Minimum Safe Altitude (MSA) Standards

Andrew Sarangan wrote:

I realize that that is what the AIM says, but why are they to be used
for emergencies only? I always interpreted the MSA as the minimum
altitude to use when flying off-feeder routes (direct to the IAF),
sort of like the OROCA when flying off-airways.


In many countries MSAs are operational altitudes. They are not in the United States. And, in a
designated mountainous area you are required by 91.177 to have 2,000 feet vertically or 4 miles
laterally when off a published route or segment. MSAs are not IFR altitudes, routes, or segments.

wrote in message ...
Andrew Sarangan wrote:

I realize that that is what the AIM says, but why are they to be used
for emergencies only? I always interpreted the MSA as the minimum
altitude to use when flying off-feeder routes (direct to the IAF),
sort of like the OROCA when flying off-airways.


In many countries MSAs are operational altitudes. They are not in the United States. And, in a
designated mountainous area you are required by 91.177 to have 2,000 feet vertically or 4 miles
laterally when off a published route or segment. MSAs are not IFR altitudes, routes, or segments.

I agree that MSA does not satisfy the altitudes in mountainous areas.
But in nonmountainous areas MSA does satisfy the altitude
requirements. What am I missing here?

Andrew Sarangan wrote:



I agree that MSA does not satisfy the altitudes in mountainous areas.
But in nonmountainous areas MSA does satisfy the altitude
requirements. What am I missing here?

That they are not published as IFR altitudes under either of the pertinent IFR alitude regulations, Part
95 or Part 97.

MSA's do not ensure NAVAID or radio reception, and may even contain
sectors that are known areas of no signal coverage. They just ensure 951
feet of obstacle clearance within the specified distance from the NAVAID.

JPH

Andrew Sarangan wrote:
wrote in message ...

Andrew Sarangan wrote:


I realize that that is what the AIM says, but why are they to be used
for emergencies only? I always interpreted the MSA as the minimum
altitude to use when flying off-feeder routes (direct to the IAF),
sort of like the OROCA when flying off-airways.


In many countries MSAs are operational altitudes. They are not in the United States. And, in a
designated mountainous area you are required by 91.177 to have 2,000 feet vertically or 4 miles
laterally when off a published route or segment. MSAs are not IFR altitudes, routes, or segments.


I agree that MSA does not satisfy the altitudes in mountainous areas.
But in nonmountainous areas MSA does satisfy the altitude
requirements. What am I missing here?

I defer to sammy, who says what I would have said.

Bob

"Andrew Sarangan" wrote in message
om...
I realize that that is what the AIM says, but why are they to be used
for emergencies only? I always interpreted the MSA as the minimum
altitude to use when flying off-feeder routes (direct to the IAF),
sort of like the OROCA when flying off-airways.





"Bob Gardner" wrote in message
news:EJJ2c.135940$4o.172500@attbi_s52...
The context of minimum sector altitudes is important...they are to be
used
only in emergencies. I see many postings in which a pilot is trying to
fit
an MSA into an approach procedure.

Bob Gardner