AeroElectric-List Digest Archive

Mon 12/31/18


Total Messages Posted: 12



Today's Message Index:
----------------------
 
     1. 04:51 AM - Re: Transponder question (Art Zemon)
     2. 05:43 AM - Re: Transponder question (Alec Myers)
     3. 05:48 AM - Re: Transponder question (Alec Myers)
     4. 05:49 AM - Re: Transponder question (Bob Verwey)
     5. 06:05 AM - Re: Transponder question (Alec Myers)
     6. 06:05 AM - Re: Transponder question (Kelly McMullen)
     7. 06:20 AM - Re: Transponder question (Clayton Harper)
     8. 02:58 PM - Engine switch for a rotax 912 uls (DANIEL PELLETIER)
     9. 04:52 PM - Re: Engine switch for a rotax 912 uls (user9253)
    10. 05:38 PM - Re: Re: Engine switch for a rotax 912 uls (GTH)
    11. 09:05 PM - Transponder Antenna (Jeff Page)
    12. 09:12 PM - Re: Transponder Antenna (Kelly McMullen)
 
 
 


Message 1


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    Time: 04:51:59 AM PST US
    From: Art Zemon <art@zemon.name>
    Subject: Re: Transponder question
    Slight clarification, which I just learned about on Friday when I had the inspections (plural) done for my about-to-be-flown-for-the-first-time BD-4c. There are actually two inspections 1. static system leak check, done once 2. transponder check, done every two years The second one didn't worry me but I was *very* relieved that my static system did not leak =F0=9F=98=81 Cheers, -- Art Z. On Sun, Dec 30, 2018 at 11:22 PM Kelly McMullen <kellym@aviating.com> wrote : > For those that don't know the full reg on static system checks...it only > has to be certified once every 2 years, regardless of how many times you > open the system. Now if you change altimeter or encoder, that is > different story. If you just open a connection and put it back together, > any A&P can do a leak check on the system (holds 1000 ft AGL for 1 > minute with no more than 100 ft loss). The certification says the system > meets that leak test, and altitude requirements for the altimeter. -- https://CheerfulCurmudgeon.com/ *"Be kind, for everyone you meet is fighting a hard battle."*


    Message 2


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    Time: 05:43:22 AM PST US
    From: Alec Myers <alec@alecmyers.com>
    Subject: Re: Transponder question
    Transponders have a power output of 100 watts for the duration of a transmi ssion which is only milliseconds long. The average power output is tiny. The y can=99t possibly set fire to anything. They don=99t need thick cables or high power breakers either. Same for DME. On Dec 30, 2018, at 23:49, Paul Millner <millner@me.com> wrote: Technically, I don't think that's strictly true... the rule as I recall it i s that high power transmitters (like our transponders and DME equipment, tha t can output hundreds or even 1,000 watts) must be reinstalled by an A&P or r epair station. The concern is that if the antenna connection isn't properly m ade, it could prove to be a source of ignition, and fires in airplanes are b ad things. >> I hadn't thought much about it until a couple weeks ago when I had the pl ane at the shop for the biennial transponder check. I forgot the log book, a nd he said that if he had to pull the transponder to look at the serial numb er, that it would cost more because they'd have to recertify it. I don't believe that's a general requirement; perhaps it's part of his repai r stations procedures... I don't think an A&P doing an R&R on a transponder, say, to replace another component has to do a recertification, whatever you r guy meant by that term. They just have to determine proper function. Reade rs have a reference? >> So what can happen to a transponder when it's pulled from the rack? If you improperly reinstall it, you can turn a lot of power into heat. Paul


