Nukemzzz Posted June 21, 2020 Report Posted June 21, 2020 While working on my PPL (still in process) I found that the standard training information didn’t get into enough detail for me personally. I think it’s partly because I’m an engineer, and partly because I don’t learn through memorization. I don’t feel like I’ve learned something until I precisely understand “why”. Once I know “why” I can forget the training because I’ve now internalized the facts. I’m also very independent in this way. I don’t “believe” what anyone tells me. I mark it as a possible truth and don’t believe it until I understand “why“ and agree with it. Makes me harder to train than the normal individual perhaps...but when I get it, I really get it. This morning finally I came across a video series that efficiently fills this need better than any other source that I’ve found and I wanted to share it. It seems to be some normal guy on YouTube doing his own video series. It’s very well done, gets to the point, and graphical illustrations makes it easy to follow the “why”. If you are a CFi I think these videos could help you train someone hard headed like me. Lol I've been trying to determine if I wanted a TC or T&B in my new instrument panel. I saw talk on these forums about the pros and cons. The video below is an example of his work. It makes it clear why the TC can be dangerous in IMC. And this one shows why an AI has to reset if you do a loop: I’m subscribed now I recommend you check this series out if you are engineering minded like myself 2 Quote
carusoam Posted June 21, 2020 Report Posted June 21, 2020 Nuke... There are many levels of engineers around here... there is even a couple of professors at fine engineering schools around here... You are not alone... But why be impressed with the row of trees up front... when there is a whole forest just beyond that first line...? TnBs stopped getting installed when the TC became available... same device with its internal gyro mounted on an angle... Realistically the TC became outdated when Attitude Indicators became so cheap to manufacture... or acquire... People become overwhelmed... with failures in IMC... Of course... engineers aren’t ordinary people... they train for instrument failures in simulated IMC.... thus proving to themselves... Go Engineers! Just remember... sometimes the engineers would like to get help from the other teams.... don’t accidentally set up an us vs them environment... Best regards, -a- 2 Quote
Hank Posted June 21, 2020 Report Posted June 21, 2020 (edited) This engineer likes the TC, and not nhst because it has elecgric and vacuum power. and supplies information to my Brittain autopilot. In IMC, the Attitute Indicator (= Artificial Horizon) is primary for attitude, and the DG is primary for holding a straight line with TC secondary. But the TC is primary when turning (I only make standard rate turns in IMC unless ATC asks for half-rate). BSME, MSE Oops, you're still working on your ticket @Nukemzzz. When flying VFR, I use the horizon out the frint windshield tomgo straight (with occasional glances at AI and DG), and the horizon (with occasional glances at AI and DG) to make turns. The only feal use I remember for the TC as a VFR pilot was when mountain obscuration didn't clear up as forecast, the hilltops became obscured below me and something white shot by the windshield. I locked eyes in the TC, rolled into a standard rate left turn, verified altitude level on AI and checked heading on DG. Rolled out nicely on the reciprocal heading and went home. Called Mom after landing to cancel the visit . . . . Edited June 21, 2020 by Hank 2 Quote
MooneyMitch Posted June 21, 2020 Report Posted June 21, 2020 Definition of an engineer: somebody who makes precise guesswork based on unreliable data provided by people with questionable knowledge. Never wrong. Likes tables. 1 2 Quote
Nukemzzz Posted June 21, 2020 Author Report Posted June 21, 2020 Haha... This may or may not be typical of engineers. And I realize there are more engineers here... probably half if I had to guess...which makes my post useful to maybe half of you. I'm simply saying that I'm the type of person that doesn't just believe what I'm told. I have to understand the why and agree the assessment is correct before I believe anything. Just sharing a video series that I found useful for understanding these details more quickly. 2 Quote
Nukemzzz Posted June 21, 2020 Author Report Posted June 21, 2020 1 hour ago, carusoam said: Nuke... There are many levels of engineers around here... there is even a couple of professors at fine engineering schools around here... You are not alone... But why be impressed with the row of trees up front... when there is a whole forest just beyond that first line...? TnBs stopped getting installed when the TC became available... same device with its internal gyro mounted on an angle... Realistically the TC became outdated when Attitude Indicators became so cheap to manufacture... or acquire... People become overwhelmed... with failures in IMC... Of course... engineers aren’t ordinary people... they train for instrument failures in simulated IMC.... thus proving to themselves... Go Engineers! Just remember... sometimes the engineers would like to get help from the other teams.... don’t accidentally set up an us vs them environment... Best regards, -a- I understand that you and many others on here prefer just adding another AI instead of the T&B or TC. This isn't practical for me at the moment..bounded by