The International Cessna 170 Association

See photos for context.

The Initial question is whether or not the electric gyro turn coordinator in my panel could be legally removed and replaced with a simple slip/skid indicator. After digging through the TCDS it seems this would be governed by CAR3 - 3.655 Required basic equipment. I don't see a turn coordinator listed.

Follow up question #1: Has CAR 3.655 been superseded by 14 CFR 91.205?
Follow up question #2: The original equipment list from 1954 shows ITEM NO 607 as a STALL WARNING INDICATOR but then lists 9 other items, one of which is a "TURN & BANK". It later lists item 607 as required equipment. Is Turn and Bank part of ITEM NO 607?

The TCDS also specifically lists Item 607 as required, but then lists ITEM 607 as only the "stall warning kit".

My conclusion is that I could remove the turn coordinator if I chose to. Agree?


Equip list from 11/8/54: TCDS:

1) CAR 3 still governs the requirements for our planes.

2) No, item 607 is only the stall warning kit and it is still a required piece of equipment. The 1954 equipment list showing the installed equipment was used to determine what was in the plane when it was weighed. It doesn’t have anything to due with what’s required. CAR 3.655 and the TCDS A-799 rev 15 determine the required equipment

IMO, you can remove the T&B.

To contribute in addition to Pete’s comments... A “turn coordinator” is a term which references a specific type of rate-of-turn indicator in which the “needle” of a turn-and-bank is replaced with a depiction of a banking airplane. A rate-of-turn indicator is required for instrument flight except when a third attitude indicator is provided which operates in 360-degrees of pitch and roll. Most rate-of-turn indicators of both types incorporate the “slip-and-skid” (inclinometer), hence the “Needle-and-ball” term commonly used. (I’d personally advise against removing it, even if you only intend to operate VFR because in the event you ever inadvertently enter instrument conditions it might prove to be a life-saver if your attitude indicator (artificial horizon) should “tumble”.)
As a further note of interest, only the B-model is required to have the stall warning system although many A-models had it as optional equipment.

Having an AHRS stratus 3 or other device may be far more beneficial than keeping a slightly unreliable T&B or TC instrument in your aircraft. What I would say is that if you don't have the portable AHRS, then you might want to keep something like a T&B or TC. If you have an AHRS system (portable or otherwise), then the T&B or TC is far less important from a VFR perspective.

My understanding (from a CFI perspective) is that T&B or TC is NOT required for VFR flight for our C170's. But it's good to have, unless you have a backup. Also, if you ever get in to a spin (in the clouds or elsewhere), the only instrument that can help if you are completely, totally confused, is the TC or T&B.

YMMV.

Tailwinds,
DC

I am strictly a VFR guy but for much of last summer, severe forest fires gave us smoke filled skies and limited vis in many areas. Flying along Cook Inlet with its gray glacier water merging with gray skies and smoke is not very appealing and can turn serious very quickly.

When my AH failed (DG had been dead for a while) I decided to skip rebuilding the old vacuum instruments, removed the venturis and all the old plumbing, and put in a Dynon D3. I understand the appeal of the vintage systems but the D3 is just superior as far as I am concerned. Regardless less if required by regulation, something like a D3 or workin DGs and AHs can be lifesavers.