What is triple mix for INS?

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jonvcaples said:
Also the DC-10 training materials did not cover triple mix either. It was mentioned as a function of the system but not explained or expounded upon in any of our material. The International Ops course mentioned it but did not explain it. Kind of like most pilot training doesn't really explain how transponders, VOR and or DME work except in very high level non-technical language.
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I'm typed on the 757/767. I certainly remember the discussion on IRS and the various modes it operated in.

In your resume on the internet it shows you were a DC-10 Program Maintenance Coordinator during 91-96. I know that the DC-10 MM's did have detailed breakdown of the functions of the INS systems installed, and went into further detail than the FOM. Certainly as a PMC you had access to the manuals, right?


jonvcaples said:
I'll humor your silly game a little bit with three questions.

1-What modulation is used for aircraft voice communications?
2-Why?
3-Why are their only 4,096 transponder codes?
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Which have zero to do with the discussion at hand. BTW, those 3 questions can be answered with a quick google search, so what's your point?
 
EdFred-Congrats, ya nailed it!

Caramon13-Thanks for the references!

Doc-I "yelled" because you were not and apparently continue to not grasp that while I was a UAL there was nothing in any of the material to which I had ready access that discussed triple mix. It was not discussed just as many topics are not discussed beyond the simplest position the switch, observe the reading, react accordingly. The 757/767 fleet was the first to only teach aircrew what they needed to safely operate the aircraft. Up until that point most fleets had taken the old school you need to be able to build or fix the thing approach. Take electrical systems. That fleet did not talk about frequencies, phasing, volts, or amps. Why? Because pilot's didn't need to know that to operate the aircraft! With Boeing's quiet cockpit approach and some 400 plus microprocessors controlling everything the system was good (no cautions, warnings etc.), some microprocessor made it good, or you had a switch or other device to tell you something was out of limits. Pilots had no way to parallel the generators (former 727 plumbers LOVED this).

Over the years I've performed tons of google searches on triple mix and never found a detailed explanation of it. The prior searches only found results that said it existed and was a tool for refining positional data. Several recent posts on here have turned up great refernces that will be reviewed as time permits.

Many of your posts are relevant and helpful. Others you seem to just want to be snarky, insulting, and demeaning. I for one would appreciate you sticking to the relevant and helpful. Can we agree to this?
 
I’ll humor this silly game. How many squawk combinations can be transmitted on a Mode 4 transponder? Learning is fun!
 
Doc, no I did not have access to the DC-10 maintenance manual...well I guess if my boss would have approved it a several day trip to Chicago to visit our maintenance department could have been arranged.

And no I did not have access to a complete FOM. Everything we taught at the training center had to be tied to the contents of the airplane specific Training Manual. These manuals were developed using the FOM but winnowed down to the information necessary to operate the aircraft not build or maintain it.

Those 3 questions were intended to encourage thinking about what and how we educate pilots. Sure it is easy to google the answers. But that is why I asked the 2nd question. The answer to question 1 is Amplitude Modulation (AM). The answer to the 2nd involves understanding fundamentals of radio communication. With AM when two transmitters are on the same frequency and within range of a receiver the receiver will hear a squeal or hum so they know they did not receive the transmission. When this happens using FM the receiver usually hears only the stringer signal and may not be aware someone else is trying to communicate with them.

4,096 is the number of combinations possible with a 4 digit octal (base 8) number as someone already pointed out.

Does this make sense? My goal is to encourage thought and curiosity in a civil, productive manner.
 
jonvcaples said:
EdFred-Congrats, ya nailed it!

Caramon13-Thanks for the references!

Doc-I "yelled" because you were not and apparently continue to not grasp that while I was a UAL there was nothing in any of the material to which I had ready access that discussed triple mix. It was not discussed just as many topics are not discussed beyond the simplest position the switch, observe the reading, react accordingly. The 757/767 fleet was the first to only teach aircrew what they needed to safely operate the aircraft. Up until that point most fleets had taken the old school you need to be able to build or fix the thing approach. Take electrical systems. That fleet did not talk about frequencies, phasing, volts, or amps. Why? Because pilot's didn't need to know that to operate the aircraft! With Boeing's quiet cockpit approach and some 400 plus microprocessors controlling everything the system was good (no cautions, warnings etc.), some microprocessor made it good, or you had a switch or other device to tell you something was out of limits. Pilots had no way to parallel the generators (former 727 plumbers LOVED this).

Over the years I've performed tons of google searches on triple mix and never found a detailed explanation of it. The prior searches only found results that said it existed and was a tool for refining positional data. Several recent posts on here have turned up great refernces that will be reviewed as time permits.
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I find it odd that the information has never been hidden, and anyone with just a bit of intuition could find it. Again, for someone who claims they were a systems instructor on the 757/767, you taught this without knowing how it worked? Did you just read from the slides? The instructors I'm familiar with knew the airframe inside and out, and would often go to the MM's to get a detailed description of a system in order to teach it more effectively.


jonvcaples said:
Many of your posts are relevant and helpful. Others you seem to just want to be snarky, insulting, and demeaning. I for one would appreciate you sticking to the relevant and helpful. Can we agree to this?
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Perhaps you could heed your own advice? How many of your postings go off on a tangent that has zero to do with the thread?
 
