Replace Yoke Wheel With PTT

[Pacortho]

Had a Co-Pilot yoke wheel break recently - heard there may be an AD coming out on this. I would like to replace the yoke with one with a PTT. Any suggestions? Comments?

[GAHorn]

Which airplane? Which yoke? PLastic?

Here's the letter which indicates a potential AD is being considered. The letter contains a photo with a typical failure. Notice the failed wheel is PLASTIC...not metal, such as the original yokes in our 170/s. (Another example of why original is sometimes better.)

A06_53 Control Wheel Cracks-Proposed.pdf

(88.33 KiB) Downloaded 515 times

[n2582d]

Had a Co-Pilot yoke wheel break recently - heard there may be an AD coming out on this. I would like to replace the yoke with one with a PTT. Any suggestions? Comments?

Trevor Burward-Hoy at Avion Research has this STC. For only $1250 you can get what is pictured below or you could go to a salvage yard and pick up two used real C-170 yokes and have your avionics guy install the PTT switches for a fraction of Avion's price.

ControlYoke.gif (19.72 KiB) Viewed 13621 times

[blueldr]

I can't believe that anyone could be gullible enough to pay $1250 for "steering wheels" for a C-170.

[lowNslow]

Trevor Burward-Hoy at Avion Research has this STC. For only $1250 you can get what is pictured below or you could go to a salvage yard and pick up two used real C-170 yokes and have your avionics guy install the PTT switches for a fraction of Avion's price.

Gary, is that a airbag in the center - must be for that price.

[GAHorn]

My experience with attempts to modify existing control wheels to incorporate PTT switches have usually met with FAA-disdain. Authorities do not like any machining/drilling operations performed on yokes unless supporting engineering data is submitted for approval. (In other words, forgettaboutit.)

Many inspectors also frown on installing yokes from other models of aircraft unless a basis of approval from the manufacturer or STC holder exists. While this might seem silly in many cases, it might make more sense if one considers that most yokes attach to the control columns in various/different ways and that applied stresses must be shown to be airworthy considering the actual attach-hardware and mount.... plus it must be considered that some yoke installation/movement-geometry may create interference with structure and/or persons where the original installation did not.

The Avion yoke appears similar to the standard Cessna 206-402 yokes of the mid-70's thru mid-80's. But the problem is those yokes mated with large control column tubes (about 1.75" diameter) while the 170 column tubes are only about 1" diameter. Further the 206-402 yokes mated with their columns using flat-plates in conjunction with brackets and MS-screws, while the 170 used a pair of special, long rivets which penetrated the actual tube.... very different methods.

Finally, some yokes adapted to different airplanes will actually limit the elevator travel when compared to original installations.

These are only a few of the considerations of what one might ordinarily believe to be simple change-outs...yet which could actually produce problematical, if not downright dangerous, conversions. I'm not saying it cannot be done...or that you can't find an inspector who will approve some particular adaptation...but it's not awlays as simple as it might at first glance appear.

By far the simplest, least-expensive mod is usually the "portable" PTT which attaches via a Velcro-strap, such as the Telex unit. No further approval is required. Here's how I did this to my pilot-yoke. Notice that the coiled cable simply passes over the yoke and drapes, allowing yoke movement, then enters (slipped behind/between) the floating/fixed panel, where it's routed to the usual mic/headseat jacks.

click to ENLARGE

[n2582d]

Gary, is that a airbag in the center - must be for that price.

No, the ones with the airbags cost another $1000. You can tell which ones have the airbags because the Cessna logo is inversed. The idea is that if you crash and set off the airbag you will proudly bear a Cessna logo --reading correctly--imprinted on your chest for the rest of your life.

[blueldr]

PTT switches that are attached with a Velcro strap vary in price from $2.50 to $25.00. I have found that when they crap out, and you pry them open, each uses the same micro switch by the same manufacturer.

[cessna170bdriver]

PTT switches that are attached with a Velcro strap vary in price from $2.50 to $25.00. I have found that when they crap out, and you pry them open, each uses the same micro switch by the same manufacturer.

I just bought my third one last year in 1600 hours of flying my 170. That's about $25.00 every 800 hours,or about 3 cents per hour; pretty cheap for what you get. I've found that it's the button, not the switch itself that craps out. Nice thing about the velcro one over internal to the yoke is that not even a logbook entry is required for replacement.

[GAHorn]

PTT switches that are attached with a Velcro strap vary in price from $2.50 to $25.00. I have found that when they crap out, and you pry them open, each uses the same micro switch by the same manufacturer.

I just bought my third one last year in 1600 hours of flying my 170. That's about $25.00 every 800 hours,or about 3 cents per hour; pretty cheap for what you get. I've found that it's the button, not the switch itself that craps out. Nice thing about the velcro one over internal to the yoke is that not even a logbook entry is required for replacement.

My own experience with these things (and headsets as well) is that the coiled cords are what fail. Either their covering deteriorates and shreds...or the internal wires break from flex...or the jack/plugs fail due to the cheap materials used in their construction. I've also discovered that the less-expensive the unit is...the less time elapses between failures.
I specifically mentioned the Telex unit because it's lasted considerably longer than the cheaper ones I bought (and continually replaced) in my other airplanes. The genuine Telex unit pictured above is now 11 years old and still in as good shape as when first-installed.

This is one of those things that deliver what you paid for, in my experience.

[Iceman07]

I can't believe that anyone could be gullible enough to pay $1250 for "steering wheels" for a C-170.

I had the Avion "steering wheels" installed two years ago (Someone, many years ago, took the old, original wheels, inverted them, cut off the cross bar and had them chromed. They kind of looked like cow-horn tyoes after that un-approved modification. I always very much disliked the look and feel of those)

Yes, the Avion's were expensive, but they are very comfortable, and they are legal. Not to mention having the built-in PTT is so nice...

I do not regret for one minute installing the Avions

[hilltop170]

I too, have Telex portable PTTs in the 170 but position them different than most. I normally hold the yoke in the center instead of on the side so I mounted my PTTs under the yoke shaft with the strap around where the two rivits hold the control wheel onto the shaft. They do not show from the cabin and are very natural to activate in that position. They are also hard to see in the picture.

PTT positioned under control wheel shaft

[GAHorn]

Richard,
Where is your required hand-held microphone?

[Jr.CubBuilder]

Is a hand held mic actually required? I was just skimming through the FARs the other day and remember wondering about that.

[GAHorn]

Is a hand held mic actually required? I was just skimming through the FARs the other day and remember wondering about that.

I was afraid someone would get Richard "off the hook" with this question.
It's been awhile since I read the FAR myself and was using faded-memory to jab-at-him...
the rule (as I recall it, I need to dash to the airport and don't have time presently to confirm it) applies to commercial operators (135/121/etc) who operate IFR and use headsets, requiring a handheld microphone as backup.

Pt 91 VFR operators I believe can operate without radios at all.