Gary Drescher wrote:

wrote in message ...


"Steven P. McNicoll" wrote:

wrote in message
...

You are correct. There is no end to what some flight instructors will
dream
up or invent. Everything the FAA does in the world of charting is
predicated
on IAS.

Not quite everything. The approach timing table uses ground speed.

More correctly, the Jeppesen timing table states ground speed. NACO does
not.

Whether they state it or not, there's nothing but ground speed that they
*could* be using to calculate the time to traverse the stated distance.

--Gary

For the best accuracy, it obviously has to be ground speed. But, there is no
requirement to make the necessary calculations to arrive at ground speed. A
lot of folks over many years have simply treated the timing table values as
indicated airspace, on the premise there are a lot more important things to do
in the final approach segment than attempt to make conversions.

In recent years, RNAV has all-but-eliminated any need to use the timing table
in any case.