" and "Have you removed the pitot cover?" My replies are ex-directory. I examined (and clicked on)every circuit breaker there is plus a few I found under the seat. Still no ASI. I made my landing using the GPS Ground Speed, went to the hangar, all perfect. In fact the man said I look after it very well. Did a walkaround (Something I'm normally very remiss about :( ) Nuffin!
Shut down P3D and restarted with the same aircraft and of course ASI all present and correct.

First time it's happened and frankly I don't suppose it'll happen again. I'm just interested if anyone knows what occurred. :?

Re: Airspeed indicator stopped mid flight

Posted: 21 Mar 2017, 03:48
by Lewis - A2A
If you are using third party weather programs they have been known though rarely to cause the odd issue when it comes to allow pitots to unfreeze. Could that rare issue.

Re: Airspeed indicator stopped mid flight

Posted: 21 Mar 2017, 09:30
by Ron Attwood
Who doesn't use a third party weather engine? :D AS 2016 or OpusFSI as the fancy takes me. It was AS2016 on this occasion. :? As I said, hadn't seen it before and not likely to see it again....I hope. :)