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A dangerous magenta line?

flightlogic

flightlogic

Well Known Member
Patron
Reading another thread this morning about losing the magenta line brought a topic to mind. I live and fly in the airspace filled with students from a major university. Having done it myself, I know that mixing up my cruise altitude rules can happen. I suppose it happens now and then with the students near me who have grown up with the magenta line.
Deliberately flying offset from a point to point gps magenta line might be something worth considering these days. The precision we navigate with has a hidden risk. Oncoming traffic, also following the line, but at the wrong altitude might come nose to nose at high speed. I often fly direct... but after maneuvering on departure, set a new direct course line. In this case, the lines should never merge... since a randomness has been introduced. If, on the other hand, you create an airport to airport direct to destination... you will be precisely on a course that others may be flying as well. Only the altitude keeps you apart. And even that does not solve climbs and descents. Trio autopilots have a feature called TOP. Track offset position. A user can easily fly along side the magenta course but track it. Other autopilots incorporate the same concept. Food for thought this morning and I welcome any comments or contradictions RVers might offer.
 
flightlogic said:
Reading another thread this morning about losing the magenta line brought a topic to mind. I live and fly in the airspace filled with students from a major university. Having done it myself, I know that mixing up my cruise altitude rules can happen. I suppose it happens now and then with the students near me who have grown up with the magenta line.
Deliberately flying offset from a point to point gps magenta line might be something worth considering these days. The precision we navigate with has a hidden risk. Oncoming traffic, also following the line, but at the wrong altitude might come nose to nose at high speed. I often fly direct... but after maneuvering on departure, set a new direct course line. In this case, the lines should never merge... since a randomness has been introduced. If, on the other hand, you create an airport to airport direct to destination... you will be precisely on a course that others may be flying as well. Only the altitude keeps you apart. And even that does not solve climbs and descents. Trio autopilots have a feature called TOP. Track offset position. A user can easily fly along side the magenta course but track it. Other autopilots incorporate the same concept. Food for thought this morning and I welcome any comments or contradictions RVers might offer.
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I don't think it's a terrible idea, but if you're flying direct from airport A to airport B my guess is that the chance of Airplane B flying the opposite route at your altitude is slim. I think your technique certainly has validity while flying along airways. Remember GOL Flight 1907 in Brazil?

One thing I tend to do is cruise slightly higher/lower than being right on. For example, heading east at 7,500 ft, I usually like to be at 7,400 or 7,600.

Of course these techniques don't replace the Mark I eyeball. Keep up a good scan!
 
When I hand fly, I look outside most of the time. Then, a glance inside shows I've drifted off course. Rather than get back on the magenta line, I just push the 'direct' button to reset the course. So on a typical flight I 'randomize' my course multiple times! Now the autopilot is another story...
 
An ADS-B system, if you have the full system with ADS-B out, is an eye-opener. Numerous times I've found myself converging within a mile of another plane on a completely different track. And frequently I can't locate the small target visually even when I know where to look. After installing an ADS-B system I keep my head on a swivel and eyeballs outside even more. I didn't know what I was missing.

Then there were the six buzzards in the pattern at Mexia the other day. My GPS track shows a bit of weaving for that approach.
 
good replies

I like Bob's approach to the line. If you wander off... just reset the line by pushing Direct To. The randomness is good. Also, the comment of flying slightly off altitude helps. In the near misses I have had at Oshkosh being a manufacturer demo pilot... I found pitching up or down is better than trying to initiate a turn for collision avoidance. A small altitude change is all that is needed in most cases.
 
The ADB-S Curse

Since installing ADB-S, I see every boogie on the screen. Many that come close, I do not see regardless of where I look.

So, the positive of ADB-S is I see every boogie, the negative I cannot see every boogie, even those that have become yellow balloons!

I wouldn't do away with it, but it can be unnerving at times! Relative distance to a boogie would be useful (or maybe not!)
 
chazking said:
Since installing ADB-S, I see every boogie on the screen. Many that come close, I do not see regardless of where I look.

So, the positive of ADB-S is I see every boogie, the negative I cannot see every boogie, even those that have become yellow balloons!

I wouldn't do away with it, but it can be unnerving at times! Relative distance to a boogie would be useful (or maybe not!)
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Sometimes they don't have to be far away. One day coming in to Huntsville, AL I was talking to the tower they vectored me on crosswind right off business end the active runway. He says I have traffic just off the runway- a DC9, I can not see it!! I did when he turned out to his left and showed me some (aluminum) skin. Pointed right at me it was lost to me, nothing moving. ADS-B would be a welcome tool for that condition. Flashing lights would help too.
 
Airlines do this

As a 30-year veteran international airline pilot, I can say that ever since we started navigating with GPS more than VORs, we soon discovered the danger that it's precise accuracy presents; an increased chance of head-on collisions.
It is SOP for us to offset 1, or 2 miles from the magenta line while on North Atlantic tracks, and is an accepted technique to do the same when operating in "less-than-perfect" radar environments?aka South America and similar airspace. Especially in airspace that has not totally embraced the TCAS requirements.:p
 
I've thought of installing a small smoke system for those times when I need to be seen. Large planes are hard to see, and my RV-3 is practically invisible from a mile away.
 
Only 25 years in but same same. :)
Its called SLOP. Strategic Lateral Offset Procedure. Always to the right, and out on the tracks (over the ocean) it doesn't require permission. I do it domestically as well whenever we fly an airway (which is almost never anymore. We are always filed point to point) With GPS accuracy being what it is, even 1/2 mile will do the trick.
I think it's a good idea... especially around Prescott. Flew BE-1900's in there many years ago, (pre TCAS) and it was... "exciting":eek:

DM

AAflyer said:
As a 30-year veteran international airline pilot, I can say that ever since we started navigating with GPS more than VORs, we soon discovered the danger that it's precise accuracy presents; an increased chance of head-on collisions.
It is SOP for us to offset 1, or 2 miles from the magenta line while on North Atlantic tracks, and is an accepted technique to do the same when operating in "less-than-perfect" radar environments…aka South America and similar airspace. Especially in airspace that has not totally embraced the TCAS requirements.:p
Click to expand...
 
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