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grahamb
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+x+x+x+xYou always need to read the NOTAM briefing, because there are many NOTAM that cannot be graphically depicted.
Having said that, it's usually worth posting about a NOTAM where you think we could have done a better job interpreting the text to draw a more specific illustration than the fail-safe Q-line circle that all NOTAM have. Just like in this thread. Thanks! First thing is a general one, I'd welcome if all NOTAM 'Q-circles' are drawn 2 nautical miles bigger due to the Q-line not using seconds as a geo location. By adding 2 nautical to the radius one would be sure the real affected area of the NOTAM is surely within the circle drawn. Just as a safety add-on to avoid people smashing into closed airspace while they see themselves outside the area. Why 2nm, when the maximum displacement error would be 0.707 nautical miles? If you actually read the NOTAM, there is no issue about 'smashing into' things. Because it is two coordinates and Pythagoras, so up to 1.4nm dislocation. The 2nm was just a suggestion based on add 0.5nm for margin plus no digits after decimal plus keep the safety margin. The trouble with 'smashing into' is not the flight preparation on the ground, but looking at the map in flight and holes in pilots memory to remember the area in question has a different position and in which direction. Gosh, how did we manage when NOTAM were published unfiltered in text form on 10 pages of A4 paper.
0.7 max dislocation, not 1.4. It's only half a mile NS or EW from the centre of a box representing a minute by a minute to the edge of the next one - and that's at the equator.
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pilot-byom
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+xGosh, how did we manage when NOTAM were published unfiltered in text form on 10 pages of A4 paper.
0.7 max dislocation, not 1.4. It's only half a mile NS or EW from the centre of a box representing a minute by a minute to the edge of the next one - and that's at the equator. There is no rule NOTAM Q-lines are mathematically rounded and the one issuing has all the freedom, so they may be off by up to a whole mile and in reality they are sometimes, so it is SQRT(2) max error. Simple risk management, the probability may be low at that distance but the possible impact is high - they will always argue you should have read the full NOTAM, so the display on the map should be max safety, do you agree?
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grahamb
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+x+xGosh, how did we manage when NOTAM were published unfiltered in text form on 10 pages of A4 paper.
0.7 max dislocation, not 1.4. It's only half a mile NS or EW from the centre of a box representing a minute by a minute to the edge of the next one - and that's at the equator. There is no rule NOTAM Q-lines are mathematically rounded and the one issuing has all the freedom, so they may be off by up to a whole mile and in reality they are sometimes, so it is SQRT(2) max. error. I still disagree, but it's not worth arguing about.
However, I disagree with the concept of artifically enlarging the Q-line radius of influence. It's there to draw your attention to a NOTAM, not to define it. The risk is that the less well informed treat the whole thing as a no-fly area, and in areas of congested airspace it can cause people to rereoute their flights and funnel them into narrow spaces unecessarily, or even abandon their flights with the current nervousness about infringements here in the UK currently.
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Tim Dawson
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Actually there is a rule, which is that authorities publish the Q line such that the entire "real" area of the NOTAM is encompassed within the rounded centre and radius, so that radius will always be rounded up (as long as they're doing their jobs properly).
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pilot-byom
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+xActually there is a rule, which is that authorities publish the Q line such that the entire "real" area of the NOTAM is encompassed within the rounded centre and radius, so that radius will always be rounded up (as long as they're doing their jobs properly). As there is no enforcement and even if, no consequences at all, reality is, they don't. Would you be so kind to detail the citable source for such rule? I had several discussions with relevant but stubborn authorities on the issue and it would help me dramatically convincing them to proper work!
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Tim Dawson
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Yes, I will be happy to get this information, and I will ask Eurocontrol directly because firstly it's them that often enforces the rules (they help us get bad NOTAMs corrected on virtually a daily basis) and secondly they have great knowledge of standard practices. It would be helpful if when I ask, I can point to a current NOTAM that does not obey the rules. Can you find one in existence right now?
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Tony N
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+xYes, I will be happy to get this information, and I will ask Eurocontrol directly because firstly it's them that often enforces the rules (they help us get bad NOTAMs corrected on virtually a daily basis) and secondly they have great knowledge of standard practices. It would be helpful if when I ask, I can point to a current NOTAM that does not obey the rules. Can you find one in existence right now? Tim, Have a look at the EGXX NOTAM over Portsmouth harbour. I saw this while flying over there last week and had to read the text a few times (in the air) to convince myself I wasn't about to do anything wrong and infringe.... I can't quite figure out if this should be a NOTAM or not, especially if it is going to remain depicted for nearly another three months. Tony
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Tim Dawson
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After reading that NOTAM twice I've still no idea what it's about, really. It's impossible to comment on the accuracy of its radius because it doesn't specify a more precise one in the body of its text.
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riverrock
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When there are coordinates in NOTAMS you do a great job of depicting the actual area being NOTAMed however the influence ring is still depicted. There appears to be no information about the red ring available when you press on the area, only within the coordinates of the effected area. Could I suggest that if the red ring is still shown that it should still be possible to press and hold within it to see the NOTAM? Alternatively, don't show the red ring.
Thanks!
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