EricJ Posted June 21, 2020 Report Share Posted June 21, 2020 2 minutes ago, Bob - S50 said: Eric, you seem to be pretty sure. Since there are several of us that feel pretty strongly the other way, the only way to tell for sure is to ask those in authority: I'm pretty sure about what I see in the Garmin STC and Installation Manual say, even though they self-contradict a little bit. I've already said I'm not claiming my input to be gospel, but G5-as-primary-AI installations without TCs in IFR airplanes are not rare if there is an AI in place of the TC. As I've quoted, this is also straight out of the G5 installation manual. This is directly to the OP's original question, so it seems relevant to me. Whether a G5 installed as an HSI can be counted as a TC may be a stretch, admittedly, but that's not completely clear in the G5 docs either way. Being able to replace a TC with a G5 is clear. Since a G5 switches between AI and HSI on demand easily, it makes it pretty reasonable to ask the questions and not make assumptions either way. 2 minutes ago, Bob - S50 said: 1. Write to Garmin and ask: This is not my issue, so no thanks. Quote Link to comment Share on other sites More sharing options...
LABravo Posted July 10, 2020 Report Share Posted July 10, 2020 FWIW My engine mounted standby vacuum failed and had it removed as there is no repair or replacement available. Replaced the TC with an RC Allen 2610 backup AI with TC built in. All-in installed cost $3.5K, about half of a Garmin G5. Works as advertised. Quote Link to comment Share on other sites More sharing options...
carusoam Posted July 10, 2020 Report Share Posted July 10, 2020 Congrats on your first post LAB! Which engine mounted standby vaccuum did you have? Most long bodies have their standby vac system mounted in the tail cone... Plenty of used ones are available as many are getting replaced going all electric.... +1 on the second AI... much better than a TC. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
robert7467 Posted July 12, 2020 Report Share Posted July 12, 2020 I have the mid continent electric AI and added a turn coordinator to it. Quote Link to comment Share on other sites More sharing options...
jamesm Posted July 13, 2020 Author Report Share Posted July 13, 2020 11 hours ago, robert7467 said: I have the mid continent electric AI and added a turn coordinator to it. I see the the ball on the AI , but where is the rate of turn coordinator portion located on the AI on Mid Continent? Do you have pictures or a model number? Thanks change of subject. BTW the Instrument was able to repair my TC at no cost to me. Now it sounds much more normal whereas before it sound like some one ran over a cat/flat spot on the bearing or something. Apparently these TC gyro's can on be repair/overhauled so many times before the parts to repair them are more expensive than repair it self. James '67C Quote Link to comment Share on other sites More sharing options...
robert7467 Posted July 13, 2020 Report Share Posted July 13, 2020 5 minutes ago, jamesm said: I see the the ball on the AI , but where is the rate of turn coordinator portion located on the AI on Mid Continent? Do you have pictures or a model number? Thanks change of subject. BTW the Instrument was able to repair my TC at no cost to me. Now it sounds much more normal whereas before it sound like some one ran over a cat/flat spot on the bearing or something. Apparently these TC gyro's can on be repair/overhauled so many times before the parts to repair them are more expensive than repair it self. James '67C Its the 4300 313 I believe. Now, it does not give rate of turn, but the literature says it's a direct replacement of a turn coordinator. I guess for rate of turn you will just have to do the math. On my old TC, I would only look at the ball anyways, so I am not missing it. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted July 13, 2020 Report Share Posted July 13, 2020 For IR flight, rate of turn is used to stay within the protected zone when turning at intersections... With modern equipment, turn anticipation, is used to really stay within the lines... Anticipation gives a start turn warning prior to arriving at the intersection... modern AIs have a form of the ball on the display... often a rectangle near the triangle pointer at the top... If using a second old style mechanical/electric gyro... a ball can be added to it... or mounted on the panel... In the math section of the IR text book is a few examples of bank angle vs. speed for standard rate turns. Somewhere along the way the FAA decided to allow the substitution of an AI with a ball to be substituted for a TC... In case I missed it... the ball is all about coordination... the best way to turn. PP thoughts only, not a CFI... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
jamesm Posted July 13, 2020 Author Report Share Posted July 13, 2020 RCA 2610-3 SERIES DIGITAL ATTITUDE INDICATORS - 3 INCH - FAA TSO I don't see that it is TS0'd for turn coordinator C3? wonder why Quote Link to comment Share on other sites More sharing options...
