W31 Toggle Circuit Breaker (TCB) Switch
The un-insulated braided wire
is the mode of failure.
On July 2nd, 2008 the FAA published
AD 2008-13-17 against many of the Toggle
Circuit Breaker Switches that are found in Beech Aircraft.
This AD requires that certain Beechcraft Part Number circuit
breaker-type switches be replaced in F33, F33A, G33, V35B, A36, A36TC, B36TC,
B55, D55, E55, A56TC, 58, 58P, 58TC, G58 and model 77 Skippers.
It becomes effective August 6th, 2008 and must be complied with
within 12 months following the effective date.
11 June 2009 NEWS FLASH:
ABS has secured an extension* for compliance with this AD. See more info
HERE. Way to
*FAA strings attached
20 November 2009 NEWS FLASH:
GOOD NEWS, Williams Air Parts has received a PMA approval for an alternate
circuit breaker to comply with this AD. The BAD NEWS (reported on 11/4/2009) is
that it's MORE EXPENSIVE than the Tyco/Beechcraft breaker that is being provided
to comply with the AD .
On 11/24/2009 their site reported their PMA'd
breaker at $140 each. See the Williams offering below and read more about the
Williams Air offering
The affected models and SNs extracted from the AD
This AD applies to the following
airplane models and serial numbers that have a part number (P/N) 35-380132-1
through 35-380132-53 circuit breaker toggle switch installed and are
certificated in any category:
Beech Model Serial Numbers
(1) F33 and G33 CD-1235 through CD-1304
(2) F33A CE-290 through CE-1791
(3) F33C CJ-26 through CJ-179
(4) V35B D-9069 through D-10403
(5) A36 E-185 through E-3629 and E-3631 through E-3635
(6) A36TC and B36TC EA-1 through EA-695
(7) 95-B55 TC-1913, TC-1936 through TC-2456
(8) D55 TE-452 through TE-767
(9) E55 TE-768 through TE-1201
(10) A56TC TG-84 through TG-94
(11) 58 TH-1 through TH-2124
(12) 58P TJ-3 through TJ-497
(13) 58TC TK-1 through TK-151
TH-2126, TH-2127, TH-2131 through TH-2134, TH-2136, TH-2137,
TH-2139 through TH-2141 and TH-2143 through TH-2150
(15) 77 Skipper WA-1 through WA-312
Some aircraft could have as
15 of these TCB switches in the airplane. Fortunately, my B55 is not affected by
Allied Electronics also carries the W31 TCB Switch
Read the ABS Article
Read the latest 8/21/2008 ABS
HERE highlighting the "fix" that Tyco has
put into the replacement switch.
Read the 1/26/2009 ABS Update on FAA Refusal
to Re-Review the AD
Read the AD
Read the W31 PDF Spec
Read the FAA Narrative
Read Beech Lister Jim B.'s Breaker Cross
Reference List HERE*
DO NOT RELY ON THIS LIST
NUMBERS OFF THE ONES IN YOUR PLANE
Other Sources for the
Newark @ $21.53 and
Mouser @ $26.27
EDITORIAL COMMENT FOLLOWS:
You know, I really don't understand why it is that only
Beechcraft circuits and airframes are the only places where these circuit
breakers "let the smoke out" and in no other airframes where this breaker design
must have found itself during all these years in the aviation industry. Things
that make you go HMMMMMMM!
Here are the actual Tyco
manufacturer comments regarding these switch designs that were provided to Beech Lister Ron G.
and subsequently reported to me:
1. The old Beech TCB is provided by Tyco
to Beech and isn't available directly from Tyco distributors. Tyco does not
consider it to be obsolete, at least not yet. That old Beech TCB is Tyco part
number W31-X1005-xx. (The last two digits "xx" represent the Amp rating.)
2. The new Beech part is provided by
Tyco to Beech and isn't available directly from Tyco distributors. The Tyco
part number is W31-X1017-xx. It includes the additional internal insulation
that is described in the FAA AD.
