Visual Landing Aids

Question 1

Describe the purpose of approach lighting systems

Answer 1

Approach lighting systems help the pilot to transition from instruments to visual cues to a landing on an instrument approach

The approach lighting system allows the pilot to continue the approach below decision height until the geometry allows the pilot to see the runway.

Question 2

Describe the purpose of circling guidance lighting and runway lead-in lighting.

Answer 2

CGL - used when existing approach and runway lighting systems don’t satisfactorily permit identification of the runway or approach area to a circling aircraft.

Used, where terrain or obstructions restrict the circuiting area, or where the need exists to provide a clear indication of the landing threshold during the latter part of the downwind leg, the base leg or on the final approach.

RLLS - provided where it’s desired to provide visual guidance along a specific approach path, for reasons such as avoiding hazardous terrain or for noise abatement. They may also be used to provide take-off flight path guidance.

Question 3

Describe characteristics of circling guidance lights

Answer 3

High intensity amber lights are used to identify and locate the landing threshold during the later part of the downwind and on base leg.

All lights are elevated 6º above the horizontal as to be visible in the appropriate areas of the circuit.

Question 4

Describe how PAPI works

Answer 4

Each PAPI installation is made up of individual PAPI boxes, each containing a light source and several lenses.

Light is produced by a bulb at the back of the box. Half of the light is passed through a red filter.

The light then passes through the lens and out at a set angle so that approximately half of the light produced is white, with the(lower) half red.

Above the preset angle the pilot sees white, below it they see red.

Question 5

What’s a full PAPI

Answer 5

PAPI which consists of four individual PAPI boxes located to the left of the runway touchdown zone, each set at different angles with lowest being farthest from the runway.

Question 6

Describe the different light indication on PAPI

Answer 6

4 whites - too high
3 whites 1 red - slightly high
Half n half - on slope
3 red 1 white - slightly low
4 reds - too low

Question 7

What’s a double sided PAPI

Answer 7

Basically a full PAPI but double sided to provide a form of horizon line.

Question 8

What’s an abbreviated PAPI

Answer 8

PAPI where it only uses two boxes. Still gives the pilot an on slope indication but not how far away from the slope they should deviate from.

Question 9

Light indications on APAPI

Answer 9

2 whites - above slope
Half - on slope
2 reds - below slope

Question 10

Explain the standard PAPI angle setting, and the setting of PAPI threshold crossing height (TCH) and visibility.

Answer 10

PAPI should be visible 4nm from threshold when on centreline and 5º in azimuth.

Angle - typical PAPI angle 3º, 4 boxes will range from 2.5º to 2.83º to 3.17º to 3.50º. A range of 0.34º

TCH help guide aircraft to achieve an acceptable wheel height crossing the threshold. TCH can be found under the aerodrome operational data under lighting.

Question 11

What is a VASIS and how is it read?

Answer 11

Old type of approach slope indicator consisting of two pairs of light boxes located on each side of the runway touchdown zone.

4 white lights - above slope
2 white, 2 red - on slope
4 red - below slope

Question 12

Describe T-VASIS (visual approach slope indicator system)

Answer 12

The T-VASI installation consists of two horizontal wing-bars, with four lights each, positioned one either side of the runway touchdown zone.

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Question 13

Describe the lights on a T VASIS

Answer 13

Full inverse T - very high
Partial inverse - slightly high
Horizontal line - on slope
Partial T - slightly low’
Full T - low
Full T + Red - very low

Question 14

State the possible atmospheric effects on approach slope indication.

Answer 14

Airfields near the coast suffer from salt spray obscuring the lens of PAPI’s. This not only reduces the range but can make the lights appear a pink colour with little definition between the red and white.

Some surfaces surrounding the lights (the backdrop and foreground) can also make it difficult to focus on the PAPI indications (e.g. long grass).

Question 15

What do Runway threshold lights, end lights, edge lights, centreline, end identifier and displaced lights look like

Answer 15

RTHL - unidirectional green in direction of approach located across the runway end between the runway edge lights at the landing threshold

RENL - unidirectional RED lights toward an aircraft taking off at the departure threshold.

