AIM ¶ 8-1-8 — Collision Avoidance Judgment
AIM 8-1-8 explains judgment in collision avoidance: relative altitude cues, collision-course targets, high-hazard areas, cockpit management, and lights.
In Plain English
AIM 8-1-8 builds on the scan techniques in 8-1-6 by addressing the judgment side of avoiding mid-air collisions. Key concepts every student pilot should internalize:
- Relative altitude: Use the horizon as a reference. Traffic above the horizon is likely higher; below the horizon, likely lower.
- Collision-course targets: An aircraft with no relative motion that stays in one scan quadrant — or one that grows larger without lateral/vertical movement — is on a collision course. Take evasive action.
- Right-of-way rules: Know them cold so evasive action complies with the FARs.
- High-hazard areas: Airways near VORs and Class B, C, D, and E surface areas are traffic-rich. Most mid-airs happen in good weather, and being in a radar environment doesn't relieve you of see-and-avoid duties.
- Cockpit management: Pre-flight planning, organized charts, and pre-set frequencies maximize scan time.
- Visibility factors: Clean the windshield; haze, smoke, rain, and sun glare degrade detection.
- Blind spots: Move your head and maneuver the aircraft (e.g., lift a wing) to clear behind structures.
- Lights on day and night for conspicuity; use ATC traffic advisories when available.
This is FAA recommended practice, not a regulation — but it's exactly the airmanship a DPE expects on a checkride.
AIM Source Text
FAA AIM ¶ 8-1-88-1-8. 8-1-8. Judgment Aspects of Collision Avoidance
Introduction. The most important aspects of vision and the techniques to scan for other aircraft are described in paragraph 8-1-6 , Vision in Flight. Pilots should also be familiar with the following information to reduce the possibility of mid‐air collisions. Determining Relative Altitude. Use the horizon as a reference point. If the other aircraft is above the horizon, it is probably on a higher flight path. If the aircraft appears to be below the horizon, it is probably flying at a lower altitude. Taking Appropriate Action. Pilots should be familiar with rules on right‐of‐way, so if an aircraft is on an obvious collision course, one can take immediate evasive action, preferably in compliance with applicable Federal Aviation Regulations. Consider Multiple Threats. The decision to climb, descend, or turn is a matter of personal judgment, but one should anticipate that the other pilot may also be making a quick maneuver. Watch the other aircraft during the maneuver and begin your scanning again immediately since there may be other aircraft in the area. Collision Course Targets. Any aircraft that appears to have no relative motion and stays in one scan quadrant is likely to be on a collision course. Also, if a target shows no lateral or vertical motion, but increases in size, take evasive action. Recognize High Hazard Areas. Airways, especially near VORs, and Class B, Class C, Class D, and Class E surface areas are places where aircraft tend to cluster. Remember, most collisions occur during days when the weather is good. Being in a “radar environment” still requires vigilance to avoid collisions. Cockpit Management. Studying maps, checklists, and manuals before flight, with other proper preflight planning; e.g., noting necessary radio frequencies and organizing cockpit materials, can reduce the amount of time required to look at these items during flight, permitting more scan time. Windshield Conditions. Dirty or bug‐smeared windshields can greatly reduce the ability of pilots to see other aircraft. Keep a clean windshield. Visibility Conditions. Smoke, haze, dust, rain, and flying towards the sun can also greatly reduce the ability to detect targets. Visual Obstructions in the Cockpit. Pilots need to move their heads to see around blind spots caused by fixed aircraft structures, such as door posts, wings, etc. It will be necessary at times to maneuver the aircraft; e.g., lift a wing, to facilitate seeing. Pilots must ensure curtains and other cockpit objects; e.g., maps on glare shield, are removed and stowed during flight. Lights On. Day or night, use of exterior lights can greatly increase the conspicuity of any aircraft. Keep interior lights low at night. ATC Support. ATC facilities often provide radar traffic advisories on a workload‐permitting basis. Flight through Class C and Class D airspace requires communication with ATC. Use this support whenever possible or when required. Previous | Top | Next AIM | ATPUBS | FAA | Send your comments regarding this website.
Oral Exam Questions a DPE Might Ask
Q1How can you tell if traffic you've spotted is above or below your altitude?
Per AIM 8-1-8, use the horizon as a reference point. If the other aircraft appears above the horizon, it's probably on a higher flight path; if below the horizon, it's probably at a lower altitude.
Q2What visual cues indicate that another aircraft is on a collision course with you?
Per AIM 8-1-8, any aircraft that shows no relative motion and remains in one scan quadrant is likely on a collision course. Likewise, a target with no lateral or vertical movement that increases in size requires immediate evasive action.
Q3Where are the high-hazard areas for mid-air collisions, and does flying in radar contact eliminate the risk?
Per AIM 8-1-8, aircraft tend to cluster on airways — especially near VORs — and in Class B, C, D, and E surface areas. Most collisions occur in good weather, and being in a radar environment still requires vigilance; ATC advisories are workload-permitting.
Related Paragraphs in AIM Chapter 8