Definition
A charted altitude that provides obstacle clearance during a turn at certain fixes or NAVAIDs along an airway or route. It is higher than the surrounding Minimum En Route Altitude (MEA) or Minimum Obstruction Clearance Altitude (MOCA) and applies only when turning at the specified fix, because the turn carries the aircraft into airspace where terrain or obstacles require additional vertical clearance.
Plain English
When you turn at certain points along a route, the ground or obstacles off to the side of the airway can be higher than what you've been flying over. The MTA is the altitude you need to be at to safely make that turn without getting too close to anything below.
Context Anchor
Seen on IFR en route charts and in handbook discussions of en route altitudes, especially where an airway or route changes direction at a specific point.
Why Pilots Care
Ensures terrain and obstacle clearance is maintained when a turn is required under instrument conditions.
Grounding Statement
Picture reaching a route point in cloud and needing to turn: the MTA is the altitude floor that keeps that turn protected.
Intuition Check
Do not read MTA as just another general minimum altitude for the whole route. It applies specifically to the turn at that point.
Example Sentence 1
ATC cleared us direct to the next fix, but the chart showed an MTA of 8,500 feet, so we climbed before initiating the turn.
Example Sentence 2
ATC cleared the aircraft direct only after confirming it could reach the MTA for the required heading change.