REDL - omni-directional white lights on sides of runway.

RCLL - white lights on the centreline, smaller lights, with 914m remaining they r transition to white and red and 300m remaining they are fully red.

REIL - high intensity uni-directional light projectors located on either side of the runway approx 30m from the runway centreline and line with the landing threshold. They flash at a rate of 60 per minute

Displaced threshold - indicated by two green wing bars either side of the threshold and red edge lighting prior to displaced threshold.

Question 16

What do taxiway edge lighting, centreline lighting, runway guard lights, stop bar lighting and intermediate holding position look like.

Answer 16

Taxiway edge - fixed omni-direction lights showing blue

Taxiway centreline - omni-directional lights showing green, should provide continuous guidance from the runway centreline to a point on the apron where the aircraft leaves the taxiway for a stand, gate or other location.

Runway guard - two elevated amber lights that flash alternately, they operate continuously with the purpose of warning pilot they’re entering active runway.

Stop bar - located at taxiway holdpoints. Consisting of uni-directional RED lights facing the holding aircraft. Must not proceed unless lights are gone and they have clearance.

Intermediate holding position - lit with three amber lights, centre light is Omni-directional, while left and right are uni-directional.

When approaching from the holding side of the intermediate holding position, the pilot will see three amber lights.

When approaching from the other side, the pilot will see a single amber light, indicating to them where the holding position so that they know when they’ve passed it.

Question 17

What do windsock, obstruction and hazard beacon lights look like?

Answer 17

Windsock - just a normal windsock thats illuminated

Obstruction - a red omnidirectional light for any obstacle which extends into the obstacle protection surface. E.g control towers, VOR

Hazard beacons - common for significant terrain around approach or circuit area, can be found on aeronautical charts represented as stars and on operational data in the AIP under lights.

Question 18

What are the different lighting characteristics in aerodrome operational data? (F, FLG, GpFLG, OCC, ALTN)

Answer 18

(F) Fixed - light is continuous and steady
(FLG) Flashing - periods of light in a given time is shorter then periods of dark
(GpFLG) group flashing - group number of brief flashes
(OCC) Occulting - intermittent lights with periods of darkness shorter then periods of light
(ALTN) Alternating

Question 19

Aerodrome beacon lights why is it used and its characteristics

Answer 19

An aerodrome beacon must be provided at an aerodrome intended for use at night if one or more of the following conditions exist:

Aircraft navigate predominantly by visual means.
Reduced visibilities are frequent.
It is difficult to locate the aerodrome from the air due to surrounding lights or terrain.

Characteristics:

Like a lighthouse, located on top of control tower, or tall building. Location is found on both VNC and on aerodrome plate by a star. Typically a beacon will flash between 13-20 times per minute.

Question 20

Describe pilot activated lighting (PAL) and the standard system of keying PAL.

Answer 20

Activation - Five rapid and short transmissions, collectively not exceeding three seconds.

Brilliance and runway selection - After a 10 second warm up when first turned on, the lights switch to full brightness. To change intensity, repeat the activation sequence but hold the button down on the last transmission.

The lighting intensity will continuously cycle until the transmit button is released. Where alternative runways are available the cycling will include changing to the next runway(s) and cycling their brilliance before starting the cycle again.

Other aerodromes may have daylight sensors which automatically adjust the brilliance of the lighting in response to the amount of ambient light the sensors are receiving. In this case, the pilot cannot manually adjust the brilliance.

Re-activation - At any time a single transmission will reset the lighting timer for a further 20 minutes. Note: There is no warning prior to the lights turning off.

Question 21

Describe the means available for remote control of lighting other than PAL

Answer 21

Outside ATC hours of service, lights of many controlled aerodromes can be controlled remotely by radar controllers.

Activation and changes to intensities may take up to 1 minute to action and it is suggested that you give the controller as much notice as possible if you will be requiring them to activate the lights.

Go in operational Data to contact aerodromes ahead of time.