Velocity not sure if that information is available. If memory serves me well Mode 4 is a secure system used by the military. Is that information available in open sources?

If you have and can share the answer please do!
 
Doc last time...never said the information was hidden I did say that I could not find it,,,the Boeing fleet at UAL used LRGs and never even mentioned triple mix. We did cover that you needed to turn them on early (2nd or 3rd time in start flow) because they required 15 minutes to align (couldn't move airplane during alignment) and that pilots needed to check and verify insertion of proper lat/lng data. If a LRG LRU did not agree with the entered position problems could and did arise (KAL007). Common reason for system not agreeing with entered position was the aircraft had been moved (think it was more than a mile from shutdown point) such as would happen if towed to gate from maintenance or LRG was swapped in to replace one removed for maintenance.

Freely admit to wandering around in thoughts and words.
 
jonvcaples said:
the Boeing fleet at UAL used LRGs and never even mentioned triple mix.
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LRG"s ?? LRU?? I'm curious, where are you getting these abbreviations from? They're certainly not Boeing. LRG?? I know what a RLG is, but never heard it referred to as a LRG. Also, in Boeing (and other manufactures), LRU stands for "Line Replaceable Unit". Not sure what you think it means.

jonvcaples said:
If a LRG LRU did not agree with the entered position problems could and did arise (KAL007).
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Well, besides the dubious abbreviations being used, this had nothing to do with KAL007. Suggest you go read up on cause and analysis of KAL007.

My point in all of this, you claim to have taught aircraft systems on the B757 at a major airline, however you can't recall system abbreviations and you seem to be lacking basic system knowledge of the aircraft. You even claim you did all of the training for a type rating on the aircraft right up to the check ride.

Forgive me if I seem suspect of what's been claimed, but things are not adding up here.
 
LRG-Laser Ring Gyro LRU-Line Replaceable Unit At UAL we also didn't teach how the gyros work nor the language used to program the flight control computers. We did teach there are 3 FCCs and SOP was to engage the center one. It has been a long time ago so I don't remember exactly why this was the case vaguely recall it had something to do with the Autoland system and crosschecking between the FCCs and FMS. And things such as the ASA tells you what you can't do before it tells you what you can do. Argue all you want but I was there, you were not.

The 727 folks had a really hard time with the just teach them what they need to safely fly and operate the airplane philosophy. After decades of having to know every nut, bolt, and tons of extraneous details they frequently complained we were not teaching them enough. Other things such as the type of hydraulic fluid and pressure in the system, were not taught. When they came back for their first PC they were very apologetic and really appreciated the new approach.

One of the 727 oral questions had to do with if some bus failed could you read the HSI? The follow on question was could you believe the course deviation displayed? WTF? Some of the instructors and check airmen considered this series of questions to be good because answering them required very detailed knowledge of the electrical and nav systems. I thought the first question was acceptable, but only to see if the answer included the fact it would cause the display to spin, whereas the 2nd was was totally absurd. We (757 fleet) had several check airmen transfer back to the 727 because they would not accept the know how to operate versus how to build/maintain approach.

Maybe I'm confusing things but wasn't KAL007 the 747 that was shot down by Russia after straying into Russian airspace because the crew entered wrong coordinates? Perhaps not the best illustration for my point.
 
jonvcaples said:
LRG-Laser Ring Gyro LRU-Line Replaceable Unit At UAL we also didn't teach how the gyros work nor the language used to program the flight control computers. We did teach there are 3 FCCs and SOP was to engage the center one.
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Again, you’re using bogus abbreviations. Anyone who was trained on the equipment would use correct terminology. As a CFI you should know this. As a supposed systems instructor you should know this. Systems Instructors, as well as Sim Instructors and Check Airmen/APD’s would not accept terminology that is incorrect as it shows the applicant has not attempted to read and assimilate the FOM.

Even the systems test used correct terminology.

jonvcaples said:
It has been a long time ago so I don't remember exactly why this was the case vaguely recall it had something to do with the Autoland system and crosschecking between the FCCs and FMS. And things such as the ASA tells you what you can't do before it tells you what you can do. Argue all you want but I was there, you were not.
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You may have been there, but I have the actual types and experience and I’m very aware of what training involved on this airframe. You obviously don’t, and it’s evident in your replies.

jonvcaples said:
The 727 folks had a really hard time with the just teach them what they need to safely fly and operate the airplane philosophy. After decades of having to know every nut, bolt, and tons of extraneous details they frequently complained we were not teaching them enough. Other things such as the type of hydraulic fluid and pressure in the system, were not taught. When they came back for their first PC they were very apologetic and really appreciated the new approach.

