jrh
Well-Known Member
Here's a deep dive one of my coworkers questioned me on and I'd like to hear how others handle it, particularly under Part 135...
Scenario is an untowered airport that normally has automated weather, but the automated weather is inop. Multiple approaches are published, including ILS, GPS, and VOR. None of the approaches mention anything about an altimeter setting in the notes section except for a single GPS approach that includes a note saying, "When local altimeter not received, use XYZ altimeter setting," referring to a nearby airport.
Does this mean this is the only approach authorized for use in this scenario?
AIM 5-4-5 says, in part, "When the altimeter setting(s) on which the approach is based is not available, the approach is not authorized."
Part 135.225(b)(2), referring to eligible on-demand operations, says an approach may be conducted "...If no local altimeter setting for the destination airport is available, the pilot may use the current altimeter setting provided by the facility designated on the approach chart for the destination airport."
So basically, my questions are:
What determines if an approach gets a note referring to a remote altimeter setting source? I found the exact formulas and standards for a RASS in FAA Order 8260.3F, but no guidance on when exactly a RASS will be developed for an approach.
Is there a difference between Part 91 operations and Part 135 eligible on-demand operations? The AIM seems to indicate this is a black and white no-go issue, but the wording of 135.225 seems to say whatever altimeter setting ATC gives for the area is an acceptable substitute.
How would a note stating "When local altimeter not received, procedure NA," play in to all of this? According to the AIM, that statement is redundant. Or is it there in order to explicitly prohibit eligible on-demand operators from using the approach when no weather is available?
Scenario is an untowered airport that normally has automated weather, but the automated weather is inop. Multiple approaches are published, including ILS, GPS, and VOR. None of the approaches mention anything about an altimeter setting in the notes section except for a single GPS approach that includes a note saying, "When local altimeter not received, use XYZ altimeter setting," referring to a nearby airport.
Does this mean this is the only approach authorized for use in this scenario?
AIM 5-4-5 says, in part, "When the altimeter setting(s) on which the approach is based is not available, the approach is not authorized."
Part 135.225(b)(2), referring to eligible on-demand operations, says an approach may be conducted "...If no local altimeter setting for the destination airport is available, the pilot may use the current altimeter setting provided by the facility designated on the approach chart for the destination airport."
So basically, my questions are:
What determines if an approach gets a note referring to a remote altimeter setting source? I found the exact formulas and standards for a RASS in FAA Order 8260.3F, but no guidance on when exactly a RASS will be developed for an approach.
Is there a difference between Part 91 operations and Part 135 eligible on-demand operations? The AIM seems to indicate this is a black and white no-go issue, but the wording of 135.225 seems to say whatever altimeter setting ATC gives for the area is an acceptable substitute.
How would a note stating "When local altimeter not received, procedure NA," play in to all of this? According to the AIM, that statement is redundant. Or is it there in order to explicitly prohibit eligible on-demand operators from using the approach when no weather is available?