narrow route briefing shape

[18greens]

Does anyone know if its an oblong or a lozenge? Ie does it include the 10 miles beyond the destination airfield or does it assume you don't go beyond the destination?

[chrisN]

It's a rectangle and does not go beyond the destination. So in theory if you do a circuit that includes the other side, you are into unknown territory. Ditto at the start airfield.

Activities at the aerodromes themselves, would of course be picked up. The danger is if something centred elsewhere happens to extend very close to but not actually over your start or finish points, and lies outside the rectangle you are defining with a narrow route.

The only way with a narrow route to ensure you cover that part of the circuit outside the direct line is to use start and finish points outside those aerodromes.

[rustle]

So in theory if you do a circuit that includes the other side, you are into unknown territory. Ditto at the start airfield.Hmmm.. If your circuits extend outside the atz maybe you need some circuit practice ;)
NB Does not apply to Elstree where all circuits are outside the atz

[chrisN]

Don't forget that not all start and finish aerodromes have ATZ's.

I was flying (my glider) from Aston Down (unlicensed, so no ATZ), recently. Not only were there events at Kemble which one could be very close to, there were several days when South Cerney had a parachute drop zone 5nm radius and 12000 feet high, which overlapped Kemble's ATZ and came close enough to Aston Down's downwind area for gliding there to need to be very careful (not so close as to affect the circuit, but certainly affected local soaring). A narrow route from e.g. a gliding site in North Wales to Aston Down would not have picked up that NOTAM if the system does what it says on the tin.

[Mike Cross]

Each NOTAM is given a radius of influence. For a navaid it would usually be the published range, for an aerodrome it is usually 5 nm and for danger areas and suchlike it will extend beyond the boundaries to provide a buffer.

If the circle described by the ROI cuts your route it will be included in the Narrow Route Briefing. The default for your route is 10nm either side of track.

You will also get NOTAM for your departure arrival and any alternate aerodromes you have specified.

A week ago I was asked by someone why he got BIG in his brief even though it was in the opposite direction to where he was going. The answer is because his departure a/d was within range so he could have wanted to use it as a navaid.

One gotcha worthwhile knowing about. If you cross an FIR but have no waypoints within it, eg. EGTR DCT LAM DCT LYD DCT EBCI you MUST include the crossed FIR in the appropriate box.

This route is Elstree, Lambourn, Lydd, Charleroi and crosses the Paris FIR but has no ICAO indicators within it. Stick LFFF in the additional crossed FIR box to make sure you get the LFFF NOTAM.

Re unlicensed a/d's. Chris is right, Popham for example is EGHP and can be used in a NRB, however it is unlicensed and has no ATZ. You won't therefore get an a/d NOTAM but you would still get normal Class G NOTAM, e.g. a Nav Warning for parachuting.

Mike

[IO540]

Incidentally, is there any information which would not appear in a narrow route briefing but which would appear in other types of briefing?

[18greens]

Would it not be more useful if it was a lozenge?

PPL students are taught to calculate MSAs 5 miles beyond destination just in case they overshoot. Should the NRB not also do the same.

I generally want to know the area between Biggin and Rochester out to 20 miles either side. 20 miles beyond both airfield would reduce the risk of hitting a tra or other restriction if you accidentally go beyond destination. To do this I need to put in heathrow to manston.

I also could not find an explanation of a narrow route briefing in the AIs help text, hence the question.

[Mike Cross]

is there any information which would not appear in a narrow route briefing but which would appear in other types of briefing? Yes, info whose radius of influence does not cut your narrow route (well you asked for it) If you want the whole thing go for a Route Briefing.
20 miles beyond both airfield would reduce the risk of hitting a tra or other restriction if you accidentally go beyond destination. If your nav is that bad you ain't going to be able to avoid the TRA anway!

TRA's generally have a radius of influence sufficient to appear if you are flying near them rather than into them.

Let's see, 20 miles beyond both airfields x 20nm route width, that's another 800 square miles!

[Mike Cross]

I have been corrected by the AIS Quality Manager:uhoh: AIS applies, as a general rule, the OPADD/Eurocontrol default radius of 25nm for En-route navigational aids rather than the DOC. This is why users in East Anglia or South of England no longer receive STN information.
Mike

[18greens]

Mike,

Whats wrong with covering a bit beyond destination. People aren't all crack navigators, some people do get it wrong, even people who get paid for it.

