wilkersk
Pattern Altitude
But, you notice its when both runways have RIGHT traffic. Using Traffic indicators for standard LEFT patterns is superfluous and leads to discussions like this one.
Flying straight in at uncontrolled field?
- Thread starter CC268
- Start date
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
I suppose they should revise it, but don't follow the second part of your argument. The reason for the direction of the traffic pattern is immaterial to how to interpret the traffic pattern indicators.
Real problem is the FAA seems to have developed a system that is broken. Better to get rid of it. It's 2017, if you can't figure out the traffic pattern direction before you get to the airport, you have bigger problems.
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
Most of the arguments the opponents put forth against the AFH drawing would be the same if the image was flipped such that both runways were both right traffic. I'm pretty sure we would still be having this discussion if that was the case.
dtuuri
Final Approach
Not in my case. Now that I know that there is at least one runway in the U. S. with right traffic specified for both base legs, the only remaining issue is that the diagram in the AFH shows LEFT traffic for both ends, and a pattern indicator like that would be unnecessary.
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
Trying to come up with frivilous arguments? If they revise it they can erase the "populated area or hazard". The AC is not intended to describe a procedure for designing patterns that avoid populated areas.
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
Doesn't really seem important. The point of the image is to teach people how to read the symbols, so why not show what standard left traffic would look like for that purpose?
I'm not saying it's a huge deal, but I think it should be shown in a configuration that a pilot might actually see somewhere. One could also argue that it should be shown in the configuration that a pilot is most likely to see.
Last edited:
What is your source for that statement? I admit I could have overlooked it, but I'm not seeing any such limitation of scope in the AC itself.
I can also tell you that avoiding population areas is the ONLY reason that my home airport has a pattern direction indicator.
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
"This advisory circular (AC) sets forth standards for a system of airport marking consisting of certain pilot aids and traffic control devices."
It says how to indicate the direction of the traffic pattern. It says nothing about which direction of traffic pattern an airport should establish or why.
dtuuri
Final Approach
I'm still stunned that such a longstanding meaning can be changed with no fanfare in books already-licensed pilots aren't likely to study. The current AIM still has the passage I quoted earlier from my archived copy of the PHAK:
5. Traffic pattern indicators.
...If the pilot will mentally enlarge the indicator for the runway to be used, the base and final approach legs of the traffic pattern to be flown immediately become
apparent. Similar treatment of the indicator at the departure end of the runway will clearly indicate the direction of turn after takeoff.
So, I say the AIM is right, the PHAK and AFH are wrong until and unless the AIM is revised. I find that swastika very confusing and in 50+ years I've never seen one. As for Friday Harbor, I'm skeptical. Show me the noise study.
dtuuri
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
Why bother quoting my post if you aren't going to rebut it?
The underlined passage cannot be right because it presents a paradox in situations such as Friday Harbor.
What are you skeptical of?
dtuuri
Final Approach
I started to, then changed my mind and went in a different direction.
"Trying to come up with frivilous arguments?"
No.
"If they revise it they can erase the 'populated area or hazard'."That would look like there's no purpose at all.
"The AC is not intended to describe a procedure for designing patterns that avoid populated areas."Hazards as well as populated areas--it's in the diagram.
"The underlined passage cannot be right because it presents a paradox in situations such as Friday Harbor."Friday Harbor is so unique, if it is even justified, those circumstances deserve a special treatment:
dtuuri
Attachments
Last edited:
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
1. Yes you are.
2. The purpose is to describe how traffic pattern directions are indicated by the airport to the pilot. The purpose is not to explain why the airport has selected that direction. IT DOES NOT MATTER.
3. I chose to leave out the word "hazards" for brevity. What is your point? You have none.
4. That's not any kind of accepted traffic pattern at all. You criticized such a pattern before, but now you advocate it?
Last edited:
It seems awfully nit-picky to me if you're saying that they shouldn't include an example on the diagram of why someone might want to have a non-standard pattern. I don't see how it detracts in any way from accomplishing the stated purpose as you quoted it.