    Message 3


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    Time: 05:48:42 AM PST US
    From: Alec Myers <alec@alecmyers.com>
    Subject: Re: Transponder question
    How is a quick ramp check going to reveal a propagation pattern? Youd need to put the plane in a radiation proof chamber with absorbing walls and youd need to position your calibrated antenna at a range of different angles. Or rotate the aircraft. On Dec 30, 2018, at 23:59, Kelly McMullen <kellym@aviating.com> wrote: In theory, if the connection has slightly different resistance after the pull and re-install, the propagation pattern for a transmitter in the 1030-1090Mhz frequency at 150-250 watts could be slightly different. So, in theory a quick look at the ramp checker should be done. As a practical matter, I've never seen it change anything. Any A&P can install the transponder, but a repair station must certify it. Unless you are the builder (manufacturer) of the aircraft and have a proper test set to be able to certify it yourself as the aircraft manufacturer in the case of a homebuilt. Then there is the matter of the shop being jerks. He could wait a day or two for you to bring in the logs. He could do the ramp check...if it isn't turned on until he gets there it takes 5 min for the transponder to warm up (for the old cavity tube variety) or less for solid state. He can make the choice. If he had inquired before starting the test, he could have pulled the unit, got the serial number and reinstalled before doing the test. He is just forgetting that he is in the customer service business, and you can go elsewhere. For those that don't know the full reg on static system checks...it only has to be certified once every 2 years, regardless of how many times you open the system. Now if you change altimeter or encoder, that is different story. If you just open a connection and put it back together, any A&P can do a leak check on the system (holds 1000 ft AGL for 1 minute with no more than 100 ft loss). The certification says the system meets that leak test, and altitude requirements for the altimeter. > On 12/30/2018 8:48 PM, Rick Beebe wrote: > What is it about a transponder that makes the FAA require it only be installed by a certified shop? Even if it's just been pulled from the rack? I hadn't thought much about it until a couple weeks ago when I had the plane at the shop for the biennial transponder check. I forgot the log book and he said that if he had to pull the transponder to look at the serial number that it would cost more because they'd have to recertify it. So what can happen to a transponder when it's pulled from the rack? > --Rick


    Message 4


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    Time: 05:49:40 AM PST US
    From: Bob Verwey <bob.verwey@gmail.com>
    Subject: Re: Transponder question
    Art, you are about to join a very exclusive club of somewhat flamboyant individuals who, through their fortitude in the pursuit of excellence in their hobby, have finally finished that last task! I always marvel at the fact that a seemingly random collection of bits and pieces numbering thousands, can on a given day defeat the laws of gravity...even if it isn't really so! Well done Mate! Best... Bob Verwey 082 331 2727 On Mon, 31 Dec 2018 at 14:56, Art Zemon <art@zemon.name> wrote: > Slight clarification, which I just learned about on Friday when I had the > inspections (plural) done for my about-to-be-flown-for-the-first-time > BD-4c. There are actually two inspections > > 1. static system leak check, done once > 2. transponder check, done every two years > > The second one didn't worry me but I was *very* relieved that my static > system did not leak =F0=9F=98=81 > > Cheers, > -- Art Z. > > On Sun, Dec 30, 2018 at 11:22 PM Kelly McMullen <kellym@aviating.com> > wrote: > >> For those that don't know the full reg on static system checks...it only >> has to be certified once every 2 years, regardless of how many times you >> open the system. Now if you change altimeter or encoder, that is >> different story. If you just open a connection and put it back together, >> any A&P can do a leak check on the system (holds 1000 ft AGL for 1 >> minute with no more than 100 ft loss). The certification says the system >> meets that leak test, and altitude requirements for the altimeter. > > > -- > https://CheerfulCurmudgeon.com/ > > *"Be kind, for everyone you meet is fighting a hard battle."* >


    Message 5


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    Time: 06:05:05 AM PST US
    From: Alec Myers <alec@alecmyers.com>
    Subject: Re: Transponder question
    Further to this: A transponder transmission is between 2 and 16 pulses of 45uS width. According to Bendix King, the KT76A has a peak power output of 200W. Lets say youre in a busy TCAS environment and your transponder is firing twice per second. Mean radiated power (worst case) will be 200 * 2 * 16 * 45 * 1e-6 = 18mW. Definitely not a risk to anything. On Dec 31, 2018, at 8:41 AM, Alec Myers <alec@alecmyers.com> wrote: Transponders have a power output of 100 watts for the duration of a transmission which is only milliseconds long. The average power output is tiny. They cant possibly set fire to anything. They dont need thick cables or high power breakers either. Same for DME. On Dec 30, 2018, at 23:49, Paul Millner <millner@me.com> wrote: Technically, I don't think that's strictly true... the rule as I recall it is that high power transmitters (like our transponders and DME equipment, that can output hundreds or even 1,000 watts) must be reinstalled by an A&P or repair station. The concern is that if the antenna connection isn't properly made, it could prove to be a source of ignition, and fires in airplanes are bad things. >> I hadn't thought much about it until a couple weeks ago when I had the plane at the shop for the biennial transponder check. I forgot the log book, and he said that if he had to pull the transponder to look at the serial number, that it would cost more because they'd have to recertify it. I don't believe that's a general requirement; perhaps it's part of his repair stations procedures... I don't think an A&P doing an R&R on a transponder, say, to replace another component has to do a recertification, whatever your guy meant by that term. They just have to determine proper function. Readers have a reference? >> So what can happen to a transponder when it's pulled from the rack? If you improperly reinstall it, you can turn a lot of power into heat. Paul


