T-6A INSTRUMENT NAVIGATION
INSTRUMENT DEPARTURE PROCEDURE - A preplanned instrument flight rule (IFR)
ATC departure procedure printed for aircrew use in graphic and/or textual form. DPs provide
transition from the terminal to the appropriate enroute structure.
INSTRUMENT METEOROLOGICAL CONDITIONS - Weather conditions (visibility,
ceiling and cloud clearance) below the minimums for flight under visual flight rules (VFR).
INTERMEDIATE APPROACH SEGMENT - The part of an IAP from the first arrival at the
first navigational facility or predetermined fix, to the beginning of the final approach.
INTERSECTION - An intersection is a point defined by a combination of 2 or more radials
from 2 or more NAVAIDs. An intersection may also be defined as a radial and DME.
Intersections may be used to indicate fixed positions along the airways.
JET ROUTES - A high altitude route system extending from 18,000 feet MSL to FL450,
inclusive. The routes are predicated by high altitude NAVAID.
MANDATORY ALTITUDE (INSTRUMENT APPROACH) - The MSL altitude vertical to a
geographic location, which an aircraft must maintain during a portion of an instrument approach.
The requirement for such may be created by airspace separation criteria or airspace separation
criteria in conjunction with obstruction clearance criteria. A mandatory altitude will be depicted
as an underlined number with a line above it.
MANEUVERING AIRSPACE - Airspace used at an IAF to allow an aircraft to maneuver for a
favorable alignment with the initial approach course.
MAXIMUM ALTITUDE (INSTRUMENT APPROACH) - The MSL altitude vertical to a
geographic location above which an aircraft may not be flown during an instrument approach
until after passing the location. The requirement for a maximum altitude may be created by
airspace separation criteria. On the approach plate, a maximum altitude will be depicted as a
number with a line above it.
MINIMUM CROSSING ALTITUDE - The lowest altitudes at certain fixes at which an
aircraft must cross when proceeding in the direction of a higher Minimum Enroute IFR Altitude.
MINIMUM DESCENT ALTITUDE - The lowest altitude, expressed in feet above MSL, to
which descent is authorized on final approach or during circling-to-land maneuvering in
execution of a standard IAP where no electronic glideslope is provided.
MINIMUM ENROUTE ALTITUDE - The altitude established between NAVAIDs or
reporting points on airways, air routes, or advisory routes, which will meet obstruction clearance
requirements, and which will also assure acceptable navigational signal coverage.
MINIMUM FUEL - Indicates an aircraft's fuel supply has reached a state where, upon reaching
the destination, it can accept little or no delay. This is not an emergency situation but merely
indicates an emergency situation is possible should any undue delay occur. The pilot is not to
expect priority handling unless specifically requested or declares "emergency fuel."