Three lane procedures on Apron - ACI Objective. To provide the ...

THREE LANE OPERATIONS ON APRONCaptain Samir Kohli, NMHead – Aviation Safety

ObjectiveTo provide the participants with an overview of the<strong>Three</strong> taxi <strong>lane</strong> operations on the Apron of BengaluruInternational Airport including the problemsencountered in design and operations along withsolutions implemented.

Purpose of <strong>Three</strong> <strong>lane</strong> taxi system• Growing Air traffic• Enhances capacity• Reduces flight delays• Lowers infrastructure cost

ACI Apron Markings and Signs Handbook

Internal Discussions• Need for three taxi-<strong>lane</strong>s considered essential to beable to meet anticipated traffic within the given areaof apron.• Recognized as a “Capacity Enhancement measure”,needing an aeronautical study including a „Hazard andRisk mitigation exercise‟.• Involvement of Pilot groups and Air Traffic Managersconsidered essential for proper decision making.• Safety Action Group (SAG) formed chaired by AirportsHead – Aviation Safety to conduct the study, carry outhazards and risk mitigation and obtain approval fromthe DGCA (Aviation Regulator)

Aeronautical Study• Included experts in the fields of Airside operationalmanagement, apron management, air trafficmanagement, airport certification auditors, aircrewcertification inspectors, fleet commanders from 3 majorcarriers (each with >25% market share), GHAs, FlightCaterers, Into p<strong>lane</strong> Fuelling agents and cargo operators.• Met seven times over 14 months.• Carried out a detailed study of traffic projections,parking stands requirements and international standards& recommended practices for Apron construction as wellas operations.• Detailed hazard identification and risk analysis, usingICAO matrix.

ICAO SARPs• An 14 Section 5.2.8.1: Taxiway centre line marking shallbe provided on a paved taxiway, de-icing/anti-icing facility andapron where the code number is 3 or 4 in such a way as toprovide continuous guidance between the runway centre lineand aircraft stands.• Doc 9157 Part 4 Section 2.3.12: “…primary line should be forthe most critical aircraft, i.e. the aircraft requiring thegreatest maneuvering area.”• Doc 9157 Part 4 Section 2.3.13: The guide lines shouldnormally be continuous solid yellow lines at least 15 cm, butpreferably 30 cm, in width. However, where a secondaryguide line is provided, it should be a broken line todistinguish it from the primary line. Additionally, the type ofaircraft that is to follow each line should be clearly indicated.

Result• Accepted the need for three taxi <strong>lane</strong>s.• Pilot groups unanimously disagreed with ACIrecommendations on use of Orange and Blue color ongrounds of poor wet pavement visibility of these colors.• Recommended only yellow color markings with embedded1.9µ refractive index glass beads and black border.• Recommended broken lines for Code C and below andcontinuous line for Code D/E aircraft.• Recommended Nose-wheel-over-line type of markings,specifically Coat Hangar type of marking, for all aircraft onargument of airports legal liability to provide wing tipseparation guidance up to stand stop bar.• Recommended use of Multi user stands.

Final design of apron recommendedL1 L2 L322 M22 M26 M26 M16 M65 M16 M36 M 36 M8 M 8 M8 M

Apron as built (1/2)Phraseology: “Turn left/right on L1/L2/L3 for stand …”“taxi to stand … Via Left/Right on L1/L2/L3”“Left/Right for stand …. Via L1/L2/L3”Use of “TO” prohibited after L1, L2 or L3 to avoidconfusion with “TWO”

Apron as built (2/2)

Some Pictures

Operational ConceptHDCode D/EstandsCode CstandsInitial designation of TL1/TL2/TL3 was revised to L1/L2/L3 on therequest of Air Traffic service provider, Airports Authority of India.

Wing span limitations and Lanedesignations

Operational Problems• Aircraft missing right turn to Link „H‟ while taxiing out of theApron and therefore continuing into cargo apron.• Code C Aircraft taxiing into neighboring Code D/E stands.• Pilots report difficulty in estimating turn path over curved lines.• Night visibility of lines during heavy rain.• Push back separations and illusions.

Aircraft missing turn to link „H‟

Code C aircraft entering neighboring CodeD/E stands (1/2)EARLIERNOW

Code C aircraft entering neighboring CodeD/E stands (2/2)EARLIERNOW

Estimating turn path over curvesChanged from 2 m line - 2 mgap to 3 m line - 1 m gap

Night visibility of lines during heavy rains• Continues to be a problem area.• Centre line lighting being contemplated.• Progressive centre line lighting not possible on a threetaxi <strong>lane</strong> apron due complexity of traffic movementand MARS.• We look at centre <strong>lane</strong> lighting in Blue color overyellow <strong>lane</strong>s.• Point in debate: Multicolor lines as recommended byACI along with respective color lights i.e. Orange,Yellow and Blue instead of only Blue.

Push back separations and illusions• Calculation of push back separations is a complicated process withMARS. Initially flight delays encountered as maintaining 80 mbehind Code C and 250 m behind Code D/E aircraft translated toblocking 5 and 11 stands respectively.• Solution found by permitting aircraft to cross from L1 to L3 withguidance of a follow-me vehicle.

Promulgation• AIP (India) supplement• NOTAM – Code C aircraft to remain on broken linesonly on the Apron. Code D/E aircraft should neverattempt to follow a broken line.• Interacted with Jeppesen for correction to aproncharts published by them.• Pilot guidance handbook published and circulated toairlines for pilot briefing• Direct interaction with Airlines Safety departmentsand Flight Dispatchers to ensure standard pilotbriefing content modified.

Standard development• Color of Taxi Lanes. Issue of wet pavement visibility ofOrange and Blue colors Vs Yellow needs to be scientificallyaddressed.• Centre line lighting on a three <strong>lane</strong> apron should be astandard. Progressive lighting is not possible.• VDGS installation on a three <strong>lane</strong> apron should be astandard.• Specification of broken lines on a curve: ICAO 2 m line – 2m gap. We recommend: 3 m line, 1 m gap.• Do we really need nose-wheel-over-line markings? If so,are Coat Hangar type markings suitable for Code C andbelow aircraft or are they required only for Code D/Eaircraft? How then can we merge that into a MARS typeapron? Why not have just a straight line to stand?

Thank You03 March, 2009