Definition
TERPs is the FAA standard that governs how all instrument approach, departure, and arrival procedures in the United States are designed. It specifies the obstacle clearance requirements, descent gradients, course widths, and protected airspace dimensions used when building any published instrument procedure. Every instrument approach chart a pilot flies — ILS, RNAV, VOR, LOC, etc. — has been constructed in accordance with TERPs criteria.
Plain English
TERPs is the rulebook used to design instrument approaches. It tells the procedure designer how much room must be kept clear of terrain and obstacles, how steep a descent can be, and how wide the protected airspace has to be. Pilots don't apply TERPs directly — they fly the published procedure that was built using it.
Context Anchor
You encounter TERPs when studying instrument approach procedure charts, especially when learning why charted altitudes, courses, distances, and missed approach instructions are built the way they are.
Derivation
Terminal refers to the airspace and procedures around an airport (as opposed to en route). Instrument Procedures means procedures flown by reference to instruments rather than by looking outside. The acronym TERPs is widely used in writing and conversation as the shorthand name for FAA Order 8260.3, the document that contains these criteria.
Why Pilots Care
TERPs define the protected airspace and minimum altitudes that keep an aircraft clear of obstacles during an instrument approach, directly affecting safety and legality of the procedure.
Intuition Check
Do not read TERPs as just another name for the approach chart. TERPs are the design standards behind the chart; the chart is what the pilot actually flies.
Example Sentence 1
Every approach in the chart book was designed to TERPs criteria, which is why the minimums and descent gradients are standardized.
Example Sentence 2
Changes to TERPs can raise decision altitudes or add step-down fixes to maintain obstacle clearance.