Welcome Guest. Sign in or Signup

3 Answers

Electric fires, failures, circuit breakers, and bus bars

Asked by: 2421 views , , ,
Aircraft Systems

I am currently flying a TB20, amazing airplane performance.

the question I have is about what to do in the event of an electrical fire or alternator failure. The POH says, just like most, to disengage all electricity, and then slowly bring things back on to either find out what is causing the fire, or, if an electirc failure, to reduce electric load and only bring on the minimum Items needed to preserve power. The TB20 has 3 bus bars, each with their own pull-type breaker. It says, in case of fire, to methodically bring each bus back on, and identify which bus is the problem, and then to identify which item on that bus is the problem, engaging each individual item one at a time. 

My two questions are...

how do you test individual items if they dont have a pull type breaker, but only a push to reset? Is there a way of disengaging the non-pull breakers?

Is this a safe practice, is it worth trying to find the faulty item, or should I just accept that it is the entire bus that is bad? The important  things (gear, etc) have their own pull breaker.

Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

3 Answers



  1. Sam Dawson on Jan 22, 2013

    I would recommend against resetting electrical systems that are not critical to the safety of the flight in the event of an electrical fire. The TB20 POH was probably written before the NTSB and FAA came out with some recent recommendations on circuit breaker resetting and electrical system failures.
    Here is a copy of the NTSB accident report that led to these recommendations. Important stuff reference electrical systems and failures begins on page 15.
    http://www.ntsb.gov/doclib/reports/2009/AAR0901.pdf

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  2. Bob Watson on Jan 23, 2013

    Thanks for the link to the report.

    That’s enough to keep me from doing any in-flight troubleshooting of the electrical system. Page 22 of the report mentions how resetting a tripped breaker without knowing what tripped it can cause a problem to get out of hand if the wiring is damaged each time the breaker is reset.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  3. Sam Dawson on Jan 23, 2013

    Here is a link to the FAA safety bulletin that wash published in response to this accident.

    http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSAIB.nsf/0/533f00940de268ab862576ab0059b26a/$FILE/CE-10-11R1.pdf

    Interesting to note that the FAA recommends that this information be reviewed during initial training, recurrent training and flight reviews.

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes


The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.