time, money, and room behind the panel (I have limited capacity for more complexity being added to this project and I'm about $25k deep in surprise expenses for this so far this year). Also, my CFI just reviewed AIM with me for IFR and says I need a T&B or TC. (Yes I understand this can be done with math...says turn rate device..but seems easier to not do this for training). My situation is the picture below. I have one heck of a mess on my hands. Not seen in the picture is the engine out, motor mount frame out, flap pump out, and I'm about to pull the step servo. I have two panels getting waterjet at the moment. I'm putting 8 x 3 1/8" gage holes on the left. I was thinking about leaving the Mitchel 2 1/4" T&B out and instead installing a 3 1/8" used T&B or TC since I have it all apart and the last date on this Mitchel device is like 1978 (one year younger than me...lol). Quote
Nukemzzz Posted June 21, 2020 Author Report Posted June 21, 2020 The key learning that I picked up from the T&B vs TC video is if you are banked left, and start to roll back level, the TC will indicate that you are banked right. This sounds super confusing if you are flying partial panel. Makes me think I should put the old ball and needle system in this empty hole since, while it's not perfect, there isn't a picture that lies. Quote
Jerry 5TJ Posted June 21, 2020 Report Posted June 21, 2020 The TC / T&B instrument can be replaced with a second AI. AC91-75 3 Quote
Hank Posted June 21, 2020 Report Posted June 21, 2020 1 hour ago, Nukemzzz said: The key learning that I picked up from the T&B vs TC video is if you are banked left, and start to roll back level, the TC will indicate that you are banked right. This sounds super confusing if you are flying partial panel. Makes me think I should put the old ball and needle system in this empty hole since, while it's not perfect, there isn't a picture that lies. Use the AI to establish your bank angle, and support it with the TC. Standard rate turns in I.C are established with the AI, then the TC is used to maintain standard rate until you roll wings level on the new heading. Quote
EricJ Posted June 21, 2020 Report Posted June 21, 2020 1 hour ago, Nukemzzz said: The key learning that I picked up from the T&B vs TC video is if you are banked left, and start to roll back level, the TC will indicate that you are banked right. This sounds super confusing if you are flying partial panel. Makes me think I should put the old ball and needle system in this empty hole since, while it's not perfect, there isn't a picture that lies. For partial panel I much prefer a TC, as it does provide immediate roll information, even though it is rate of roll and not position. If you lose the AI, the TC is far more responsive to roll indication than the indirect response of a T&B. Whether you're banked or not is evident in the DG, which also indicates turn rate information. 2 Quote
Nukemzzz Posted June 21, 2020 Author Report Posted June 21, 2020 3 minutes ago, EricJ said: For partial panel I much prefer a TC, as it does provide immediate roll information, even though it is rate of roll and not position. If you lose the AI, the TC is far more responsive to roll indication than the indirect response of a T&B. Whether you're banked or not is evident in the DG, which also indicates turn rate information. Good info, so it can be done. TC are more available used in good condition it seems. If they will work, then I might just go with one of those for now. At some point I’ll likely upgrade to solid state stuff, but for now I’m just trying to get it back IFR legal, and decent looking, with minimal effort and cost, and I don’t want to put the old 2 1/4” mitchel back in. Quote
carusoam Posted June 21, 2020 Report Posted June 21, 2020 TCs by the book... are great devices... they are always working like brand new... until they a worn... They won’t surprise you in IMC... unless you don’t pay attention to it until after you need it... Things to pay attention to... how responsive is it in bumpy VMC? Is it stable enough to follow? Typically, a new or OH’d TC works as the IFR books describe... Where they fall down is with wear... So... when you train using partial panel... make sure you use it in bumpy conditions... Expect when you need to use it... it may be nice and smooth at altitude... and may get very bumpy somewhere below 5k’ agl... See Jerry’s post above about the legal aspect of using an AI in place of a TC... And... there are other devices like a Dynon D10 portable... This is advice regarding how not to be surprised by your instrument’s behavior... Simple worn instruments are a set-up for major failure in bumpy IMC. If your vac pump fails after 500hrs of use... you are stuck using the TC to keep the sunny side up... If your TC has many thousands of hours on it and flops around in the bumps.... You now recognize how terrible this situation would be... Basically have a really good plan B if flying in IMC... PP thoughts only, not a CFI... Best regards, -a- 1 Quote
PT20J Posted June 22, 2020 Report Posted June 22, 2020 6 hours ago, Jerry 5TJ said: The TC / T&B instrument can be replaced with a second AI. AC91-75 Thanks, Jerry, for pointing that out. We still run across CFIIs that are unaware of this. Hal Shevers (Sporty’s Pilot Shop) started petitioning the FAA for this around 1992. Took awhile. A second AI is worth 5 TCs (actually 4.895, but I rounded). OK, I’m kidding, but really everyone, if you only have an AI and a TC, you should seriously consider replacing the TC with an AI if you fly much IMC (unless of course you have a rate-based autopilot). Look up the accident rate for partial panel IMC. There are only two reasons for standard rate turns: 1. It avoids banking too steeply with risk of loss of control. This problem is negated if you have a second AI. 2. It allows timed turns in case the HI fails. But now days, it’s easier just to use GPS track. Skip 5 Quote
