AIM 

9/5/24 

(a) 

Precision Approach (PA). An instrument approach based on a navigation system that provides course 

and glidepath deviation information meeting the precision standards of ICAO Annex 10. For example, PAR, ILS, 

and GLS are precision approaches. 

(b) 

Approach with Vertical Guidance (APV). An instrument approach based on a navigation system that 

is not required to meet the precision approach standards of ICAO Annex 10 but provides course and glidepath 

deviation information. For example, Baro

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VNAV, LDA with glidepath, LNAV/VNAV and LPV are APV 

approaches. 

(c) 

Nonprecision Approach (NPA). An instrument approach based on a navigation system which 

provides course deviation information, but no glidepath deviation information. For example, VOR, NDB and 

LNAV. As noted in subparagraph k, Vertical Descent Angle (VDA) on Nonprecision Approaches, some approach 

procedures may provide a Vertical Descent Angle as an aid in flying a stabilized approach, without requiring its 

use in order to fly the procedure. This does not make the approach an APV procedure, since it must still be flown 

to an MDA and has not been evaluated with a glidepath. 

b. 

The method used to depict prescribed altitudes on instrument approach charts differs according to 

techniques employed by different chart publishers. Prescribed altitudes may be depicted in four different 

configurations: minimum, maximum, mandatory, and recommended. The U.S. Government distributes charts 

produced by National Geospatial

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Intelligence Agency (NGA) and FAA. Altitudes are depicted on these charts 

in the profile view with underscore, overscore, both or none to identify them as minimum, maximum, mandatory 

or recommended. 

1. 

Minimum altitude will be depicted with the altitude value underscored. Aircraft are required to maintain 

altitude at or above the depicted value, e.g., 3000. 

2. 

Maximum altitude will be depicted with the altitude value overscored. Aircraft are required to maintain 

altitude at or below the depicted value, e.g., 4000. 

3. 

Mandatory altitude will be depicted with the altitude value both underscored and overscored. Aircraft 

are required to maintain altitude at the depicted value, e.g., 5000. 

4. 

Recommended altitude will be depicted with no overscore or underscore. These altitudes are depicted 

for descent planning, e.g., 6000. 

NOTE

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1. 

Pilots are cautioned to adhere to altitudes as prescribed because, in certain instances, they may be used as the basis for 

vertical separation of aircraft by ATC. When a depicted altitude is specified in the ATC clearance, that altitude becomes 

mandatory as defined above. 

2. 

The ILS glide slope is intended to be intercepted at the published glide slope intercept altitude. This point marks the PFAF 

and is depicted by the ”lightning bolt” symbol on U.S. Government charts. Intercepting the glide slope at this altitude marks 
the beginning of the final approach segment and ensures required obstacle clearance during descent from the glide slope 
intercept altitude to the lowest published decision altitude for the approach.  Interception and tracking of the glide slope 
prior to the published glide slope interception altitude does not necessarily ensure that minimum, maximum, and/or 
mandatory altitudes published for any preceding fixes will be complied with during the descent. If the pilot chooses to track 
the glide slope prior to the glide slope interception altitude, they remain responsible for complying with published altitudes 
for any preceding stepdown fixes encountered during the subsequent  descent. 

3. 

Approaches used for simultaneous (parallel) independent and simultaneous close parallel operations procedurally 

require descending on the glideslope from the altitude at which the approach clearance is issued (refer to 5

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4

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15 and 

5

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4

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16). For simultaneous close parallel (PRM) approaches, the Attention All Users Page (AAUP) may publish a note 

which indicates that descending on the glideslope/glidepath meets all crossing restrictions. However, if no such note is 
published, and for simultaneous independent approaches (4300 and greater runway separation) where an AAUP is not 
published, pilots are cautioned to monitor their descent on the glideslope/path outside of the PFAF to ensure compliance 
with published crossing restrictions during simultaneous operations. 

4. 

When parallel approach courses are less than 2500 feet apart and reduced in-trail spacing is authorized for simultaneous 

dependent operations, a chart note will indicate that simultaneous operations require use of vertical guidance and that the 

Arrival Procedures

5

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4

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