    Message 6


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    Time: 06:05:42 AM PST US
    Subject: Re: Transponder question
    From: Kelly McMullen <kellym@aviating.com>
    You are right...I used the wrong term. It isn't propagation per se, it is the specific output parameters the FAA wants checked, like exact frequency, power, etc. They don't normally change, but the theoretical potential is there, hence a bench check isn't sufficient, there has to be a check of output from the entire system, including antenna, cable and connections to the unit. I've experience a few shops that choose to remove transponder, do bench check, then reinstall and do the ramp check. On 12/31/2018 6:46 AM, Alec Myers wrote: > > How is a quick ramp check going to reveal a propagation pattern? Youd need to put the plane in a radiation proof chamber with absorbing walls and youd need to position your calibrated antenna at a range of different angles. Or rotate the aircraft. > > > On Dec 30, 2018, at 23:59, Kelly McMullen <kellym@aviating.com> wrote: > > > In theory, if the connection has slightly different resistance after the pull and re-install, the propagation pattern for a transmitter in the 1030-1090Mhz frequency at 150-250 watts could be slightly different. So, in theory a quick look at the ramp checker should be done. As a practical matter, I've never seen it change anything. Any A&P can install the transponder, but a repair station must certify it. Unless you are the builder (manufacturer) of the aircraft and have a proper test set to be able to certify it yourself as the aircraft manufacturer in the case of a homebuilt. > Then there is the matter of the shop being jerks. He could wait a day or two for you to bring in the logs. He could do the ramp check...if it isn't turned on until he gets there it takes 5 min for the transponder to warm up (for the old cavity tube variety) or less for solid state. He can make the choice. If he had inquired before starting the test, he could have pulled the unit, got the serial number and reinstalled before doing the test. He is just forgetting that he is in the customer service business, and you can go elsewhere. > > For those that don't know the full reg on static system checks...it only has to be certified once every 2 years, regardless of how many times you open the system. Now if you change altimeter or encoder, that is different story. If you just open a connection and put it back together, any A&P can do a leak check on the system (holds 1000 ft AGL for 1 minute with no more than 100 ft loss). The certification says the system meets that leak test, and altitude requirements for the altimeter. > >> On 12/30/2018 8:48 PM, Rick Beebe wrote: >> What is it about a transponder that makes the FAA require it only be installed by a certified shop? Even if it's just been pulled from the rack? I hadn't thought much about it until a couple weeks ago when I had the plane at the shop for the biennial transponder check. I forgot the log book and he said that if he had to pull the transponder to look at the serial number that it would cost more because they'd have to recertify it. So what can happen to a transponder when it's pulled from the rack? >> --Rick > > > > > > > >


    Message 7


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    Time: 06:20:13 AM PST US
    From: Clayton Harper <claytonharper@mac.com>
    Subject: Re: Transponder question
    Even though you are not an A&P, it is permissible for you to read the FARs.;):) Look up 91.411 and 91.413. Those will tell you what is required, and who can do what. One will mention FAR 43 Appendix E and F. While you are in that area look at Appendix A and D. If you read those you will know 80% more than 50% of aircaft mechanics. You may also enjoy Todd Snider Statisticians Blues. Fun is challenging aviation pros to give you a reference. Sent from my iPhone > On Dec 31, 2018, at 7:46 AM, Alec Myers <alec@alecmyers.com> wrote: > > > How is a quick ramp check going to reveal a propagation pattern? Youd need to put the plane in a radiation proof chamber with absorbing walls and youd need to position your calibrated antenna at a range of different angles. Or rotate the aircraft. > > > On Dec 30, 2018, at 23:59, Kelly McMullen <kellym@aviating.com> wrote: > > > In theory, if the connection has slightly different resistance after the pull and re-install, the propagation pattern for a transmitter in the 1030-1090Mhz frequency at 150-250 watts could be slightly different. So, in theory a quick look at the ramp checker should be done. As a practical matter, I've never seen it change anything. Any A&P can install the transponder, but a repair station must certify it. Unless you are the builder (manufacturer) of the aircraft and have a proper test set to be able to certify it yourself as the aircraft manufacturer in the case of a homebuilt. > Then there is the matter of the shop being jerks. He could wait a day or two for you to bring in the logs. He could do the ramp check...if it isn't turned on until he gets there it takes 5 min for the transponder to warm up (for the old cavity tube variety) or less for solid state. He can make the choice. If he had inquired before starting the test, he could have pulled the unit, got the serial number and reinstalled before doing the test. He is just forgetting that he is in the customer service business, and you can go elsewhere. > > For those that don't know the full reg on static system checks...it only has to be certified once every 2 years, regardless of how many times you open the system. Now if you change altimeter or encoder, that is different story. If you just open a connection and put it back together, any A&P can do a leak check on the system (holds 1000 ft AGL for 1 minute with no more than 100 ft loss). The certification says the system meets that leak test, and altitude requirements for the altimeter. > >> On 12/30/2018 8:48 PM, Rick Beebe wrote: >> What is it about a transponder that makes the FAA require it only be installed by a certified shop? Even if it's just been pulled from the rack? I hadn't thought much about it until a couple weeks ago when I had the plane at the shop for the biennial transponder check. I forgot the log book and he said that if he had to pull the transponder to look at the serial number that it would cost more because they'd have to recertify it. So what can happen to a transponder when it's pulled from the rack? >> --Rick > > > > > > > >