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
No, that's not what I'm saying. My point is that the argument in post 204 is frivolous. If a diagram of a situation like Friday Harbor's would look silly, they can change it so that it doesn't look silly.
dtuuri
Final Approach
Swastikas look silly. I, for one have always interpreted the departure leg when looking at a segmented circle, not a base leg, and I've done so i/a/w the published guidance--for over 50 years! To have that up and changed without explanation in a reference for students offends me. I also don't like having all these right-hand non-standard patterns for "noise", which is putting safety below comfort. I want better reasons for the need, besides just more timely notification, in a more appropriate source. The AIM should lead the way, not follow a rogue textbook.
dtuuri
eetrojan
Pattern Altitude
I don't follow the logic. Doesn't it make sense to have a traffic pattern indicator even for the standard situation of left turns? i.e. so finding it confirms the field is standard and you don't have the nagging feeling you didn't find the traffic pattern indicator?
Last edited:
tspear
En-Route
- Joined
- Dec 10, 2010
- Messages
- 3,587
- Display Name
Display name:
Timothy
I have only been flying for a decade. I was taught the indication was always base leg. Reason is simple, you view it from above as you are coming in to land. You cannot see the indications on the ground unless you walk over and stand on it.
Being a good neighbor is allowing for the noise factor. Regardless of the fact that many lawn mowers are louder, it is the specific pitch and doppler effects which make planes stand out. As such, pilots who only know how to turn left are discourteous and can cause unnecessary issues for other pilots.
Tim
eetrojan
Pattern Altitude
Hi Dave - Just FYI, here's another. This one is at KRNM (Ramona Airport) in SoCal. It was the destination for my first student solo which is why I looked it up:
I don't have all that much experience and may well be wrong, but if I were doing "closed traffic" pattern work at this airport when tower was closed, then after takeoff/departure, I would simply turn left crosswind to fly my downwind on the side that resulted in me making left traffic to land.
If the wind favored RWY 27, my pattern work would be on the south side. If the wind favored RWY 9, my pattern work would be on the north side. That of course, is based on my interpretation of this traffic pattern indicator.
Notwithstanding that AIM figure 4-3-2 you reference above, it wouldn't even dawn on me that I should consider turning right after takeoff.
Last edited:
eetrojan
Pattern Altitude
Same here on having been taught that the indication relates to required turn direction for the base leg as opposed to required turn direction for departure.
I've never heard it stated like this, but that sure sounds logical and correct to me.
And that one depicts the standard left traffic, exactly as shown in the AFH!Hi Dave - Just FYI, here's another. This one is at KRNM (Ramona Airport) in SoCal. It was the destination for my first student solo which is why I looked it up:
I don't have all that much experience and may well be wrong, but if I were doing "closed traffic" pattern work at this airport when tower was closed, then after takeoff/departure, I would simply turn left crosswind to fly my downwind on the side that resulted in me making left traffic to land.
If the wind favored RWY 27, my pattern work would be on the south side. If the wind favored RWY 9, my pattern work would be on the north side. That of course, is based on my interpretation of this traffic pattern indicator.
Notwithstanding that AIM figure 4-3-2 you reference above, it wouldn't even dawn on me that I should consider turning right.
dtuuri
Final Approach
Right, and which is specifically NOT TO BE SHOWN, as stated in FAA's capital letters in AC 150/5340-5D. I think we have some rogue airport managers running amok out there on the left coast.
dtuuri
Last edited:
dtuuri
Final Approach
First of all, nice work finding that. As for how I mentally interpret the pattern indicator (remember it's in perfect compliance with the current AIM and has been for half a century), I like to start at the beginning and finish at the end--which means I start at the takeoff.
dtuuri
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
14 CFR 91.126 does not regulate the direction of turns for departure. Only arrival. So there is no need to indicate departure turns, just like there is no need to indicate traffic pattern altitude, which is advisory, not regulatory.
dtuuri
Final Approach
Don't you have something better to do, like, say, texting while driving? I find the direction of turns in the pattern in reference to the first turn, not the last one. They both go the same way and the AIM tells me I can do it that way and I'm sure others do too and it's been that way since forever and changing it all by publishing the change in a student manual instead of the AIM is a lousy thing. Over and out.
dtuuri
eetrojan
Pattern Altitude
Hi Dave, I think I figured it out. It's just a matter of adjusting your viewpoint.
