aerodrome operating minima

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Aerodrome Operating Minima

An Effort by:Arvind Kumar Singh


References: DGCA Regulation/ICAO Docs

CAR Section 8-Aircraft Operations-Series C-Part I dated 13-6-2013-

All Weather Operations (AWO)

ICAO Document - All Weather Operations (DOC 9365)

ATMC 8 of 2013

This Civil Aviation Requirement (CAR) provides methodology of

calculating AOM-

Scheduled, Non-scheduled and General Aviation operators and

the procedure for obtaining approval of Aerodrome Operating

Minima.


Aerodrome Operating Minima Aerodrome Operating Minima is established

To ensure desired level of safety in aeroplane operations at an aerodrome by limiting these operations in specified weather conditions.

The weather limits of usability of an aerodrome for Take off- RVR and/or visibility and if necessary cloud conditionsLanding in precision approach and with vertical guidance – Visibility and/or RVR and DA/HLanding in non –precision-

Visibility and/or RVR MDA/H and, If necessary, cloud conditions.


Categories of AeroplaneVat Speed at threshold based on 1.3 times stall speed

Vso or 1.23 times stall speed Vslg in the landing configuration at maximum certificated landing mass.

Category of aircraft Speeds (IAS) at threshold (Vat) Kt

A <91B 91 to 120C 121 to 140D 141 to 165E 166 to 210

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ILS OperationsCAT I operation

DA/H 60m(200ft) Visibility 800m or RVR 550m

CAT II operation 60m(200ft) DA/H 30m(100ft) RVR 300m

CAT III operationCAT IIIA : DA/H 30m(100ft) and RVR 175mCAT IIIB : DA/H 15m(50ft) and 175m > RVR 50mCAT IIIC : No DA/H and No RVR limitations

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Low visibility procedures (LVP) Specific proceduresDuring Categories II and III approachesand/or low visibility take-offs.Low visibility take-off (LVTO)Take-off on a runway where the RVR is

less than 400 m.


Aerodrome Operating Minima -General

By Indian operators and at Indian aerodromes.• Normal AOM

• To be applied by scheduled operators. • Restricted AOM (additives of height and visibility to the normal

AOM)• By non-scheduled and general aviation operators.• By PICs when operating to an aerodrome as required by

CAR Section 8 Series O Part II Para 9.4.3.3 (a).• By PICs till they have gained command experience of 100

hours on type.


Considerations for Calculation of AOM by Airline

Type, performance and handling characteristics of the aeroplane

Composition of the flight crew, their competence and experience

Dimensions and characteristics of the runway in use

Adequacy and performance of the available visual and non-visual ground aids

Equipment available on the aeroplane for the purpose of navigation and/or control of the flight path, as appropriate, during take-off, approach, flare, landing, roll-out and missed approach

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Considerations for Calculation of AOM by Airline (2)

Obstacles in the approach, missed approach and the climb-out areas required for the execution of contingency procedures and necessary clearance

Obstacle clearance altitude/height for the instrument approach procedures

Means to determine and report meteorological conditions

Flight technique to be used during the final approach.


Commencement and Continuation of Approach (Approach Ban Policy)

Shall not commence an instrument approach if the reported RVR/Visibility is below the applicable minimum.

After commencing an instrument approach, the reported RVR/Visibility falls below the applicable minimum, the approach shall not be continued: below 1000 ft above the aerodrome; orinto the final approach segment in the case where the DA/H or

MDA/H is more than 1000 ft above the aerodrome.

After passing 1000 ft above the aerodrome elevation, the reported RVR/visibility falls below the applicable minimum, the approach may be continued to DA/H or MDA/H.

RVR is not available, RVR values may be derived by converting the reported visibility.


Non-precision Approaches.All non-precision approaches shall be flown using (CDFA)

techniqueCalculating the minima the operator shall ensure thatApplicable minimum RVR is increased

by 200m for Cat A/B aeroplanes and by 400m for Cat C/D aeroplanes for approaches not flown using the

CDFA technique, providing that the resulting RVR/CMV value does not

exceed 5000m.


Multiple RVR

The touch-down zone RVR is always controlling.

Mid-point and stop-end RVR are also controlling.

Minimum RVR value for the mid-point is 125 m or the RVR required for the touch-down zone if less, and 50 m for the stop-end.

For aeroplanes equipped with a stop-end (roll-out) guidance or control system, the minimum RVR value for the mid-point is 50 m.

The values in bold font are required for the type of operation.


CMV/Derived RVR

In cases where theRVR is not reported, a pilot may derive

RVR/CMV by using a mathematical conversion depending upon

type of approach lighting and day/night conditions.

RVR/CMV may be used to commence or continue an approach to

the applicable DA/MDA.

The minimum length of approach lights for application of CMV-

420m.


CMV/Derived RVR (2)

An Operator should ensure that a meteorological visibility to RVR

conversion is not used;

for take-off

for calculating any other required RVR minimum less than 800 m

for visual/circling approaches

when reported RVR is available

RVR is reported above the maximum value, e.g. “RVR more than 1500 metres”, it is

not considered to be a reported value of RVR.

CMV is not to be used for any RVR minimum below 800m.

