Revision to Tripoli Rule Regarding Wireless Remote Switches

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rrobe99999 said:
Does anybody remember this ruling from TRA vs BAFTE? "The agency's decision does not satisfy the standard for evaluating agency rulemaking because it was arbitrary and capricious, an abuse of discretion, or otherwise not in accordance with the law" From what I have read on this post, TRA membership does not want this rule change. Who does the BOD represent? There is no precedent or legal reason to make the rule change. It should be a recommendation. Allow RSOs to make the decisions regarding what they feel is safe and how to set up the range. Flyers have the burden to prove that their design is safe. All of the devices discussed in this thread can be used in a safe or unsafe manner depending on the flyers design and procedures (It is highly unlikely that a flyer would set off Wi-Fi enabled initiators using the test page, but possible). No burden or liability should be placed on any vendor of these products. They already work hard enough for marginal profits. Chris, your instructions are outstanding and do not need to be rewritten.
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OMG!
 
Steve Shannon said:
This response baffles me. Cris and the other manufacturers of solid state, firmware controlled switches have been very consistent in defending their designs. We (Tripoli) said that for now, we want a physical disconnection until taken out on the range. Seriously, I appreciate their patience and willingness to work with us to figure this out. In what way is this not “standing by his product?”
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Cris’ clear restatement of the revised standard can be misread as backing away from his own products. But that’s a misreading.

Steve, where in the revision statement does it say ‘for now’? That’s an important difference.
 
Steve Shannon said:
This response baffles me. In what way is this not “standing by his product?”
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Steve Shannon said:
If you’re not sure, you have two choices:
A. See what the manufacturer says in their instructions, or in response to you asking, or
B. Put the mechanical break in the power line.
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​

There is no need to rewrite the documentation if the Quantum works as advertised in the instructions.

Per your choice A:

gavel said:
the igniters are essentially “dead” until you are almost at apogee in flight. The only way you can fire an igniter on the ground is with the test web page, which you cannot get into from the normal Quantum web pages. In addition, the Quantum will not self-arm… if you turn it on with ematches connected it will just sit there with the deployment power turned off until you arm it with your wireless device using the proper validation code.

What this means is that there is an electronic switch on the deployment power, interrupting the circuit and essentially satisfying the NAR/TRA L3 requirement for a switch disconnect on the deployment power until it’s armed. You can connect your battery/batteries with confidence at your work table, knowing that there’s no way to accidentally fire a deployment channel."
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manixFan said:
Nothing in that thread answers my question, your reply is in fact that’s why I asked this question. In that thread you mention "The references include NFPA 1126, which covers the “Standard for the Use of Pyrotechnics Before a Proximate Audience” and NFPA 495, which is entitled “Explosive Materials Code”.

If model rockets are not fireworks, and they are certainly not explosives, was there an affirmative decision to use those codes to regulate our hobby? Or are you saying that because they are largely the same committees that it follows that those rules should be applied to our hobby? Does the board see our ejection charges as being equivalent to commercial fireworks?

I'm just trying to understand why after 20 years of flying HPR, I am just now learning that we should have assumed that rules that apply to commercial fireworks should also apply to us.


Tony
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Okay, I promised to get back to you on this, and I’ll try to explain it better:

If model rockets are not fireworks, and they are certainly not explosives, was there an affirmative decision to use those codes to regulate our hobby?
No - there was no affirmative decision to use fireworks codes to regulate our hobby. Our hobby is not regulated by fireworks codes. Our hobby is regulated by three codes specific to our hobby (NFPA 1122, 1125, and 1127), plus the possibility of local or state codes that may differ in some way. It has always been the responsibility of the flyer to know and understand their local rules.

Or are you saying that because they are largely the same committees that it follows that those rules should be applied to our hobby?
No, because the fireworks rules do not apply to our hobby. But this is closer. Because the same NFPA Pyrotechnics Technical Committee is responsible for both the rocketry codes and the fireworks codes, the rules in both will be similar. For example, the principle that results in a requirement in the fireworks codes to have electric matches physically disconnected from any power sources would also result in a requirement in the rocketry codes to have electric matches physically disconnected from any power source.

Does the board see our ejection charges as being equivalent to commercial fireworks?
No - but many of the same risks are present in both.
 
gavel said:
​

There is no need to rewrite the documentation if the Quantum works as advertised in the instructions.