Jerry 5TJ Posted June 22, 2020 Report Posted June 22, 2020 13 hours ago, EricJ said: For partial panel I much prefer a TC, I much prefer a second (and third) AI to avoid partial panel completely. 3 Quote
bob865 Posted June 22, 2020 Report Posted June 22, 2020 15 hours ago, EricJ said: For partial panel I much prefer a TC, as it does provide immediate roll information, even though it is rate of roll and not position. If you lose the AI, the TC is far more responsive to roll indication than the indirect response of a T&B. Whether you're banked or not is evident in the DG, which also indicates turn rate information. Sure, but you typically assume that if you lose your AI, you also lose your DG also because they are both vacuum instruments and the more common failure is loss of vacuum than a failure of an instrument. So assuming you have lost both your AI and DG, do you still prefer a TC? Quote
EricJ Posted June 22, 2020 Report Posted June 22, 2020 1 hour ago, bob865 said: Sure, but you typically assume that if you lose your AI, you also lose your DG also because they are both vacuum instruments and the more common failure is loss of vacuum than a failure of an instrument. So assuming you have lost both your AI and DG, do you still prefer a TC? I do personally, yes, because then it would be my best source of roll information. The compass has challenges. 1 Quote
Nukemzzz Posted June 22, 2020 Author Report Posted June 22, 2020 91.205 below... If I’m reading this correctly you don’t need a gyroscopic rate of turn instrument if you have 3 attitude instruments that are usable through 360deg of pitch and roll. AI aren’t usable beyond 85deg of pitch so I don’t believe that’s a way out, and if I’m reading this right...two isn’t enough. I think I’m missing something...how have you determined that two AI satisfies this? Is the argument that AI is a turn rate instrument? It gives you bank and pitch angle not rate right? You can do the math, but it doesn’t say “an instrument that can be used to calculate the turn rate”. i wouldn’t be too hard on CFI’s for not getting it. The language here doesn’t make a secondary AI acceptable as a TC replacement apparent. Quote
Nukemzzz Posted June 22, 2020 Author Report Posted June 22, 2020 And when you install a secondary AI you are using an electric one right? Backup for when the vacuum pump fails. Quote
Hank Posted June 22, 2020 Report Posted June 22, 2020 Dont forget that you also need a slip skid indicator per your screen shot above. Never seen one if those on an AI . . . . Quote
Nukemzzz Posted June 23, 2020 Author Report Posted June 23, 2020 I see the AC bulletin above now. Why don’t they update AIM? Quote
EricJ Posted June 23, 2020 Report Posted June 23, 2020 4 hours ago, Hank said: Dont forget that you also need a slip skid indicator per your screen shot above. Never seen one if those on an AI . . . . They're on most of the digital AI displays. 2 Quote
Hank Posted June 23, 2020 Report Posted June 23, 2020 (edited) 6 hours ago, EricJ said: They're on most of the digital AI displays. Oh yeah, the itty-bitty line below the pointer, with the famous disappearing VSI--only shows up above what, 50 fpm? Because you don't need to know if you're drifting slowly away? Man, I love my IVSI, not sure I want to fly in IMC with an insgrument that has a multisecond lag and disappears when it thinks I don't need it . . . . . Edited June 23, 2020 by Hank Quote
EricJ Posted June 23, 2020 Report Posted June 23, 2020 5 hours ago, Hank said: Oh yeah, the itty-bitty line below the pointer, with the famous disappearing VSI--only shows up above what, 50 fpm? Because you don't need to know if you're drifting slowly away? Man, I love my IVSI, not sure I want to fly in IMC with an insgrument that has a multisecond lag and disappears when it thinks I don't need it . . . . . As cheap and simple and reliable as actual inclinometers are, I don't know why they don't just glue one on every panel somewhere. Even if everything else is glass, a compass and a mechanical inclinometer offer pretty high reliability and consistent behavior. I flew a brand-new Seminole a fair amount recently and it doesn't have a compass. The check pilot for the outfit that has it is one of those 15000 hour guys and said he refused to fly it when they first got it, until they got a letter from Piper explaining that it was Type Certificated without a compass. That was new to him, new to me, and new to the grumpy old IA instructors at my A&P school. This is why I question a lot of things. 2 Quote
carusoam Posted June 24, 2020 Report Posted June 24, 2020 So... The magnetic compass is officially dead? That’s amazing! I thought its time was limited when clocks went digital... Best regards, -a- Quote
Jerry 5TJ Posted June 24, 2020 Report Posted June 24, 2020 5 hours ago, carusoam said: So... The magnetic compass is officially dead? No, just the floating, bobbing, ANDS-ing, leaky kerosene compass. A magnetic heading sensor is still required but a solid state device is certificated. 2 1 Quote
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