May be used for a visibility minimum of 800m,

if the reported visibility is below 800m and the RVR is not reported or not available.


CMV/Derived RVR Calculation (Table 1 CAR)


Low Visibility Operations — Aerodrome Considerations

An operator shall not use an aerodrome for Category II or III operations unless the aerodrome is approved for such operations.

An operator shall verify that low visibility procedures (LVP) have been established, and will be enforced, at those aerodromes where low visibility operations are to be conducted.

PIC shall satisfy that LVPs are in force according to information received from Air Traffic Services, before commencing a low visibility take-off.


Aerodrome Operating minima - Landing

Normal Aerodrome Operating Minima

Calculated based on the latest information of airport

facilities, procedures and OCAs.

Restricted Aerodrome Operating Minima.

Restricted AOM shall be based on additives applied to the

Normal AOM as

Restricted AOM = Normal AOM DA(H)/MDA (H) + 100 ft

and normal AOM Visibility/RVR + 400 m .


Visual ReferenceA pilot may not continue an approach below MDA/MDH

unless at least one of the following visual references for the intended runway is distinctly visible and identifiable to the pilot: elements of the approach light system; threshold; threshold markings; threshold lights; threshold identification lights; visual glide slope indicator; touchdown zone or touchdown zone markings; touchdown zone lights; runway edge lights


Approach Lighting System – Class of facility


System Minima (Table 3-CAR)


Required RVR/Visibility (m) = [(DH/MDH (ft) x 0.3048) / tanα] - length of approach lights (m)

where α is the calculation angle, being a default value of 3.00° increasing in steps of 0.10° for each line in Table 5 up to 3.77° and then remaining constant.

Calculation of Minima


Failed or Downgraded Equipment – Effect on Landing Minima

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Use of RVR 750M for Cat-I operationsAn RVR less than 750 m as indicated in Table 4 may be used for: • Cat-I operations to runways with FALS, runway touchdown

zone lights (RTZL) and runway centre line lights (RCLL); or• Cat-I operations to runways without RTZL and RCLL when

an approved HUDLS, or equivalent approved system, or when conducting a coupled approach or flight-director-flown approach to the DH; or

• RNAV with approved vertical guidance approach procedures to runways with FALS, RTZL and RCLL when using an approved HUD


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Visual ApproachHigher of the associated non-precision approach minima or

minimum visibility/RVR of

2800 m for Category A/B aeroplanes,

3200 m for Category C aeroplanes and

3600 m for Category D aeroplanes.

If visual approach is requested for a runway which has only

a circling approach, the ground visibility shall not be less

than 5 Km.

May 1, 2023 25Aerodrome Operating Minima


Circling approach and the associated minima will be authorized

for Operators by Flight Standards Directorate as per the training

programme implemented by Operators.

Circling Approach


Aerodrome Operating Minima – Take off

Take-off minima expressed as

Visibility or RVR limits,

Factors for each aerodrome planned to be used and

Aeroplane characteristics.

Specific need to see and avoid-

Obstacles on departure,

Cloud base limits.


Aerodrome Operating Minima – Take off

Avoidance of such obstacles may be accomplished by

Alternate procedural means, such as use of climb

gradients or specified departure paths,

Cloud base restrictions need not be applied.

Availability of air traffic services to ensure separation of

aircraft and timely and accurate provision of weather,

NOTAM, and other safety information


RVR/Visibility for Take-off (Commercial Transport Aeroplanes)


Procedure as per ATMC 08 of 2013Ensure that “Aerodrome operating Minima” of the airport

concerned published by AAI are available in all ATC Units. Subject to provisions of the CAR, the ‘AOM ’ of Airlines may be

lower than the minima published by AAIThe current visibility and RVR and any significant changes shall be

passedWhen Visibility/RVR is at or above the AAI published Minima for

the instrument approach, the arriving aircraft may be cleared for the approach.

When Visibility/RVR is below the AAI published Minima for the instrument approach, the ATCO shall check the minima from the aircraft;

If the Visibility/RVR is above the minima reported by the aircraft, the aircraft may be cleared for the approach.

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Procedure as per ATMC 08 of 2013If the Visibility/RVR is below the minima reported by the

aircraft, the aircraft shall be asked for its intentions; If the aircraft reports intention to continue the flight for

landing.The ATCO shall issue clearance using following phraseology: CLEARED FOR (type of approach) APPROACH [RUNWAY

(number)] SUBJECT TO MINIMA. In such case, when aircraft makes an approach, a log entry shall

be made. Occurrence reporting form (Annexure A) shall be completed

by the concerned ATCO and submitted to ATS in-charge through WSO.

The ATS In-charge, after verification, shall send such occurrence report to DGCA and ED (ATM).

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Procedure as per ATMC 08 of 2013Aircraft reports intention to hold for improvement of

weather, or to divert to an alternate aerodrome,Appropriate clearances shall be issued

Visibility/RVR reduces below the AAI published Minima after the arriving aircraft has commenced approach, ATCO shall immediately pass the current visibility / RVR to the aircraft.

The aircraft is expected to follow the provisions of CAR and take appropriate actions. If aircraft reports its intention to continue approach, landing clearance may be issued at the appropriate time.

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