Unit-5-ATC & Aerodrome Design 1401 VISUAL AIDS FOR NAVIGATION, VISUAL AIDS FOR DENOTING OBSTACLES EMERGENCY AND OTHER SERVICES

Syllabus Visual aids for navigation Wind direction indicator – Landing direction indicator – Location and characteristics of signal area – Markings, general requirements – Various markings – Lights, general requirements – Aerodrome beacon, identification beacon – Simple approach lighting system and various lighting systems – VASI & PAPI - Visual aids for denoting obstacles; object to be marked and lighter – Emergency and other services.

Visual and Nav Aids Visual aids for navigation Wind direction indicator – Landing direction indicator – Location and characteristics of signal area

Runway of Chennai Airport

Chennai Terminal

Chennai Airport Specification Location Trisoolam;MSL=16m Bearing=12*59’N 80*E Runway 1. 07/25; 3.658m Asphalt Runway 2.12/30; 2.05m Asphalt/Concrete

Visual Aids for Navigation Stop Bars on Domestic and International runways Parking stand with center line lighting system Instrument Landing system (ILS) During Day time: Windsocks, Windpipe, During Night Time: Beacon lights

Wind direction Indicator-Windsock/Wind cone

Wind direction indicator-Windsock Pilot check windsock or Wind Tee or Tetrahedron Wind direction indicators include a wind sock, wind tee, or tetrahedron. Located in a central location near the runway and may be placed in the center of a segmented circle identifying the traffic pattern direction, left-hand pattern. The windsock a good source of information since it not only indicates wind direction, but also allows the pilot to estimate the wind velocity and gusts or factor. Windsock extends out straighter in strong winds and will tend to move back and forth when the wind is gusty. also look at the windsock, if available

Visual Aids for Navigation

Wind cone or Windsock Weather resistant man-made fiber, impregnated fluorescent orange, mounted on a ring, attached to a bearing mounted, free rotating counter balanced assembly on a steel tubular column. Column: galvanized column raised or lowered by means of a lifting lever associated with a spring counter balance unit. Floodlights4 x 80W sealed beam floodlights. Obstruction Lights One ZA753/6 double obstruction light c/w automatic lamp with changeover relay. GlasswareTwo red glass domes for ZA753/6.Made of Handmade Fiber

Wind cone Construction

Wind Tee & Tetrahedron and Wind tees and tetrahedrons can swing freely, and will align themselves with the wind direction. TETRAHEDRON- A device normally located on uncontrolled airports and used as a landing direction indicator. The small end of a tetrahedron points in the direction of landing. The tetrahedron indicating wind direction by pointing into the wind The wind tee and tetrahedron be manually set to align with the runway in use;

Tetrahedron for Wind Direction

Tetrahedron

Wind direction Indicator

Wind Direction Indicator

Aerodrome beacon, identification beacon Nav Aids and Beacons Aerodrome beacon, identification beacon

Landing Direction Indicator A device to pilots indicating visually aircraft direction designated for landing or takeoff.

Landing Direction Indicator

Types of Landing based on Visibility Cat I landing: < 800 m Visibility on precision approach Cat II Landing: = 350 m visibility Precision instrument approach Cat III Landing: = 200 m visibility divided into Cat III A(100m), Cat III B (50m) and CAT III C( 0m)

5 Phases of Approach on ILS Arrival Initial Approach of flight for aligning the aircraft for FAF-Final Approach Fix to the Runway Intermediate approach for complex approach Final Approach-4 to 12 nm @2.5 to 6* Missed approach- an optional case in case of VFR not obtained

Five Phases of Flight for ILS Arrival: Pilot navigates to the Initial Approach Fix . Initial Approach:Pilot commences the navigation of the aircraft to the Final Approach Fix (FAF), a position aligned with the runway, Intermediate Approach: an additional phase in more complex approaches that may be required to navigate to the FAF. Final approach: between 4 and 12 nms of straight flight descending at a set rate (usually an angle of between 2.5 and 6 degrees). Missed Approach: an optional phase; VFR not have been obtained at the end of the final approach, this allows the pilot to climb the aircraft to a safe altitude and navigate to a position to hold for weather improvement or from where another approach can be commenced

Decision Height A decision height (DH) - the safe height to the Pilot for Climb in the precision approach when required VFR reference to continue the climb has not been acquired. A specified height above the ground in an instrument approach procedure & expressed in feet above ground level.

