Definition
A higher-accuracy version of standard DME used as part of the Microwave Landing System (MLS). It measures the slant-range distance between the aircraft and a ground station with much greater precision than conventional DME, particularly at short ranges close to the runway, to support precision approach and landing operations.
Plain English
It is a more accurate type of distance-measuring equipment, designed to give very precise distance readings during a final approach to landing.
Context Anchor
Seen in avionics, approach-system, and navigation-equipment discussions, especially where precision approach capability is being described.
Derivation
The 'P' stands for 'precision,' distinguishing it from standard DME. 'Precision' comes from the Latin 'praecisio,' meaning 'a cutting off' — the idea of cutting away error to leave a tight, exact value. That captures what DME/P does: it tightens the distance reading so it can be trusted close to the runway.
Why Pilots Care
Provides the distance accuracy needed to fly decision altitudes and missed-approach points safely on precision approaches.
Intuition Check
DME/P is not just regular DME with a different label. The “/P” means it is built and approved for more precise distance guidance in specific approach systems.
Example Sentence 1
The MLS installation included a DME/P transponder to provide precise range information during the final approach.
Example Sentence 2
During the Category II approach the crew relied on DME/P to identify the final approach fix.