    Message 8


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    Time: 02:58:18 PM PST US
    Subject: Engine switch for a rotax 912 uls
    From: DANIEL PELLETIER <pelletie1959@me.com>
    Hi Bob, I'm in process to install a Rotax 912 in my airplane. Previously I had a subaru EA81 and I had completed my electrical installation per your diagram with the double ignition. I figure an installation with 2 batteries, no alternator, a ducatti regulator. My airplane is equiped for night flight (nav lights, icom A200, intercom, transponder At 50). I use mechanical engine and flight instruments.) My question: what is the better schema to switch my electrical installation? Daniel Envoy de mon iPad


    Message 9


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    Time: 04:52:56 PM PST US
    Subject: Re: Engine switch for a rotax 912 uls
    From: "user9253" <fransew@gmail.com>
    By "No Alternator", I assume that you mean no external alternator. But your engine does have an internal dynamo, correct? Do you have Bob Nuckolls' book? Download it at http://www.aeroelectric.com/Book/AEC_R12A.pdf Individual schematics can be downloaded at http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/ Z-16 would be a good starting point. I would use a 30 amp fuse instead of a dynamo fuselink. What kind of airplane is it? Post your intended wiring diagram to get suggestions from others. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=486628#486628


    Message 10


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    Time: 05:38:49 PM PST US
    Subject: Re: Engine switch for a rotax 912 uls
    From: GTH <gilles.thesee@free.fr>
    Le 01/01/2019 01:52, user9253 a crit: > > By "No Alternator", I assume that you mean no external alternator. But your engine does have an internal dynamo, correct? > Do you have Bob Nuckolls' book? Download it at http://www.aeroelectric.com/Book/AEC_R12A.pdf > Individual schematics can be downloaded at http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/ > Z-16 would be a good starting point. I would use a 30 amp fuse instead of a dynamo fuselink. Daniel, I'll second Joe's answer. If your engine is a 912, it doesn't require a second battery and Z16 is adequate. But your mention of two batteries rings a bell. Do you rather mean the more recent fuel injected, electrically dependent, 912 iS ? Then it is another kettle of fish and you'll need several separate switches. Season's greetings -- Best regards, Gilles http://contrails.free.fr


    Message 11


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    Time: 09:05:14 PM PST US
    From: Jeff Page <jpx@qenesis.com>
    Subject: Transponder Antenna
    I am installing a Garmin 335 transponder, using an existing antenna that has been on the aluminium airplane for decades. It is a blade style. I was surprised to measure with the ohm meter between the cable shield and the air frame and found infinite resistance. I would have expected the antenna to have a very good connection to the aluminium skin. Or is this some kind of dipole antenna and the measurement to be expected ? I don't want to power on the transponder until I know the antenna is correct. Thanks and Happy New Year ! Jeff Page Dream Aircraft Tundra #10


    Message 12


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    Time: 09:12:59 PM PST US
    Subject: Re: Transponder Antenna
    From: Kelly McMullen <kellym@aviating.com>
    Have you measured between the ground side of the antenna BNC connector and airframe ground? Or is that what you meant? On 12/31/2018 10:03 PM, Jeff Page wrote: > > I am installing a Garmin 335 transponder, using an existing antenna that > has been on the aluminium airplane for decades. It is a blade style. > > I was surprised to measure with the ohm meter between the cable shield > and the air frame and found infinite resistance. I would have expected > the antenna to have a very good connection to the aluminium skin. > > Or is this some kind of dipole antenna and the measurement to be expected ? > > I don't want to power on the transponder until I know the antenna is > correct. > > Thanks and Happy New Year ! > > Jeff Page > Dream Aircraft Tundra #10 > > > > >




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