Descent Altitude

Decision Height

Airport Characteristics

Instrument Landing System

Instrument Landing System A precision approach guidance system providing precision guidance to aircrafts approaching and landing on a runway Consist of Localizer, Marker Beacons and DME Using combination of radio signals and high-intensity lighting arrays for a safe landing during low ceilings or reduced visibility due to fog, rain, or blowing snow Aircraft guidance provided by the ILS receivers fitted in the aircraft

Localizer Array

Localizer An Array of directional antennas fitted at the end of the runway Two signals transmitted on carrier frequency range 108.10 MHz and 111.95 MHz & modulated at 90 Hz & at 150 Hz and transmitted from separate antennas. Each antenna transmitting a narrow beam, one s to the left of the runway centerline & the other to the right Depth of modulation at the Loc RX indicate the aircrafts position ( m=0, aircraft at the centerline)

ILS — Localizer

Localizer Antenna Path

ILS — Glideslope

ILS Localizer beam width = 3 to 6* ILS use a second beam a "glide slope" beam giving vertical information to the pilot. -glide slope usually 3° wide with a height of 1.4° . A horizontal needle on the VOR/ILS head indicates the aircraft's vertical position

Glidepath

Glidepath

Airport Beacon A device located at the airport to attract attention; mounted on the top of control tower, above other buildings of the airport. Producing flashes. most effective from one to ten degrees above the horizon Flashing Xenon Strobes @ Rate-24 to 30 per minute with lighted green and white color

a. Airport Beacon

b. Rotating beacon

Marker Beacons A particular type of VHF radio beacon used in aviation in conjunction with an instrument landing system (ILS), to give pilots a means to determine position along an established route to a destination such as a runway. they have become increasingly limited to ILS approach installations

Marker Beacons at the Runway 3 marker beacons (outer, middle and inner) located in front of the landing runway and indicate their distances from the runway threshold. Outer Marker (OM) = 4 to 7 miles from the runway. Middle Marker (MM) = about 3,000 feet from the landing threshold, and Inner Marker (IM) = between the middle marker and Runway threshold

Markers

Markers WHITE Low Visibility AMBER Low Visibility With Missed Approach BLUE Before A Final Approach

Marker Beacons OM-Blue-400 Hz- MN-Amber-1300 Hz- for low visibility with missed approach IM-White-3000 Hz-low visibility condition

Aerodrome Locations

Aerodrome Locations Runway –Main and Secondary Terminal Building Control Tower Taxiway Holding Points Serving Area Sterile Area Barrier

Various Aerodrome Locations Main Runway( most frequently used depending on Wind direction) & Secondary Runway (when wind changes the direction) Terminal Building ( for holding passengers and for immigration and customs) & Control Tower ( a building with good visibility for aircraft maneuverability) TaxiwayLights- a link between Runway and diff parts of airport(terminal and hangars), marked by yellow lines Holding Points ( a place where aircrafts stopped on the taxiway for permission from Control tower to proceed to the runway). and Servicing Platform Servicing Area: Aircraft Servicing Area-An area reserved for pre and post flight operations between two flights.

Runway Markings Threshold: marked by a line of green lights-Four stripes on either side of the centerline at the end of the runway Magnetic Runway Heading-29- number, to the nearest one-tenth of Magnetic North Landing aiming point a visual cue, it is generally 1,000 feet from the threshold Touch Down Zone Markers:Meant to help define the touchdown zone, they show distance information in 500 foot increments Distance to go Markers:number denotes the distance remaining, in thousands of feet. Runway Designator Sign:the departure end of runway 9 is to your left and the departure end of runway 27 is to your right.

Define: Runway Number Whole number nearest one-tenth (degrees divided by 10 rounded) of the magnetic azimuth of the runway centerline, measured clockwise from the magnetic declination Runway 36 would be aligned in roughly a 360 degrees direction (magnetic north), Runway 9 would be used for a runway with a 90-degree alignment .

Runway Number

Runway Number Runway number is one tenth of the runway centerline's magnetic azimuth, measured clockwise from the magnetic declination Runway number between 01 and 36 Runway Number indicate runway's heading A runway - 36 –Pointing 360* north Runway 09 points East = (90°), Runway 18 south (180°), and Runway 27 points west (270°).

Holding Point

Various Aerodrome Locations Sterile Area-Beginning of the Runway where no aircraft can be parked Barrier- A safety net to the stop the aircraft during emergency Windsock (Bright Orange Tubes to indicate Wind Direction) and Arrestor Gear( a cable stretched across the runway for emergency) Airfield Identification- A Square Signal that can be seen from the air.

