AIM ¶ 1-1-20 — Special Precision Approach Procedures

AIM 1-1-20 covers precision approach systems other than ILS and GLS. Because these systems aren't part of the standard public approach inventory, their use requires the FAA to issue special instrument approach procedures (SIAPs).

Key points to remember:

• A special IAP is issued when an operator's pilot training, aircraft equipment, or aircraft performance differs from what's required for published procedures.
• Special procedures are not distributed for public use — you won't find them in the standard chart subscription. They're issued only to the specific operator who meets the approval criteria.
• General aviation operators seeking approval contact their local Flight Standards District Office (FSDO) to obtain a letter of authorization (LOA).
• Air carrier operators work through their Certificate Holding District Office (CHDO) to get approval added to their Operations Specifications (OpSpecs).

Operationally, this matters because it lets operators with advanced or non-standard equipment (or specialized training) safely use approaches that aren't available to the general flying public, while ensuring proper FAA oversight. AIM guidance is informational — the actual authorization comes through your LOA or OpSpecs.