And saying its another 800 sq miles, no problem for me I just don't want to read Liverpools Notams when I am flying mainly in Kent.

Perhaps this problem can be solved by printing them in Latitude sequence like they used to be. I've never worked out what sequence they print in. In the old days when they printed in latitude sequence it didn't matter if you got all of them because you started 0.5 degrees below your most southerly lat then up to 0.5 degrees beyond most notherly. Usually a concise list and OK it included some which were way out west but at least you aren't picking through north notams to find southern ones.

In brief a narrow route briefing isn't wide enough and an area briefing is too wide. We need something in the middle

How do we talk direectly to AIS to get their view on it.

[DFC]

From practical experience, I can confim that the shape of the area in the narrow route brief is actually a "lozenge". That is why when I fly say from Oxford to Southampton, I get notam warnings for things on the isle of wight (Kite Flying) which is beyond my destination.

With regard to knowing what is happening 10nm beyond the destination there is a total difference between this and the calculation of safe hight to fly.

We calculate a safe flight to fly at (VFR) or minimum safe altitude (IFR) which includes a distance beyond our destination or turn point so that if we unknowingly fly beyond out destination we will be safe.

However, even if we know that there is a TRA 10nm beyond our destination, if we don't know that we have passed the destination in error, we don't know that we are about to enter the TRA and thus the knowledge at that point is wasted.

Knowledge is only useful when it can be put to good use!

Regards,

DFC

[IO540]

Mike - I take it you are taking the mickie :O So it appears that if one is looking for info which might affect the actual flight (and what on earth is the point is getting Notams for other places????) the Narrow Route Briefing is 100% sufficient in all case.

As to the original question, the effective shape of the area reported must be a "lozenge" because each object described in the Notam is defined by a circle whose radius is chosen to be slightly larger than the geographical area being covered. In many cases, ludicrously larger but that's another subject...

[bookworm]

FWIW, the Avbrief (www.avbrief.com) implementation of NRB uses a lozenge (I call it a "racetrack") shape. It will include items with small radii up to the briefing width beyond the destination.

[18greens]

DFC,

Thanks for confirming its a lozenge, although confirmation from AIS would be comforting.

As to the point about TRA beyond destination. (I can't do quotes). If you fly in straight lines, great. Many pilots do not fly so clinically, aviation is an adventure, hopping from place to place knowing your location, sometimes inverted. What if you want to visit the Cerne Abbas giant beyond Comption Abbas or Leeds Castle beyond Rochester. Or you are general maneouvering around your local airfield or teaching someone lessons 7,8 and 9. Not really going anywhere just a bit of aeros and all you really want to know is are there any big things we all should avoid in the local area. How do we get a NOTAM brief that does that without reading all NOTAMS.

Surely a here to there plus or minus 20 miles or a my airfield radius 30 miles NOTAM brief would suit the majority of pilots.

Regards 18

[Mike Cross]

18GreensIn brief a narrow route briefing isn't wide enough and an area briefing is too wide. You can set the width yourself, 10 nm either side of track is the default, make it 99nm either side if you want.

If you want a briefing for a geographic area within which you intend to bimble the way to do it is to choose two aerodromes which straddle your intended area of operations and use these as your departure and arrival aerodromes. Put your actual departure and arrival aerodromes plus any others you might visit in as alternates.

Now set the narrow route width to whatever is necessary to decribe a rectangular box covering the area you want. You will get all NOTAM affecting the area plus aerodrome NOTAM for all of the aerodromes you entered on the screen.

Talk of the "shape" of the brief is somewhat nonsensical.

A to B, default width gives you a rectangle 20 nm wide with the ends centred on A & B. This is NOT the area within which you will get NOTAM.

If say there is a NOTAM with a radius of influence of 25 nm centred 20 nm beyond your destination it will appear in your brief because its RoI cuts your route. It appears not because the shape is a lozenge, it is there because its influence extends into your intended route.How do we talk direectly to AIS to get their view on it. I know this is a radical suggestion, and some might think it a bit risky, but you could try writing to them either by letter or email or even telephoning them. The postal and email addresses and the telephone numbers are after all on the website:ugh: