on a star chart what is the COP for and on a IAP chart what are the # in the category A,B,C,D box IE S-ILS 34, 880/24 557 (600-1/2) and what are the categorys I found most of the info on how to read these chart over at Navdata except for what I ask above Thanks

The numbers mean missed approach points. On the chart I have which is DFW ILS 18R, it shows for missed approach points for all aircraft catagories.S-ILS 18R 753/16 150 (RA 147)S-ILS 18R 703/12 100 (RA 99)The airport elevation is 603 feet. The S means strait in approach to ILS 18 Right753/16 is 753 feet above sea level and 1600 feet Runway visual range.150 is 150 feet above ground level. 603 + 150 = 753.RA 147 is Radar altimeter of 147 feet. 147 + 603 = 750. Not sure why there is 3 foot difference. Maybe you are sitting 3 feet someway or 1 foot in the 2nd example.There are two minimums depending on whether the aircraft and aircrew are certified to the lower missed approach point. Why there are differences of 2 or 3 feet doesn't really matter in a jet going 130 knots but it must mean something.Hope this helps. Hope it's correct.JimCYWGCOP: Changeover point: The charted point where a pilot changes from one navigation facility to the next for course guidence. Not sure what it means.CatagoriesApproach catagories are based on 1.3 times the stall speed in landing configuration at max. gross landing weight.A - 0 - 90 knotsB - 91 - 120 knotsC - 121 - 140 knotsD - 141 - 165 knotsE - above 165 knots

Regarding the COP:If there is no COP stated on the chart, the pilot should change from the preceeding VOR (start of leg) to the next VOR (end of leg)at the mid-point of the segment- or if there is a bend in the segment (regardless of whether the bend is at the mid-point or not) then that bend also defines a COP (for obvious reasons).However- on some straight segments, changing over at the mid-point will not work, as there may be terrain issues that affect the reception of the VORs involved- or it could be that one of the VOR's is a lower output power than the other. In this case, a COP will be noted on the straight segment to ensure that adequate signals are received. The FAA flies airways and looks for reliable navigational data from the VOR at either end of an airway segment (assuming a VOR is at the end of a segment).The above does not include procedures necessary to receice off-airway navigational signals (sometimes used to ID an intersection). That is another whole subject and involves what is called the MRA (or Minimum Reception Altitude)that is sometimes associated with a fix.I hope this helps-Bruce.

Which chart are you reading off of? CONVERGING ILS RWY 18, ILS or LOC RWY 18R, ILS RWY 18R (CAT II), or ILS RWY 18R (CAT III). I'm assuming the (CAT III) as that's the only ones I ever see with multiple straight-in minimums. But the CAT III chart I looked at had only RA heihgts and no visibility constraints.>Catagories>>Approach catagories are based on 1.3 times the stall speed in >landing configuration at max. gross landing weight.>>A - 0 - 90 knots>>B - 91 - 120 knots>>C - 121 - 140 knots>>D - 141 - 165 knots>>E - above 165 knotsIt also depends on that speed you choose to approach at. We fly Piper Warrior IIIs at my flight school which are technically in approach Category A, but we choose to fly approach at 100 knots so we have to take Category B minimums.----------------------------------------------------------------John MorganReal World: KGEG, UND Aerospace Spokane Satillite, Private ASEL 141.2 hrs, 314 landings, 46 inst. apprs.Virtual: MSFS 2004"There is a feeling about an airport that no other piece of ground can have. No matter what the name of the country on whose land it lies, an airport is a place you can see and touch that leads to a reality that can only be thought and felt." - The Bridge Across Forever: A Love Story by Richard Bach