JEPP Chart MSA

[Bil Derberg]

I was wondering if the MSA on the JEPP chart 25NM, or 100NM?

Thanks.

[ahramin]

25.

[Pratt X 3]

The 100 mile safe altitude is pretty much a Canadian thing. If you have a look at a Canadian Jepp chart, it will be listed in the notes section with the altimeter setting, transition level and altitude.

[Cessna 180]

25 nm. The 100nm safe alt is a Canadian thing as another poster mentioned. If there is a 100nm safe alt (or some other alt), it will be annotated in the notes.

As you can see in the lower left of the chart, this procedure was created under the FAA TERPS Order. If you really want to dig into what the procedure needs to provide at a minimum and how these numbers are generated, you can see them here https://www.faa.gov/documentLibrary/med ... 3D_vs3.pdf.

Here's an example where a chart uses a different altitude for an MSA based on different fixes. Mich like the Canadian 100nm safe alt, this allows decent from the en route environment to approach.

01216R5.png (88.33 KiB) Viewed 1186 times

Notice that SIVAE has a safe alt of 10800 between 321 degrees and 231 degrees from 30nm out, and 8300 from 11nm out. HUMEB has a similar transition.

01216R23.png (73.76 KiB) Viewed 1186 times

On this approach there is a standard 25nm safe alt of 7600 (based on RW23), but there are lower transitions to the IAF from YEDNU and CIMGO, which are intersections on an airway near this airport.

CYZY_RNAV_GNSS_RWY_35.png (59.62 KiB) Viewed 1186 times

This is similar to the RNAV 35 in Mackenzie, BC where I would be limited to 10,800 100nm from the airport, unless I transition on from V306 from DAVII or FREND where I can decent to a much lower altitude (even lower than the 25nm safe) if I fly the published transition.


These will all be displayed similarly on a Jepp chart (sorry I don't have a subscription for these airports), you'll find they are displayed similarly.

[Cessna 180]

To add a little more, you'll occasionally see 100nm safe altitudes in the US, generally referred to as the "Emergency Safe Altitude." These are found primarily on military charts. (I've highlighted the EMERG SAFE ALT).

00227HILZ21L.png (103.77 KiB) Viewed 1154 times

[ReserveTank]

MSA=Minimum Sector Altitude, which is 25NM around the indicated navaid. It provides at least 1000' clearance above anything in that circle.
The FAA equivalent of the TC 100NM Safe Altitude was indicated on the previous poster's Nellis plate.

There are also TAA altitudes, which are altitudes for transitioning down to the approach.
For example, on the ICT RNAV 14, You are arriving from the SW at, say, 10000'. You are cleared for the approach, fly direct FEBIT, cross FEBIT at or above 3600'. As long as you are within 30NM from FEBIT you can fly at 3600'. Realistically, you'll likely plan for your VNAV to cross FEBIT at 3600' so you don't waste fuel.

[telex]

MINIMUM SECTOR ALTITUDE (MSA) (ICAO) —
The lowest altitude which may be used which will provide a minimum clearance of 300m (1000ft) above all
objects located in an area contained within a sector
of a circle of 46km (25NM) radius centered on a radio
aid to navigation.

Go here for the chart decode.

https://ww2.jeppesen.com/wp-content/upl ... Charts.pdf