carusoam Posted July 13, 2020 Report Share Posted July 13, 2020 Interesting... That instrument comes with a bunch of options to include a rate display too... https://www.aircraftspruce.com/catalog/inpages/rca2610.php?CHOSEN_LANGUAGE=pt you have to click on the options to include turn rate... and slip indicator... How TSO’d does it need to be..? (beyond my skills) I’m guessing C4c is not better than C3? They mention this at the bottom of their page... FAA Specification Conformance: TSO-C4c, TSO-C113a, DO-160F & DO-178B Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Bob - S50 Posted July 13, 2020 Report Share Posted July 13, 2020 Maybe I don't get it. I can't remember the last time I cared about making a standard rate turn. AC 91-75 allows you to replace a TC with an AI as long as it has a separate power supply. There is still a requirement to have a skid/slip ball but not a rate of turn indicator. 2 Quote Link to comment Share on other sites More sharing options...
squeaky.stow Posted July 13, 2020 Report Share Posted July 13, 2020 Seems to me that any confusion about what instrument of any sort can legally replace a Turn Coordinator/ Turn & Bank / Turn and Slip is mostly generated by people who focus too much on the strict letter of the law (or STC) and forget (or never understood) the intent behind them. Installers who don’t fly and inspectors who don’t fly enough often fall into that category. It helps to remember what each instrument can and can’t do. Turn Coordinator: Call it a TC, T&B or T&S, they all do the same thing. They have a gyro mounted at 30 degrees to sense rate of turn via gyroscopic precession and display it with either a vertical needle or an airplane symbol. The needle tells you the rate of turn and is usually marked with an index for a rate 1 turn. It WILL NOT tell you your angle of bank. You have to add the second part of the instrument, the slip ball to “coordinate” the turn and you have to know your TAS and do some math. (10% of TAS + 7 = rate one) If the ball is centred, and you know your TAS you can calculate your angle of bank. If the ball is not centred, you have absolutely no idea what your bank angle is. Attitude Indicator: Will display your bank angle (and pitch) but WILL NOT tell you your rate of turn. If combined with a slip ball (and centred) and you know your TAS, you can calculate your rate of turn. But if the ball is not centred, you still know exactly what your bank angle is. HSI or Heading Indicator: Will show your heading but will not tell you your rate of turn other than retroactively by timing. It CAN NOT replace a TC because it can’t perform either function of a TC, which are 1) keeping you right side up and 2) keeping your rate of turn within your intended limits. So how important is it to know my rate of turn? It is pretty hard to bust protected airspace in a Mooney by going too fast. As long as you use about 15 -25 degrees of bank you will never have to worry about coming close. Far more important from a safety perspective is our ability to keep the blue side up if we lose our primary attitude indicator. Being able to switch to a standby attitude indicator with a display that we are used to flying with is a lot safer than switching back to 1920s technology. If we are using a TC in place of our primary attitude indicator we are maintaining wings level with a much more primitive tool AND we are forced to deduce pitch attitude by monitoring and reacting to airspeed and VSI. It can be done, but there is a reason why the old airmail pilots didn’t live very long! As long as you are replacing your TC with an attitude indicator that has the ability to display slip, either with an old fashioned slip ball or an integral slip indicator, AND it has a source of power that is independent from the source for your primary AI, you are meeting the intent of being able to determine your rate of turn and keep the airplane right side up and the intent of protecting against a dual failure of attitude reference. I’m not saying the inspector or installer will agree with me, but if they don’t they are looking way too closely at the trees and missing the forest in my opinion. 2 Quote Link to comment Share on other sites More sharing options...
LABravo Posted October 17, 2020 Report Share Posted October 17, 2020 On 7/12/2020 at 6:25 PM, jamesm said: RCA 2610-3 SERIES DIGITAL ATTITUDE INDICATORS - 3 INCH - FAA TSO I don't see that it is TS0'd for turn coordinator C3? wonder why Spoke with company, the 2610 is covered by TSO-C4C Quote Link to comment Share on other sites More sharing options...
LABravo Posted October 17, 2020 Report Share Posted October 17, 2020 On 7/10/2020 at 2:55 PM, carusoam said: Congrats on your first post LAB! Which engine mounted standby vaccuum did you have? Most long bodies have their standby vac system mounted in the tail cone... Plenty of used ones are available as many are getting replaced going all electric.... +1 on the second AI... much better than a TC. Best regards, -a- This aircraft had an engine mounted unit manufactured by Parker Aerospace (and subject of two Mooney Service Bulletins). There are actually two part numbers on the drawings, with the engine mount shown as an alternate. To purchase he electric tail mounted system, that with the required plumbing, Mooney like $7.5K for the kit. Add another $2K to install, i was looking at $10K. Next up, remove the vacuum system, gyro instruments and replace with two GI-275s. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted October 18, 2020 Report Share Posted October 18, 2020 Lately... Alternators come in pairs... Attitude indicators come in pairs... A pair of batteries is common... Lots of displays are paired with their own batteries... Vacuum systems are getting pared.... by the dozens... around here... Going all electric was new about a decade ago... when Craig (Chief MSer) was putting extra Aspen screens In his M20J... he probably added an extra pair of Aspens to an existing one... PP thoughts only, not promoting pairing or paring of vacuum systems.... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
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