Low Visibility Procedures (LVP)[PDF]
- 1 Introduction
- 2 Controller requirements
- 3 Pilot requirements
- 4 Approach Categories
- 5 Hazards
- 6 See also
- 7 Reference
- 8 Author
Low visibility procedures exist to support low visibility operations at aerodromes.
AUTOLAND can be also performed during normal operation.
When meteorological conditions deteriorate to such an extent that the cloud base drops to a certain level, or the horizontal visibility decreases below a certain value, then it might become necessary to establish Low Visibility Procedures at your airfield.
Need to establish Low Visibility Procedures
LVTO Triggering conditions
LVP Triggering conditions
Implications with introducing Low Visibility Procedures
- Increase separation between landing and departing traffic even on aerodromes with different runways for landing and taking-off.
- Conditional clearances can no longer be given.
- Give taxi clearances with precaution and monitor his ground radar because pilots may not be able to see each other until the very last moment.
- CAT II/III holding points shall now be used, instead of the normal holding points. The ILS sensitive area must be protected and extra distance from runway will prevent unwanted runway incursion.
The Runway Visual Range (RVR) is the most important parameter for pilots.
You can instruct the pilot to use CAT II/III holding points to protect the ILS sensitive area. Since the ILS equipment in our flight simulator is not sensitive to aircraft presence inside the protected area, you can use the CAT II/III holding points in order to have more free space in front of the runway to prevent unwanted runway incursion.
- The status of the visual and non-visual facilities is sufficient
- Appropriate LVPs are in force according to information received from air traffic services (ATS)
- Flight crew members are properly qualified (non-applicable in IVAO)
Low visibility operation requirements
These operations shall be only conducted if:
- the aircraft concerned is certified for operations with a decision height (DH) below 200ft, or no DH, and equipped in accordance with the applicable airworthiness requirements;
- a system for recording approach and/or automatic landing success and failure is established (non-applicable in IVAO)
- the DH is determined by means of a radio altimeter;
- the flight crew consists of at least two pilots (non-applicable in IVAO)
- all height call-outs below 200ft above the aerodrome threshold elevation are determined by a radio altimeter
Cloud base, RVR and Visual Reference
The cloud base does not stop the pilots from flying a CAT I approach legally.
Low visibility on ground
When the runway is CAT II/III equipped and has only one holding point mark, this holding point is compliant with the CAT II/III safeguarding.
When the runway is CAT II/III equipped and has more than one holding point, the closest holding point to the runway (marked the same as in the situation with only one holding point) can be only used outside low visibility operation (CAT I). The holding point situated further from the runway has a different marking as shown in the picture. This holding point is situated far enough from the runway in order to protect the ILS sensitive area and will be used during low visibility operation (CAT II/III).
In real airfields, controllers can switch the green taxi lights, and the red stop bars ON/OFF, thus creating taxi routes with clear visual clues to the pilots. (not applicable in IVAO).
In some airfields, during low visibility operation, aircraft can call an external help in order to join the apron if they are not familiar with the airfield. The airfield controller will then send a follow me car, which can guide the aircraft on the ground.
As a controller you are supposed to know what approach category the equipment at your airfield can support. The pilots are responsible to check which category they can fly with their aircraft, and which category they are authorized to fly by the local authorities and their company.
Category and visual reference
|Precision Approach Category||Minimum DH||Minimum RVR required||Visual reference required by the pilot|
|Normal Operations||CAT I||DH ≥ 200ft (60m)||RVR ≥ 550m or VIS ≥ 800m
RVR ≥ 1750ft or VIS ≥ 2400ft
|Approach light system elements. Threshold marking, threshold lights or identification lights. Visual glideslope indications.
Touchdown zone. Runway edge lights.
|Low Visibility Procedures||CAT II||100ft ≤ DH < 200ft||RVR ≥ 350 m||3 consecutive lights found in:
Lateral reference is required
|Low Visibility Procedures||CAT IIIA||No DH or DH < 100 ft||RVR ≥ 200m or
RVR ≥ 700 ft
|3 consecutive lights found in:
Lateral reference is required
|Low Visibility Procedures||CAT IIIB||No DH or DH < 50 ft||50 m ≤ RVR < 200 m
150 ft ≤ RVR < 700 ft
|1 light at decision height if above 0ft |
No visual reference required in case of no DH
|Low Visibility Procedures||CAT IIIC||No DH||No RVR requirements||No visual reference required|
Category I ILS Approach
This usually is the approach that will provide the pilots with the lowest approach minima before low visibility procedures have to be flown.
Category II and Category III ILS Approaches
Runway Visual Range (RVR)
On real airfields, the RVR should be measured by means of instruments placed alongside the runway. RVR measurements are taken in 3 zones:
- Stop end
Example: EGSS 280950Z 00000KT 0300 R22/0550V1000D FG VV001 5/5 Q1014
In this example, the RVR on runway 22 is between 550m and 1000m even if the global visibility is 300m.
The risk of inadvertent runway incursion by taxiing aircraft is greatest at aerodromes with complex layouts and multiple runway access points. This risk can only be managed adequately by the application of procedures that provide the pilot with clear, unambiguous guidance on routing and holding points or ground traffic patterns.
- ICAO Documentation 4444 - Air Traffic Management - 16th Edition 2016 - Chapter 7.12
- VID 150259 - Creation
- VID 150259 - Wiki Integration
DATE OF SUBMISSION
- 01:03, 14 May 2021
- This documentation is copyrighted as part of the intellectual property of the International Virtual Aviation Organisation.
- The content of this documentation is intended for aviation simulation only and must not be used for real aviation operations.