---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 10/11/14: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:25 AM - Re: Should a tripped circuit breaker be reset in flight? (Bill Watson) ________________________________ Message 1 _____________________________________ Time: 09:25:35 AM PST US From: Bill Watson Subject: Re: AeroElectric-List: Should a tripped circuit breaker be reset in flight? > My own preference for not re-setting breakers has > more to do with builder competence in crafting > and pilot competence in carry out a Plan-B. These > are exercises in pre-incident planning that go > to making breaker resets or fuse replacements > irrelevant. > > This isn't about fires, it's about avoiding that > deer-in-the-headlights look that overcomes too > many of our span-can driving brothers. Incidents > described in detail over decades of what I've called the > "Dark n Stormy Night" stories popular with the > journals . . . Sport Aviation not withstanding FWIW, I tried to follow this thinking in my plane. I ended up with 4 breakers and 2 fuse panels in my Z-14). Breakers 1&2 = for (2) LRC3 Voltage Regulators per installation instructions. Breaker 3 = flap motor (my thinking was that flap deployment at highspeeds could/might pop the breaker and I'd like to be able to reset. Casual testing indicated that the motor just 'stalls' or 'slips' but never pops the breaker) Breaker 4 = Autopilot because the TruTrak unit doesn't have an on/off switch. Intent is to use it as an emergency on/off switch. In retrospect after 3 years and 500 hours , Breaker 3 was a mistake and is not needed, a fuse for wire protection would do. Breaker 4 still makes sense to me though such an emergency has never been encountered. However I wish I had either installed 3 additional breakers or at least on/off switches for my (3) GRT EFIS screens. These devices lack on/off switches and are always-on when main power is on. That is how I normally operate. But they are major consumers of electrons and any load shedding exercise would benefit from being able to shut down 1 or 2 of them. With 2 batteries and 2 alternators, all scenarios that involve loss of a single battery or alternator allow me to complete the flight without a problem with all (3) on. But starting a cold engine, on a cold day, with the critical battery drawn down (the one without the (3) EFISs) can be impossible unless the (3) EFISs are taken off line. It's happened and it's required pulling their fuses. If I maintain and manage my batteries properly, this should never be a problem; but I didn't and it was. On the other hand it's just an on-the-ground non-emergency situation. In the end, only the (2) breakers for the LRC voltage controllers are needed. I would like all my avionics to have an on/off capability. For those devices that don't (AP and the 3 EFISs), it seems that breakers can serve as infrequently used on/off switches. Bill "happily flying with a fully equipped kitchen and sink" Watson Addendum: One other thing that breakers can do for you is to visually indicate what circuit popped. LED equipped blade fuses can do the same and do it quite well. My fuse panels are installed in the passenger seat foot well and have transparent panels. While not easily reached by the pilot in flight, they are easily visible. Combined with a panel diagram (or transparent panel labeling) it is easy to see what fuse is popped. The only fuse that ever popped in flight was for the strobe unit. The fix was to replace the unit with one that didn't require a power run from the rear mounted battery, forward to the on/off switch, and back to the rear mounted strobe unit. Now there is an unreachable inline fuse between the battery and the strobe unit. The on/off switch controls the unit via some sort of relay. ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.