Definition
A position along an aircraft's flight path that lies directly to the side (90 degrees off the wingtip) of a named navigation fix. The aircraft is considered abeam the fix when the fix is perpendicular to the aircraft's track, neither ahead nor behind.
Plain English
The point on your route where a named landmark or navigation point is directly off to your side, level with your wingtip rather than in front of or behind you.
Context Anchor
Seen in navigation, approach, and position-report instructions when a pilot needs to identify the point where the aircraft is alongside a runway, airport, or other reference point.
Derivation
Abeam' comes from old nautical use: 'a-' meaning 'on' and 'beam' meaning the widest side of a ship. A point abeam a ship is straight off its side. Aviation borrowed the term unchanged—abeam in an aircraft means 90 degrees off the wing.
Why Pilots Care
Abeam positions are commonly used as turning points and reporting points. Misjudging when you are abeam a fix can mean turning early or late on an approach or in a holding pattern, which affects spacing, separation, and approach geometry.
Analogy
It is like driving past a landmark on a road and saying, “The gas station is directly beside me now.” You are not at the gas station, but you are lined up with it from the side.
Intuition Check
Abeam does not mean ahead of you or behind you. It means off to your left or right side, roughly at a right angle to your path.
Example Sentence 1
The controller instructed the pilot to begin the descent when abeam the fix.
Example Sentence 2
Passing the abeam fix in the hold, the crew turned to the inbound course.