Approach: Runway Visual Range

Question 1

What is a RVR System?

Answer 1

• The RVR system has been evolved to make available a more localised assessment of visual range in relation to a particular runway when the met report gives a visibility of less than 1,500 metres.
• The RVR indicates the range over which the pilot of an aircraft on the centreline of a runway can expect to see the runway surface markings, the lights delineating the runway / identifying its centreline.

Question 2

What are the 2 methods of RVR assessment?

Answer 2

• Instrumented RVR using electronic equipment
• Human Observer Method

Question 3

What is the UK Standard for reporting RVR in increments?

Answer 3

• 0-400m: 25m steps
• 400-800m: 50m steps
• 800-1500m: 100m steps

*Any observed value which does not fit the reporting scale shall be rounded down to the nearest step lower in the scale.

Question 4

How does IRVR work?

Answer 4

• Gives automatic & continuous display of RVR values to ATC.
• Transmissometers are used to measure atmospheric opacity from fixed points alongside a runway.
• 3 transmissometers. Touchdown, Mid-Point, Stop End.
• The system automatically allows for runway edge light intensity settings but the DEO is to be informed if an ATCO has reason to believe the runway lighting is not operating at the selected level.

Question 5

When are IRVR available?

Answer 5

• At all times unless notified otherwise.

Question 6

How do IRVR Indications work?

Answer 6

• A number of different IRVR systems are installed at UK aerodromes. The processors in some systems are programmed to automatically reduce in intensity/suppress the display of the mid-point / stop-end readings when the values are not operationally significant.
• Unless a suppressed value is specifically requested by a pilot, the RVR reports transmitted are to contain only those values that are displayed at full intensity.
• The value of the touchdown position is always displayed at full intensity & if no other values are at full intensity this is the only value which needs to be passed.

Question 7

How are IRVR Values Transmitted to Aircraft?

Answer 7

• Passed at the beginning of each approach for landing and, thereafter, whenever there is a significant change in the RVR until the aircraft have landed.
• A significant change is defined as a change in value of one increment or more.
• The current RVR value is also to be passed to aircraft before take-off.
• When all 3 positions are to be reported to the pilot, they ar to be passed as three numbers relating to touchdown, mid-point, and stop end.
• e.g. “RVR Runway 25 650 - 500 - 550 metres.”
• If only two values are to be passed, they are to be individually identified.
• e.g. “RVR Runway 25 Touchdown 650 - Stop End 550 metres”.

Question 8

What if the RVR Transmissometer Fails?

Answer 8

• The system may still be serviceable provided that confirmation is received from the DRO to this effect.
• In such circumstances the mid-point value is to be used to determine the ATC procedure and is to be passed to the pilot together with the stopend value. It is imperative the pilot be informed the touchdown transmissometer has failed.
• e.g. “RVR Runway 25 Touchdown not available - Mid-Point 600 - Stop End 400 metres”.
• If two transmissometers become unserviceable the RVR value for the remaining instrument provided that it is not the stop end value, may be used. (SWAP ENDS)

Question 9

Human Observer Method

Answer 9

• CAP168 for procedures & MATS 2
• Not from on the runway.
• Edge lights applied to a conversion table to get RVR value.

Question 10

What is the Duration of Assessment for Human Ob RVR?

Answer 10

• Met vis < 1500m
• Half hourly intervals or when significant changes of RVR occur.

Question 11

What additional info regarding RVR is good to know?

Answer 11

• Under no circumstances is an ATCO to pass a pilot info which suggests the vis is better than RVR reported.
• When pilots report a worse condition, this is to be passed.
• IRVR only works when runway lights at 10% or more.