3. The Tyco part number W31-X2M1G-xx,
which is available from several distributors including Allied Electronics for
less than $25, Newark Electronics, Mouser, and Spruce, does include the
additional internal insulation as does the W31-X1017-xx part. However, the
toggle handle shape and color is different from the Beech W31-X1017-xx part.
Both the W31-X1017-xx part from Beech and the Tyco W31-X2M1G-xx have the amp
rating stamped into the end of the toggle.
Joe F., a PE and A36 owner in New York, has
provided a picture of the TYCO W31 switch in his panel alongside the Beech OE
switches. Joe affectionately dubs the TYCO switch "The LLC" switch for
"Looks Like Crap" <vbg>! It's the one in the Beacon position....LOL
Nothing but full disclosure here at CSOBeech, so you and your mechanic decide what works for you. Thanks for the
Here's a CB install pirep from Leldon L.
I had told my 78 year old IA I would do the grunt work under
the panel on his 1980 A36... and then we would do mine.
We started this morning on his first... got out all the tools,
lights, fans ( only 100 today in Texas..but about 85 in his A/C hangar, pads,
The first one was definitely the "learning" one. It took me
right at 4 hours total time from start to finish on his seven breakers. (he
needed the ALT CB that I didn't)
With all the tools out and ready... and the experience of
his.... I did my '76 A36's six CB's in ONE hour flat. Three important points I
learned on our airplanes that may not to applicable to all... may not work on
the 84 and newer panels, and maybe the P barons..... don't know enough about the
55/58 barons to say...
1. I learned that if I disconnected the load side of the CB's
it was possible to remove all six CB's on the buss bar as a whole set... that
really really saved a bunch of time. Installed the new CB's on the buss bar
loosely on the workbench.....then reinstall the whole set at one time.
2. Beg, borrow, or steal a set of screw starters.... I used
about a 8 inch one and it worked slicker than xxxxx. No dropped screws on
reinstalling the wire terminals.
3. IF you plan on paying somebody else by the hour to do
yours... I'd use a shop that has done a few... as previously noted... the second
went a MUCH faster.
Of course, disconnect the battery... put down something on the
floor to catch what you drop... you WILL drop something into the bilges if you
Kind of a pisser... to summarize this whole questionable AD...
twelve of the 13 breakers I did today were "Woods"... not supposed to have the
failure mechanism of the AD... the last CB was one I bought 3 years ago from
A source for Screw Starters is
Here is an install pirep from Dr. Dave Rogers
on his experience with his shop's breaker switch install:
At 9AM Monday the A-36 went in for the circuit breaker AD.
There were seven breakers to replace. I handed the shop (SafeFlight at Bay
Bridge W29) the breakers in their original Rapid bags with the appropriate
function for each breaker marked on the bag. I also handed them all the original
paperwork from Rapid. I included a copy of the breaker replacement tables from
the AD with the appropriate entries marked and labeled with the appropriate
function. Finally, I handed them a copy of Leldon's Pirep (above) and explained
how I thought this should go and left to do some odds & ends on the E33A.
This was their first AD job. I wandered back a little over an
hour later. The electrical sub-bus was out of the aircraft on the bench and the
new breakers almost all installed in the sub-bus. I then wandered to my next
meeting. Around noon I got a call that the job was finished, an ops check
performed, the paperwork done and the aircraft would be back in the hangar
shortly. I was pleased.
So, it looks like we have at least one shop in the
Mid-Atlantic region that can do the job in a reasonable amount of time. Let's
keep a list of maintenance shops that have done the AD in a reasonable amount of
Safe Flight at W29
Beech Lister Larry J. reports that he removed 12
CB switches from his A36 in July 2009 and this is what his taxi and landing
light breakers looked like:
Larry says: "they look good as new!" I'm
sure Larry is thrilled that he got them out of there before they melted down and
let all the smoke out.........