Definition
A published, FAA-approved series of predetermined maneuvers that allows a pilot to descend by reference to instruments alone from en route altitude to a point near a runway from which a landing can be made visually, or from which a missed approach is executed if the runway environment is not in sight. Each SIAP specifies the navigation aids used, courses to fly, altitudes to maintain at each segment, required obstacle clearance, minimum descent altitudes or decision altitudes, and missed approach instructions. SIAPs are depicted on instrument approach procedure charts and are governed by Title 14 CFR Part 97.
Plain English
An official, step-by-step set of instructions a pilot follows on instruments to safely line up with a runway and come down through clouds or low visibility until they can either see the runway and land, or give up the approach and climb away.
Context Anchor
Seen on instrument approach charts, in instrument flight planning, and in FAA discussions of how pilots approach an airport in low visibility or cloud.
Derivation
"Standard" because the procedure is published and uniform — every pilot flying it follows the same path, altitudes, and minimums. "Instrument approach procedure" because the pilot navigates and descends by reference to cockpit instruments rather than looking outside. The word "standard" is what makes a SIAP different from a special or tailored approach designed for a single operator.
Why Pilots Care
They allow consistent, safe descents and landings when visibility is low or the airport is obscured by weather.
Intuition Check
“Standard” does not mean merely common or suggested here; it means officially published and approved. “Instrument” does not just mean the airplane has instruments; it means the procedure is designed to be flown by reference to instruments when visual cues may be limited.
Example Sentence 1
ATC cleared the pilot for the SIAP into Runway 27, and she briefed the chart before beginning the descent.
Example Sentence 2
SIAPs list the minimum altitude allowed at each step of the approach.