Mailing List flyrotary@lancaironline.net Message #21465
From: <sqpilot@bellsouth.net>
Subject: Re: [FlyRotary] Re: Mismarked Fuse??
Date: Fri, 6 May 2005 11:19:34 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Hi, Ian....I was the one who experienced the overheated gear motor/popped CB in a military King Air.  The reason we reset the circuit breaker is because it is SOP. (Standing Operating Procedure).  Standard procedure is to reset the breaker one time (one time only). If it does not pop again, go ahead and use the equipment. Yes, we could have pumped the gear down, but why waste all that time and effort when simply letting the motor cool and resetting the CB would bring everything back on line?  We were also taught that in an emergency, if you lose your commo radio, reset the breaker, and you may get your com radio back long enough to declare an emergency and/or give your position prior to bailing out or ejecting. Paul Conner

----- Original Message ----- From: "Ian Dewhirst" <idewhirst@dewhirst.ca>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, May 05, 2005 10:52 AM
Subject: [FlyRotary] Re: Mismarked Fuse??


Good Morning Ed,

I have read the contact articles you wrote, one of which detailed your
fault tolerant electrical system, I enjoyed reading them and integrated
several good ideas from you along the way.  I agree that six CBs to
support critical flight systems are not going to break the bank or take up
most of the panel in my RV.  I still fail to see the utility in CBs; if a
CB pops I expect that most everyone would switch to the backup system and
hit "go to nearest" on their GPS.  I can here the reply from the list so
let's take that a step further, CB number two pops, what do you do?  If
you push and hold CB number 1 and a fire starts you have a situation that
went from bad to unmanageable, in the immortal words that we read last
week "What are you going to do now?".

Someone recalled a story of a gear motor overheating and popping the CB,
there must be some other way to pump the gear down, why risk the reset,
it's not like you plugged in the vacuum with the kettle on and the breaker
blew at home, there is a good chance that there is a problem.  The CB's I
am familiar with offer no safety valve while you are resetting them, push
and hold for a second could equal fire or equal fused contacts which could
equal fire, please correct me if I am wrong as it would likely change my
mind about CB's.

I suppose that you could get a cheap fuse and have a problem as Paul did,
same thing with a breaker.  Switching to a backup system should solve the
problem without having to reset a breaker or replace a fuse.

Cheers -- Ian


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