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A320 OPS & LVP THEORY

A320 LVP Theory

TECHNICAL REFERENCE
01 Differences Between CAT III A, B & C

All CAT III General Standard: Decision Height < 100ft or No DH | Autoland Required

Category Decision Height (DH) Runway Visual Range (RVR) Notes & Visual Requirements
CAT 3A DH < 100ft / NONE RVR > 200m Autoland required. Required visuals: ≥ 3 consecutive lights.
CAT 3B DH < 50ft / NONE RVR 200m - 75m Autoland required. Required visuals: ≥ 3 consecutive lights (FP) or Centerline light attained & maintained (FO).
CAT 3C NO DH NO RVR LIMIT No VISUAL ref. required! Note: It's very rare and basically doesn't exist. Even if landing is possible, how are pilots gonna taxi? Like, it's impossible zero vis.
02 Approach Ban Concept

This is the regulation stating that you must not continue an instrument approach below a certain altitude if the RVR / ceiling is below the required minimum.

You're allowed to start an approach no matter the weather, BUT you must not continue that approach past a certain point: "the approach ban point" if the required vis. / RVR is lower than required.

Approach Ban Height
1000 FT AAL
  • Insufficient RVR / wx at 1000ft (AAL): Go-around required.
  • Insufficient RVR / wx < 1000ft (AAL): Continuation allowed if weather was sufficient prior to passing 1000ft (AAL).
03 Differences Between CAT 1, 2 & 3

Primary Categorization Factors:

  • 1) Minima & RVR
  • 2) ACFT capabilities: RA, dual AP, etc...
  • 3) Ground equipment: ILS signal integrity, runway lighting, etc...
  • 4) Crew qualifications

Aircraft Equipment:

  • CAT 1: Min. 1 ILS receiver & AP/FD function, baro altimeter
  • CAT 2: 2 ILS receivers, RA, coupled AP, ACFT & operator approved
  • CAT 3: Autoland function, dual AP, RA, fail-passive / fail-operational
04 Fail-Passive vs. Fail-Operational
  • FP = CAT 2/3 "SINGLE": 1 AP & if a failure occurs < AH, nothing dangerous/drastic will happen but pilot intervention is required.
  • Logic: If it breaks, it doesn't screw things up for you, it just stops helping.
  • FO = CAT 2/3 "DUAL": 2 AP & if a failure occurs < AH, the remaining automation can continue safely.
  • Logic: If a part breaks, it doesn't screw things up AND it can continue safely on the healthy parts.
Summary: Fail-passive = CAT 3 "SINGLE" (1 AP) | Fail-operational = CAT 3 "DUAL" (2 AP)
05 Difference Between VV & Ceiling

Ceiling: Clear sky / visibility < ceiling. It's classified as the first layer of either BKN or OVC cloud.

VV (Vertical Visibility): This is used when there's actually no ceiling because at ground level you're already inside the phenomenon (fog, mist, cloud, etc.).

  • So instead, when this is the case, the literal "vertical" visibility is measured, essentially acting as a ceiling from the pilot's POV.
  • If VV002 = essentially ceiling 200ft.
  • EXCEPT: < 200ft, RVR will obviously be reduced!
06 Required Visuals at Minima
  • CAT 1: ALS, runway edge lights, thresh. lights, TDZ lights, PAPI, etc... Anything that's related with the runway environment.
  • CAT 2: 1) ≥ 3 consecutive lights (ALS, TDZ lights, ctd lights). 2) 1 lateral element (crossbar threshold lights).
  • CAT 3A & CAT 3B (FP): ≥ 3 consecutive lights.
  • CAT 3B (FO): Centerline light (runway / ALS) attained & maintained.
  • CAT 3B / 3C (autoland): No VISUAL ref. required!
07 RVR & Low-Vis Takeoff (LVTO)

A320 ops - LVP: RVR < 550m or ceiling < 200ft

RVR (Runway Visual Range) is usually calculated in 3 different areas along the runway: TDZ, MID, END.

LVTO Limits:

  • RVR > 550m: Normal takeoff
  • RVR < 550m: LVTO takeoff
  • RVR < 400m: Additional special approval is required.
08 Alert Height (AH) & MUH

Alert Height (AH): AH is only relevant on CAT 3 approaches. The AH varies from ACFT model, for the A320, it's 100ft AGL.

  • > AH: If a system fails / autoland button flashes, you go-around.
  • < AH: If a system fails, you continue, this is because you're so close to the ground that it's more dangerous to go-around.

Minimum Use Heights (MUH):

  • CAT 1 ILS: 160ft AGL
  • CAT 2/3 ILS: 0ft AGL (if you plan a manual landing, CAT 2 = 80ft AGL)
  • NPA: 200ft AGL
  • Circling approach: 500ft AGL
  • Autothrottle: Disconnect by 1000ft (AAL) minimum.
09 Good Airmanship / Safety

If Go-Around is wx related: Max 2 approaches.

ONLY try a 3rd approach if wx has improved 2x what it was (ex: RVR = 200m → 2 failed approaches. RVR = 400m from 200 → Allowed 3rd approach).

Logic Breakdown:

  • 1st failed app.: Acceptable
  • 2nd failed app.: Only try a 2nd approach if there's a reasonable chance of success.
  • 3rd approach: Only try if wx has 2x improved.

Why ever fly CAT 2 when you have CAT 3?

The general rule is that you must match the CAT of approach with the wx conditions. It's a ladder you climb down as needed. See app & dep. vids for more!

10 Lights SOP & Wind Limits

Lights SOP in LVP:

  • Landing lights: Always off
  • Nosewheel lights: NEVER on T/O position
  • Runway turnoff lights: As normal

Wind Limitations (Autoland CAT 2/3):

  • Headwind: 30kt
  • Crosswind: 20kt ⇒ 15kt if auto-rollout
  • Tailwind: 10kt
11 Quick Cockpit Checklist Notes
  • Use wing lights
  • Tune ILS frequency for T/O
  • Approach ban?