Taxiway Lights

Designation on the Taxiway designation of the taxiway on which the aircraft is located. These signs are installed along taxiways either by themselves or in conjunction with direction signs or runway holding position signs.

Chennai Airport

Airport Lighting & Aids Lights, general requirements –– Simple approach lighting system and various lighting systems – VASI & PAPI - Visual aids for denoting obstacles; object to be marked and lighter – Emergency and other services

Runway Lighting

Airport Lights Ground lights for precision approach -6 direction and 24 direction;Runway lighting-touch down, centre line, end lights-VASI & PAPI ( Visual approach and precision approach) Taxiway lights Beacon lights for Airport Identification= Signaling lighting at Control Tower

Airport Lights

Runway Lights Listing, Color,

Listing Approach Lights-6 direction and 24 direction Threshold Lights-green lights extending to runway edge. Touch down Zone Lights-High intensity lights extending to 600 m of Threshold Centerline lights-embedded 15m interval white lights Edge Lights-White color lights Runway End Lights-4 Uni-directional Red color lights Taxiway centerline Lights

Airport Lighting

Color Strobing White-Omnidirectional Approach Lights- strobing towards the threshold Threshold lights- unidirectional green extending to Runway Edge Centerline-White color light; Touch Down Lights- Edge-White color lights; Runway Threshold-Green Red or Red-Red ; Taxiway Centerline-Green –Green

APPROACH LIGHTs

Runway Lights from Approach to

1.Various Lights at Runway Edge Lights Threshold Lights Center line Lights End Lights Touch Down Zone Lights Runway Guard Lights

Threshold and Touch down Lights

4. Touchdown Zone Lights

Touchdown Zone Lights

Runway edge lights

3. Runway Centerline Lights

Simple Runway Approach lighting Omni-Directional Approach Lights used to identify the approach end and centerline of the runway Horizontal Bright beam pattern flash sequentially strobing rolls toward the runway threshold Strobing flash helps the pilot to identify the runway in use Strobing 60 Flash/Minute,360* Hori and 8* Vertical Beam

Runway Centerline Light Strobing Runway light towards Threshold-White White 60 Flash/Minute

Simple Approach Runway lighting system Centerline Lights:Row of lights on the centre line of runway and displaced 900 m from runway threshold. Approach lights placed at 30 m from the threshold & has two crossbar lights.First crossbar light been placed 150 m away from the threshold. Second crossbar been placed 300 m away from the threshold Threshold Lights are Green Ground Lights Edge lights distributed symmetrically on both sides of the runway at 60m intervals End of Runway Lights-Red Taxiway Lights-Blue Lights

Operation of Approach Lights Operational from sunset to sunrise Operational from Sunrise to sunset on visibility <3000 m Operational when requested by pilot Operational at any other time based on weather conditions, & when desirable for the safety of air traffic Operational when the associated runway lighting is operated.

Runway edge lights Operational on the edges of runways during darkness and at poor visibility @ 60 m intervals 3 Types of Edge lights :1. High Intensity Runway Lights (HIRL)2.Medium Intensity Runway Lights (MIRL) & 3.Low Intensity Runway Lights (LIRL) Edge Lights are white in colour

Centerline Lighting Used for Steering the Aircraft to the centerline High Power LED, can withstand high windspeed of 160 mph White for the First path of the Runway, Alternate White and Red Light embedded on the runway for 600m and Red for the last 300m @ 15 m intervals

Centerline lights (first R & W and last R) @ 15m

3. Runway Centerline Lights

Touch Down Zone Lights White Lights Bars on either side of the Centerline 3 White Lights in Each Row upto 900m or the midpoint whichever is less on either side of the centerline lights

Threshold Lights Red & Green lights located at the end of the Runway Red for Departure to Pilot and Green for Landing to Pilots

Taxiway Lighting For Pilots to get off the runway as fast as possible Green color(centre line) lights at 15m intervals Consisting of Edge Lighting(Blue), Centerline Lighting (green),

2.Taxiway lighting

Runway Guard Light

Runway Guard Lighting

Approach Lighting System VASI & PAPI

Approach Lighting System

Approach Lighting System Visual Approach Slope Indicator-VASI Precision Approach Slope Indicator-PAPI

VASI Visual Approach Slope Indicator A system of Lights ( White and Red) arranged for descent guidance information Visible at 5-8 KM at day and 25 KM at night, providing safe obstruction clearing within +/-10* of the centerline of the extended runway VASI initiated only when theAircraft visually aligned with the Runway VASI arranged in BARS as Rear, Middle and Far Grouped as 2 Bar( near and far) & 3 Bar ( near, middle and far) VASI minimizes the possibility of undershooting or overshooting the designated touchdown area.