One of the 727 oral questions had to do with if some bus failed could you read the HSI? The follow on question was could you believe the course deviation displayed? WTF? Some of the instructors and check airmen considered this series of questions to be good because answering them required very detailed knowledge of the electrical and nav systems. I thought the first question was acceptable, but only to see if the answer included the fact it would cause the display to spin, whereas the 2nd was was totally absurd.
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I’m typed on the 727 as well. Again, you’re rambling about a subject you know nothing of.

jonvcaples said:
We (757 fleet) had several check airmen transfer back to the 727 because they would not accept the know how to operate versus how to build/maintain approach.
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Not sure what this has to do with your lack of knowledge on what you claimed to have been an instructor on.

jonvcaples said:
Maybe I'm confusing things but wasn't KAL007 the 747 that was shot down by Russia after straying into Russian airspace because the crew entered wrong coordinates? Perhaps not the best illustration for my point.
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Again, go read the actual report. It’s easy to find.
 
I could offer up copies of my pay statements but I didn't keep any. Or I could hunt for some of the folks I worked with but frankly I doubt you would believe them either. Doc seems like your mind is made up and nothing is going to change it so I'm done with this discussion. I know what I did and am not interested in arguing, debating, or whatever with you about this any further. Feel free to harangue away but don't look for any responses.
 
jonvcaples said:
We did teach there are 3 FCCs and SOP was to engage the center one. It has been a long time ago so I don't remember exactly why this was the case vaguely recall it had something to do with the Autoland system and crosschecking between the FCCs and FMS.
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The 757/767 has three separate sets of data inputs, data processing, and data outputs. The left flight instruments, flight control computer, flight director, autopilot, etc. are all using the left data and computers. Right uses right. Center uses center. If there's anything wrong in the process of either the left or right systems it will show up on the respective side displays or autopilot actions. There are no displays of the center data so the only way to know if something is wrong is if the center autopilot is in CMD (engaged).

When an ILS is coupled (1,500' RA?) the three systems, as well as hydraulics for flight controls and the electrical bus systems, all isolate. All three autopilot systems, A, B, and C, engage. This configuration is maintained throughout an autoland. If you weren't engaging Center CMD each flight you wouldn't know you had a problem until you started an ILS.

If a problem does develop somewhere in the Center system, you would switch to either Left or Right CMD and would continue but would have lost your LAND 3 capability.
 
To answer the other two questions:
1-AM (Amplitude Modulation)
2-Because a receiver listening to two transmitters on the same frequency will hear a buzz or other sound letting them know two stations are transmitting at the same time. FM (Frequency Modulation) penetrates wx better but in the scenario under discussion the receiver will hear only the stronger signal. So they would not be aware of the 2nd transmitter.

Last comment on 757 and triple mix...we used to joke about the Fr Guido Sarducci (old SNL routine) 757 ground school. 2, 3, the center one, the other one, 1,500 ft, 200 ft, 80 knots, and Progress Page 2. Explanation when the Standards Captain asks during your oral:
How many XYZ's are installed? 2 or 3
Where is the alternate xyz? If there are only 2 obviously the other one. If there's 3 it is the center one.
1,500 feet RA autoland self test starts.
200 feet the center system locks and if a failure in part of the Autoland System occurs you still see LAND 3 because it is considered safer to continue the landing.
80 KIAS is where most things arm or disarm.
Progress Page 2 is the only place to find TAS.
 
jonvcaples said:
To answer the other two questions:
1-AM (Amplitude Modulation)
2-Because a receiver listening to two transmitters on the same frequency will hear a buzz or other sound letting them know two stations are transmitting at the same time. FM (Frequency Modulation) penetrates wx better but in the scenario under discussion the receiver will hear only the stronger signal. So they would not be aware of the 2nd transmitter.
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jkeELOD.jpg



jonvcaples said:
Last comment on 757 and triple mix...we used to joke about the Fr Guido Sarducci (old SNL routine) 757 ground school. 2, 3, the center one, the other one, 1,500 ft, 200 ft, 80 knots, and Progress Page 2. Explanation when the Standards Captain asks during your oral:
How many XYZ's are installed? 2 or 3
Where is the alternate xyz? If there are only 2 obviously the other one. If there's 3 it is the center one.
1,500 feet RA autoland self test starts.
200 feet the center system locks and if a failure in part of the Autoland System occurs you still see LAND 3 because it is considered safer to continue the landing.
80 KIAS is where most things arm or disarm.
Progress Page 2 is the only place to find TAS.
Click to expand...

the-wisdom-of-cheers-cliff-clavin-thechive-lovable-quotes-creative-0.jpg
 
Doc I find your behaviour odd. You hide behind an avatar based on a gunslinger card shark who died of syphilis and tuberculosis.

I have never hidden my name and will gladly accept being compared to Norm who is not the brightest bulb in the chandelier but was a kind hearted, caring person who would give you the shirt off his back if you needed it.

Flame on and keep showing what a low life you are.
 
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