AIM Text
A clearance for a specific type of approach (ILS, RNAV, GLS, ADF, VOR or Visual Approach) to an aircraft operating on an IFR flight plan does not mean that landing priority will be given over other traffic. ATCTs handle all aircraft, regardless of the type of flight plan, on a “first-come, first-served” basis. Therefore, because of local traffic or runway in use, it may be necessary for the controller in the interest of safety, to provide a different landing sequence. In any case, a landing sequence will be issued to each aircraft as soon as possible to enable the pilot to properly adjust the aircraft's flight path.
Source: FAA Aeronautical Information Manual · current edition · paragraph 5-4-26.
Research Notes
AIM 5-4-26 covers Approach and Landing Minimums — the regulatory minimums for instrument approaches.
Standard alternate minimums:
- Precision approach (ILS/PAR): 600' ceiling, 2 SM visibility
- Non-precision approach (VOR, LOC, RNAV LNAV): 800' ceiling, 2 SM visibility
- No instrument approach: VFR conditions from the MEA
Standard takeoff minimums:
- 1- or 2-engine aircraft: 1 SM visibility
- 3- or 4-engine aircraft: ½ SM visibility
- Helicopters: ½ SM visibility
The 1-2-3 alternate rule (per § 91.169): No alternate required if forecast at destination from 1 hour before to 1 hour after ETA is at least 2,000 ceiling AND 3 SM visibility.
Non-standard alternate minimums: Some approaches have "NA" (not authorized) or non-standard minimums published. Always check the alternate planning notes on the approach chart.
Reference: § 91.169; AIM 5-4-26; FAA-H-8083-16 Chapter 5.