AIM 

3/21/24 

and low

−

visibility approach and landing operations. Systems of concern include Terrain Awareness Warning 

Systems (TAWS), Enhanced Ground Proximity Warning Systems (EGPWS), and Traffic Collision Avoidance 

Systems (TCAS), to name a few. Pilots of radio altimeter equipped aircraft should become familiar with the radio 

altimeter’s interdependence with the other aircraft systems and expected failure modes and indications that may 

be associated with harmful interference. 

b. 

Actions. Recognizing interference/anomalies in the radio altimeter can be difficult, as it may present as 

inoperative or erroneous data. Pilots need to monitor their automation, as well as their radio altimeters for 

discrepancies, and be prepared to take action. Pilots encountering radio altimeter interference/anomalies should 

transition to procedures that do not require the radio altimeter, and inform Air Traffic Control (ATC). 

c. 

Inflight Reporting. Pilots should report any radio altimeter anomaly to ATC as soon as practical. 

d. 

Post Flight Reporting. 

1. 

Pilots are encouraged to submit detailed reports of radio altimeter interference/anomalies post flight as 

soon as practical, by internet via the Radio Altimeter Anomaly Reporting Form at 

https://www.faa.gov/air_traffic/nas/RADALT_reports/. 

2. 

The post flight pilot reports of radio altimeter anomalies should contain as much of the following 

information as applicable: 

(a) 

Date and time the anomaly was observed; 

(b) 

Location of the aircraft at the time the anomaly started and ended (e.g., latitude, longitude or 

bearing/distance from a reference point or navigational aid); 

(c) 

Magnetic heading; 

(d) 

Altitude (MSL/AGL); 

(e) 

Aircraft Type (make/model); 

(f) 

Flight Number or Aircraft Registration Number; 

(g) 

Meteorological conditions; 

(h) 

Type of radio altimeter in use (e.g., make/model/software series or version), if known; 

(i) 

Event overview; 

(j) 

Consequences/operational impact (e.g., impacted equipment, actions taken to mitigate the disruption 

and/or remedy provided by ATC, required post flight pilot and maintenance actions). 

7

−

6

−

3.  VFR in Congested Areas 

A high percentage of near midair collisions occur below 8,000 feet AGL and within 30 miles of an airport. When 

operating VFR in these highly congested areas, whether you intend to land at an airport within the area or are 

just flying through, it is recommended that extra vigilance be maintained and that you monitor an appropriate 

control frequency. Normally the appropriate frequency is an approach control frequency. By such monitoring 

action you can “get the picture” of the traffic in your area. When the approach controller has radar, radar traffic 

advisories may be given to VFR pilots upon request. 

REFERENCE

−

 

AIM, Para 4

−

1

−

15, Radar Traffic Information Service. 

7

−

6

−

4.  Obstructions To Flight 

a. 

General. Many structures exist that could significantly affect the safety of your flight when operating below 

500 feet above ground level (AGL), and particularly below 200 feet AGL. While 14 CFR Part 91.119 allows 

flight below 500 feet AGL when over sparsely populated areas or open water, such operations involve increased 

7

−

6

−

2 

Potential Flight Hazards