In your Monday post, you said:
And, you annotated the figure like this:
Respectfully, however, I think your misinterpreting this diagram. I don't believe the circled indicator means you should make a right turn when landing and a left turn when departing.
Instead, I believe the diagram should be interpreted more like this, where the red indicator specifies the red pattern (all right turns) and the green indicator specifies the green pattern (all left turns):
In my crazy mind, it's like each pattern indicator independently "pulls" the planes around the pattern to the approach end of the runway associated with that indicator.
I don't believe the traffic pattern indicators are meant to signal a required or even preferred departure direction, ignoring the practicality of both patterns being on one side of the runway, as in this figure, in consideration of traffic for other runways at the same field, the presence of terrain or noise sensitive neighbors on the other side, etc.
Thoughts?
Last edited:
That's what I usually say, sometimes maybe the distance.
JAMES B. BUSEY, Administrator, Federal Aviation Administration, Complainant, v. KENNETH S. RIVARD, Respondent. This case in turn relies on Administrator v. Dibble. Ironically, the guy they busted in Dibble made a right turn to final, thereby interfering with another aircraft that was already on a straight in approach.
There are two actions involving that respondent that show up using the NTSB search tool, but neither contains the quote in question. Maybe it's from the appeals court case referred to in the NTSB's stay order.
dtuuri
Final Approach
Thank you for clearly illustrating your point with a drawing. I wish more folks took the time to do that.Hi Dave, I think I figured it out. It's just a matter of adjusting your viewpoint.
In your Monday post, you said:
And, you annotated the figure like this:
Respectfully, however, I think your misinterpreting this diagram. I don't believe the circled indicator means you should make a right turn when landing and a left turn when departing.
Instead, I believe the diagram should be interpreted more like this, where the red indicator specifies the red pattern (all right turns) and the green indicator specifies the green pattern (all left turns):
In my crazy mind, it's like each pattern indicator independently "pulls" the planes around the pattern to the approach end of the runway associated with that indicator.
I don't believe the traffic pattern indicators are meant to signal a required or even preferred departure direction, ignoring the practicality of both patterns being on one side of the runway, as in this figure, in consideration of traffic for other runways at the same field, the presence of terrain or noise sensitive neighbors on the other side, etc.
Thoughts?
The way you drew the colored arrows is exactly how I've always interpreted the pattern indicators, with one exception. The indicator colors on top and bottom of the segmented circle are reversed for me. I don't like having "my" method fussed with in a student manual and then having the "students" tell me how wrong I am when it's as legitimate as "their" way according to the AIM. In fact, I think BOTH ends of the landing strip/pattern indicators are intended to show each end of the pattern, that's why there's a requirement to have them laid out in "pairs" not singularly. I suspect some airport managers are going a bridge too far by making both patterns non-standard by flipping one of the required pair. I doubt that possibility was ever considered back when this system began and probably isn't needed at all.
dtuuri
1991 NTSB LEXIS 200 (Order No. EA-3413; Docket SE-9445)
dtuuri
Final Approach
Here's a better explanation of my viewpoint. The pattern indicators are meant, imo, to show the corners of the pattern:
azure
Final Approach
???D'oh...yes of course, it is 12 and 31. I meant 31 but wrote 30. No, nothing to do with nearness to thenorthpole
I'm really puzzled by what your drawing is showing. Can you elaborate?
I deleted the post you were replying to because I felt I was derailing this thread which has its own impetus. I'll still keep checking here anyway so I will see any answer you give. Thanks!
12 and 30 are reciprocals, 13 and 31 are reciprocals. 12 and 31 are not.
Requires a password.
eetrojan
Pattern Altitude
Hi Dave,
I absolutely see what you’re thinking. In fact, I make this same mental picture.
Still, I suspect our mental image works because the two indicators point to the same side almost all the time, by coincidence, rather than because the FAA intended the indicators be used together in pairs.