Per your choice A:
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I understand, now. I had to go back and see what the context was for my post that you included. Evolvent had asked how to know if all power to the device was physically open when using the switch terminals on a device and I said either ask the manufacturer or put the switch in line with the power.
Cris’s document explains why his device prevents an accidental ematch ignition by electronically opening the circuit that runs to the ematch. But Tripoli is requiring a physically open circuit.
 
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Steve Shannon said:
I understand, now. I had to go back and see what the context was for my post that you included. Evolvent had asked how to know if all power to the device was physically open when using the switch terminals on a device and I said either ask the manufacturer or put the switch in line with the power.
Cris’s document explains why his device prevents an accidental ematch ignition by electronically opening the circuit that runs to the ematch. But Tripoli is requiring a physically open circuit.
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This is what I don't understand. What difference does it make if the circuit is electrically or physically opened? Again where is the proof that physical switches are safer if the argument is that we are worried about malfunction of the switching device. I've seen contacts in mechanical switches jam closed..an open circuit is an open circuit. Again in most cases the switch is supplying power to an altimeter which would ALSO have to trip for the charges to fire. Again I'm going to comply with the rules whatever they are but I can't wrap my head around this decision. Im an aircraft mechanic for a commercial airline and almost every single switching failure I've seen in my career has been with mechanical switching
 
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gavel said:
I was not suggesting a rewrite. I was suggesting standing by your product.
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The rule was made by the TRA BoD out of an abundance of caution, honestly to protect them from possible liability in the case of an incident in the future. It has nothing to do with our products, or anyone else's for that matter. I get what they're trying to do... and if it's gonna help us keep our hobby free from any additional regulation then I'm all for it.
 
Does this policy apply to simple (low power) model rocketry?

The NAR MR safety code doesn't address the topic. The TRA has High Power and Research safety codes, explicitly based on NFPA 1127.

I've never seen non-motor charges nor flight computers included in the definition of HPR. 'Wet' rocket mass. Propellant mass. Propellant spark effects. Motor thrust. Motor Impulse.
That's it.
 
Steve Shannon said:
Cris’s document explains why his device prevents an accidental ematch ignition by electronically opening the circuit that runs to the ematch. But Tripoli is requiring a physically open circuit.
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This distinction made by Tripoli is based on a well-meaning but unfounded assumption that opening a circuit with mechanical contacts is superior to opening it with semiconductors.

John Williams said:
This is what I don't understand. What difference does it make if the circuit is electrically or physically opened? Again where is the proof that physical switches are safer if the argument is that we are worried about malfunction of the switching device. I've seen contacts in mechanical switches jam closed..an open circuit is an open circuit. Again in most cases the switch is supplying power to an altimeter which would ALSO have to trip for the charges to fire. Again I'm going to comply with the rules whatever they are but I can't wrap my head around this decision. Im an aircraft mechanic for a commercial airline and almost every single switching failure I've seen in my career has been with mechanical switching
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Bingo.
 
I also feel like this rule change does undue harm to our vendors and developers who work hard to provide our hobby with safe and convenient technology and products. For example I'm not gonna be buying anymore mag switches at 25 bucks a piece if I have to run a mechanical switch also it defeats the whole point. I'm looking for safety and convenience. Once I close that rocket up to go to the rso table I have no desire to open it again. I find prep of electronics and charges to be the most tedious part of high powered rocketry it's also the place I personally feel I am most likely to make a mistake. So in the end of the day that hurts sales for manufacturers like eggtimer and featherweight
 
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Adrian A said:
Now, if "physically open" means open by means of physics, including semiconductor physics, then I'm o.k. with it. :)
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In some cases it is also opened by software. Software is part of the chain.
 
jderimig said:
In some cases it is also opened by software. Software is part of the chain.
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The software may control the semiconductors but the semiconductors are still breaking the circuit. And again aside from a general distrust of computers and electronics I would argue still more reliable than mechanical switching.
 
Steve Shannon said:
This is exactly right. If it were an electromechanical relay but under software control I would have the same concerns.
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Okay but to that point then I could use a mag switch with an electromechanical relay wired into it?
 
Playing devil's advocate again... why is power allowed to be connected to the launch control panel and/or pad boxes while flyers are loading? Particularly for the pad boxes (some of which may be wireless), there is only one "inhibit" in the loop... the device (relay or FET) that powers the igniter. And, they generally are allowed to have a continuity trickle current to the igniters.
 
cerving said:
Playing devil's advocate again... why is power allowed to be connected to the launch control panel and/or pad boxes while flyers are loading? Particularly for the pad boxes (some of which may be wireless), there is only one "inhibit" in the loop... the device (relay or FET) that powers the igniter. And, they generally are allowed to have a continuity trickle current to the igniters.
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I think I can answer this - let's test my understanding:
Yes, there is a risk of the continuity check, an electronic failure, or LCO failure launching the rocket. This is mitigated by:
1) the rocket is supposed to be on the guide, PEU before connecting to the launch system. (I'm told that's a real pet concern of our local prefect.)
2) SOP is to short the leads, looking for signs of energy, before connecting.
3) it's away from the the prep, parking, spectator, and RSO sites.
4) the number of people at the pad is -supposed- to be the minimum to accomplish the task.
 
What about this mag switch with a separate battery for control of a mechanical relay board like the one in this picture. The main battery would be wired to the board and then the board to the altimeter. This provides a mechanical break while still allowing remote control. You would need a separate battery to run the relays It would be risky to enegize a relay coil on your firing battery.. but technically meets the requirements of the rule doesn't it???
 
Relay like this
 

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Charles_McG said:
Cris’ clear restatement of the revised standard can be misread as backing away from his own products. But that’s a misreading.

Steve, where in the revision statement does it say ‘for now’? That’s an important difference.
Click to expand...

I hope that our meetings with the manufacturers will lead to something better defined than simply saying a physical break. We have to consider hardware, software/firmware, and how the devices operate in the absence of power, following a shutdown and restart, both intended and unintended. It doesn’t help that every device works a little or even a lot different.
And, yes, we understand that mischoosing or misusing a physical switch has its own problems also.
 
Charles_McG said:
I think I can answer this - let's test my understanding:
Yes, there is a risk of the continuity check, an electronic failure, or LCO failure launching the rocket. This is mitigated by:
1) the rocket is supposed to be on the guide, PEU before connecting to the launch system. (I'm told that's a real pet concern of our local prefect.)
2) SOP is to short the leads, looking for signs of energy, before connecting.
3) it's away from the the prep, parking, spectator, and RSO sites.
4) the number of people at the pad is -supposed- to be the minimum to accomplish the task.
Click to expand...

Exactly right. It complies with the requirement by being inhibited (by being physically disconnected from the leads) until the rocket is upright and on the pad.
 
Steve Shannon said:
I hope that our meetings with the manufacturers will lead to something better defined than simply saying a physical break. We have to consider hardware, software/firmware, and how the devices operate in the absence of power, following a shutdown and restart, both intended and unintended. It doesn’t help that every device works a little or even a lot different.
And, yes, we understand that mischoosing or misusing a physical switch has its own problems also.
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Not trying to add too much to your plate on this, but could you also address whether both legs of wires to an altimeter need switches in a mechanical switch arrangement? The standard-ish arrangement with one leg connected to the ematches with the other leg switched by the alt has always given me a few heebie-jeebies.
 
John Williams said:
What about this mag switch with a separate battery for control of a mechanical relay board like the one in this picture. The main battery would be wired to the board and then the board to the altimeter. This provides a mechanical break while still allowing remote control. You would need a separate battery to run the relays It would be risky to enegize a relay coil on your firing battery.. but technically meets the requirements of the rule doesn't it???
Click to expand...

Look, I’m not going to participate in “design on the fly” discussions. Once the manufacturers meet with us and we discuss this we’ll all be in a better position to answer.
 
Steve Shannon said:
This is exactly right. If it were an electromechanical relay but under software control I would have the same concerns.
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Even a physical Fred Azinger switch operated by a software controlled servo fits.
 
there are computer controlled launch systems with software controlled silicon switches
 
boatgeek said:
Not trying to add too much to your plate on this, but could you also address whether both legs of wires to an altimeter need switches in a mechanical switch arrangement? The standard-ish arrangement with one leg connected to the ematches with the other leg switched by the alt has always given me a few heebie-jeebies.
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Why in God's name would you switch both legs? Why?....... this feels like we are running into straight up insanity now.
 
cerving said:
Relays don't work very well in rocketry applications. Too much vibration and G forces.
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I'm aware I guess the point I'm making is that something like that would technically meet the requirements of a mechanical break but it is absolutely less safe. For the reasons you stated
 
Steve Shannon said:
Look, I’m not going to participate in “design on the fly” discussions. Once the manufacturers meet with us and we discuss this we’ll all be in a better position to answer.
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Fair enough just trying to work out the options
 
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