Definition
An FAA directive (United States Standard for Terminal Instrument Procedures, also called TERPS) that establishes the criteria for designing instrument approach, departure, and en route procedures. Change 21 is a specific revision to that order, which redefined how aircraft approach categories are determined — most notably allowing approach category to be based on the actual approach speed flown rather than only on 1.3 times the stall speed at maximum landing weight (VREF or 1.3 VS0).
Plain English
This is the official FAA rulebook for designing instrument approach procedures. The 'Change 21' part is one specific update to that rulebook that adjusted how a pilot picks the right approach category for the speed they're actually flying.
Context Anchor
Seen when the Instrument Procedures Handbook explains aircraft approach categories and the standards behind instrument approach minimums.
Derivation
TERPS orders are numbered FAA documents; '8260.3' is the document number and 'Change 21' simply means the 21st revision. Knowing this helps pilots recognise that newer 'Changes' supersede older guidance on the same topic.
Why Pilots Care
The revision can change minimums, protected airspace, and which approach category applies to a given aircraft, directly affecting what procedures a pilot may fly.
Analogy
It is like citing a specific edition and update of a building code. The handbook is not inventing the rule; it is pointing to the official standard behind it.
Intuition Check
“Order” here does not mean an air traffic control instruction to a pilot. “Change” here does not mean something the pilot changes in flight; it means an official revision to an FAA standards document.
Example Sentence 1
Because Change 21 to FAA Order 8260.3 lets approach category be based on actual approach speed, the crew used Category C minimums when their landing speed exceeded the Category B threshold.
Example Sentence 2
Before filing an approach, the pilot confirmed the aircraft still met the speed limits listed in FAA Order 8260.3 Change 21.