In fact, at 4-3-4c, the AIM says “pilots should concern themselves with the indicator for the approach end of the runway to be used,” further noting that “if the pilot will mentally enlarge the indicator for the runway to be used, the base and final approach legs of the traffic pattern to be flown immediately become apparent.”
In other words, without the need to know anything about the other indicator, if you start with the indicator for the approach end of the runway, you can “mentally enlarge” it all the way around the pattern to roll out the various legs in your mind's eye, something like this:
The AIM's next sentence is admittedly supportive of your viewpoint because it says, "Similar treatment of the indicator at the departure end of the runway will clearly indicate the direction of turn after takeoff," but I bet the authors were still talking about "mental enlargement" of the approach end indicator, all the way around to the departure end, to let you know which direction to turn, not that you should literally take the other indicator into account.
It’s more satisfying to me that "mentally enlarging" one indicator accommodates all four of the possible combinations:
We’re probably dancing on the head of a pin by this point because Scenario A is standard left turns and often not indicated because it's not required to be, and Scenario D is really rare.
Anyway, just food for thought.
dtuuri
Final Approach
I'm glad you've taken an interest in this. I always like to try to understand the minds of the originators of our rules rather than 'late to the party' interpreters. So, I've gone back to a 1961 book on Civil Air Regulations, a predecessor of the FAR/AIM, and it explains that the vertical part of the "L" indicates the turn for landing and the base part of the "L" shows the turn after takeoff. So, your theory is not correct, imho, applied to how things were supposed to be and still supported in the AIM, albeit they did improve that rather contorted explanation sometime later.Hi Dave,
I absolutely see what you’re thinking. In fact, I make this same mental picture.
Still, I suspect our mental image works because the two indicators point to the same side almost all the time, by coincidence, rather than because the FAA intended the indicators be used together in pairs.
In fact, at 4-3-4c, the AIM says “pilots should concern themselves with the indicator for the approach end of the runway to be used,” further noting that “if the pilot will mentally enlarge the indicator for the runway to be used, the base and final approach legs of the traffic pattern to be flown immediately become apparent.”
In other words, without the need to know anything about the other indicator, if you start with the indicator for the approach end of the runway, you can “mentally enlarge” it all the way around the pattern to roll out the various legs in your mind's eye, something like this:
The AIM's next sentence is admittedly supportive of your viewpoint because it says, "Similar treatment of the indicator at the departure end of the runway will clearly indicate the direction of turn after takeoff," but I bet the authors were still talking about "mental enlargement" of the approach end indicator, all the way around to the departure end, to let you know which direction to turn, not that you should literally take the other indicator into account.
It’s more satisfying to me that "mentally enlarging" one indicator accommodates all four of the possible combinations:
We’re probably dancing on the head of a pin by this point because Scenario A is standard left turns and often not indicated because it's not required to be, and Scenario D is really rare.
Anyway, just food for thought.
The Advisory Circular mandates that there are "pairs" of traffic indicators, i.e., two each, for every right-hand pattern and zero for left-hand patterns. It's obvious they weren't intending for anyone to have two right-hand patterns for the same runway given the original explanation about the vertical and base parts of the "L". While flipping one end might seem a clever way, even an economical way to accomplish the job, assuming there's merit in having two right-hand patterns for the same runway, it looks quite confusing to someone like me who tries to get the bigger picture. I would rather see a new symbol for this rare "inverse" of a no-symbol left-hand pattern than mucking up a long-time recognized method of indicating the side of the runway where all the action should stay.
dtuuri
I am unable to decipher that explanation.
dmspilot
Final Approach
- Joined
- Oct 20, 2006
- Messages
- 6,169
- Display Name
Display name:
DISPLAY NAME
That AC is self-contradictory. If runway 36 has a left pattern and runway 18 has a right pattern how can you mandate that the indicators come in pairs and also mandate that left-hand patterns are not shown?
I'll say it again. Your explanation of how they're supposed to be interpreted results in a paradox.
Last edited:
dtuuri
Final Approach
Others probably thought that too, so they changed it to how it is now in the AIM. But here's what it's saying:
