Definition
A correction added to a planned descent distance to account for the slowing effect of a headwind on groundspeed during descent. Because a headwind reduces the distance covered per minute, the descent must be started earlier (farther from the destination or fix) than the still-air calculation would suggest.
Plain English
Extra miles added to where you start your descent because a headwind is slowing you down. The stronger the headwind, the sooner you have to begin coming down to reach your target altitude on time.
Context Anchor
Seen when planning the top of descent or checking whether a high-performance aircraft can meet an altitude restriction during descent.
Derivation
“Headwind” means wind coming from ahead of the aircraft, against its path of travel. “Adjustment” means a correction or change. Together, the term points to correcting the descent plan for the effect of wind from ahead.
Why Pilots Care
Ensures the aircraft reaches the target altitude at the correct horizontal point rather than arriving too high or too low.
Grounding Statement
With a headwind, the aircraft is still flying through the air, but it covers fewer miles over the ground in the same amount of time.
Intuition Check
Do not assume a headwind only affects arrival time. In descent planning, it also affects how far across the ground the aircraft travels while losing altitude.
Example Sentence 1
With a 40-knot headwind reported at cruise altitude, the captain added a headwind adjustment of several miles to the planned top-of-descent point.
Example Sentence 2
A 25-knot headwind required a headwind adjustment that lengthened the total descent distance from 12 to 15 nautical miles.