Principle Color differentiation between Red and White on Glide path 3 situations 1.above the glide path, 2.on Glide path and 3. below glide path All White when Glide path slope High Red & White bar on Approach Slope All Red when Slope is low

Schematic

2 Bar VASI Far Bar Far Bar Near Bar Near Bar Above glide path Below Glide path On Glide path Red Illumination White Illumination

VASI

Tutorial Draw the schematic of 3 Bar Vasi showing the illumination of lamps

Precision Approach Path Indicator-PAPI Principle, Schematic

PAPI A Safe, accurate Glide Approach system for the Pilot Located on the left or right side of the runway at 90˚ to the runway centre line spaced at 9 meters apart in Boxes, 300m away from the Landing Threshold PAPI indicates the aircraft position wrf to glidepath; too high or too low wrt white color light or red color light to the Pilot VISIBLE up to 8 KM during the day and 25 KM at night using a 2 Lamp Papi. Lamps are adjusted to the correct glide slope angle (± 3' of arc) Made of LEDs with lifetime operation of 50,000 hours

Alsthoms PAPI-4 Box light system

View of PAPI

PAPI (Precision Approach Path Indicator)

PAPI-Precision Approach Path Indicator Precision Approach Path Indicator (PAPI) -a light system positioned beside the runway consisting of two, three, or four boxes of lights giving visual indication of an aircraft's position on the glide path for the associated runway. An instrument helping to carry out a correct approach (in the vertical plane) on an aerodrome Located 300 meters beyond the landing threshold of the runway. PAPI seen to the right of the runway. More number of red lights visible means the aircraft is below the glideslope.

4 Bar Papi

PAPI

PAPI

PAPI seen to the right of the runway with number of red lights visible means that the aircraft is below the glide slope.

PAPI-4 BOX LIGHT SYSTEM Precision Approach Path Indicator (PAPI) a system of ei four or two identical lights Light box assembly consist of a stable optical platform supporting the lamp, reflector, lenses, color filter, and tilt switch. Light from the lamp collected and focused to a convex lens set producing the field of illumination into the approach area. Units placed on the left of the runway aimed outward into the approach zone on a line parallel to the runway. Front face of each unit is perpendicular to the runway centerline.

Advantages Outstanding photometric performance. Four-leg design makes each light housing assembly very stable reducing maintenance and increasing airfield utilization Quartz halogen lamps with rated life of 1200 hours. A wireless remote control system obviates the need for long runs of control wire to distant PAPIs

Obstructions at Airport

Use of obstacle lights High-intensity obstacle lights are intended for day use as well as night use. Low-intensity obstacle lights, Type A or B, shall be used where the object is a less extensive one and its height above the surrounding ground is less than 45 m. Low-intensity obstacle lights, Type C, shall be displayed on vehicles and other mobile objects excluding aircraft. Medium-intensity obstacle lights, Type A, B or C, shall be used where the object is an extensive one or its height above the level of the surrounding ground is greater than 45 m.

Obstruction Lights Terminal Building Hangers

Effects of Obstacles near the Aerodrome Limiting the distance available distance for take-off and landing Poor visibility and temperature affecting the operations of flight into or out of an aerodrome. Tall Structures near the Airport affect a fully loaded aircraft with slow climbing rate Signals received by aircraft from Tall installations and Structures located close to aeronautical installations distort the signal, Heights of structures must therefore be controlled in order not to penetrate these areas of the airspace

Obstruction Lights Airport beacon-airport beacon normally located within 5,000 feet of the airfield Identification or code beacon- identifying airfield where the airport beacon is more than 5,000 feet away from the airfield Obstruction beacon-indicating the visual identification of natural obstacles or structures 45 meters above airfield elevation for hazards like towers, buildings, tall bridges, communication towers etc .

b. Identification Beacon

b. Identification Beacon Flashing Night Visibility 15 Miles 120V, 250 W Metal Halide Bulbs used ( 3-5 Years of life)

c. Obstruction Lamp

c.Obstruction lights Working voltage from C85V to 260V Anti-bounce, corrosion proof, anti-lightening strike ,easy to install. with four synchronous flash control methods to select rated power waste 　110W light color options 　 red, green and white level of protection 　IP65

Obstacle lights when heights less than 45’