The document discusses procedures for air traffic controllers to follow in various contingency situations, such as: - Unlawful interference and aircraft bomb threats - Fuel dumping - Air-ground communications failure - Emergency descent - Weather deviation and VFR flights encountering adverse weather - Emergency separation and fuel emergencies For each contingency, the summary provides high-level instructions for air traffic controllers, such as clearing routes, maintaining separation, communicating with pilots and other ATC units, and directing aircraft as appropriate.

1. Actions During
ATC Contingencies
Arvind Kumar Singh
9/3/2016 1

2. Emergencies and Contingencies
• Unlawful Interference and Aircraft Bomb Threat .
• Fuel Dumping.
• Air-Ground Communications Failure.
• Emergency Descent
• Weather Deviation Procedures.
• Strayed VFR flights and VFR flights encountering adverse
meteorological conditions.
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3.  Emergency Separation
 Fuel Emergency & Minimum Fuel
 Procedures in regard to aircraft equipped with
airborne collision avoidance systems (ACAS).
 Call Sign Confusion
Emergencies and Contingencies
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4. General
 Monitor progress of an aircraft in emergency the aircraft passes out
from the coverage of the ATS surveillance system
 Inform position to all ATS units which may be able to give assistance to
the aircraft
 Transfer to adjacent sectors, when appropriate
 ADS-B emergency alert is observed & no other indication for nature of
the emergency
 Attempt to establish communication with the aircraft to verify the
nature of the emergency
 No response is received from the aircraft, ascertain if the aircraft is
able to receive transmissions by requesting to execute a specified
manoeuvre which can be observed on the situation display
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5. General
 When an emergency is declared by an aircraft, ascertain-
 Aircraft identification and type
 Type of emergency
 Intentions of the flight crew
 Position and level of the aircraft
 Decide the most appropriate type of assistance
 Enlist the aid of any other ATS unit
 Provide any other information such as details of suitable
aerodromes, minimum safe altitudes, weather information;
 Obtain POB, Fuel, any hazardous materials
 Notify appropriate ATS units and authorities as per local
instructions
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6. Unlawful Interference & Aircraft Bomb
Threat Squawk 7500/7700
 Promptly attend to requests.
 Anticipated needs of the aircraft
 Transmit, and continue to transmit, information pertinent to the safe conduct of
the flight, without expecting a reply from the aircraft;
 Monitor and plot the progress of the flight with available means.
 Coordinate transfer of control with adjacent ATS units without requiring
transmissions or responses from the aircraft.
 Inform, and continue to keep informed, appropriate ATS units, including those in
adjacent FIRs, which may be concerned with the progress of the flight.
 ATMC 9 of 2012 and Contingency Plan to deal with Unlawful Interference
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7.  If bomb or other explosive device has been placed on board-
Advise the flight crew without delay by most expeditious means.
 Ascertain the intentions of the flight crew.
Report intentions to other concerned ATS units.
Handled in the most expeditious manner, the safety of other
aircraft, personnel & ground installations are not put at risk.
Aircraft in flight shall be given re-clearance to a requested new
destination.
Taxi route shall be selected with a view to minimizing any
security risks.
 ATS units shall not provide any advice or suggestions concerning
action to be taken by the flight crew in relation to an explosive
device
Unlawful Interference & Aircraft Bomb
Threat
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8. Action by Recipient of a Bomb Threat
Ask the Caller the Following Questions
 WHERE is the bomb?
Asked first so that an evacuation can be planned.
 WHEN will it go off ?
So that a time factor is known for the evacuation.
 WHAT does it look like ?
To help in recognition of the device during a search.
 WHO are you ?
To see if the caller is from a credible group.
 WHY are you doing this ?
To build up a better picture of the incident and keep the caller on the
line to assist in tracing the call.
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9. Action When Aircraft on Ground
a) Aircraft has taxied out for departure:
Aircraft to be directed to isolation bay
b) Aircraft on bay with PIC in cockpit:
Disembark pax/crew with their handbags immediately
c) For pushed back aircraft with attached tow tractor/engine started :
Bring back acft to same stand and disembark pax with their hand
bags
d) Coaches meant for pax should be kept at least 100 m away from
the isolation bay/remote bay.
e) At the same time, the rescue, fire fighting and security services
should be alerted in accordance with the S.V.P. International Airport
emergency plan.
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10. Action When Aircraft in Air
Inform PIC complete details related to bomb threat, PIC of the acft
will take the call considering on the various merits
PIC decides to continue the flight:
 Treat acft as suspect and apply appropriate separation to ensure
that other aircrafts are not endangered.
 Keep contiguous air traffic service units informed.
PIC decides to land:
 Acft should be diverted to nearest civil or military airfield at
which it can land safely.
 BTAC decision from departing station not received
 Direct acft to isolation bay after landing
 BTAC decision from departing station received as non specific
 Direct the affected aircraft to remote/isolation bay.
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11. Fuel Dumping
In an emergency or other urgent situation to reduce to
maximum landing mass in order to effect a safe landing.
 Route should be clear of cities and towns, preferably over
water.
 Level should be not less than 6000 ft and duration of fuel
dumping.
 Separation
 At least 10 NM horizontally, but not behind the aircraft
dumping fuel;
 Vertical separation if behind the aircraft dumping fuel
within 15 minutes flying time or at a distance of 50 NM by;
at least 1 000 ft if above the aircraft dumping fuel
 at least 3 000 ft if below the aircraft dumping fuel.
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12. Fuel Dumping
• Radio silence during the fuel
dumping operation.
• Information to other ATS units and
non-controlled traffic
• Appropriate warning message for
other traffic.
• A320 , B737 aircrafts don’t have
fuel dumping system
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13. Air-Ground Communications Failure
 Squawk 7600
 Ascertain whether the aircraft is able to receive transmissions by
requesting it to execute a specified manoeuvre.
 Aircraft fails to indicate that it is able to receive and acknowledge
transmissions. Separation shall be maintained.
 In visual meteorological conditions:
 Continue to fly in visual meteorological conditions;
 Land at the nearest suitable aerodrome;
 Report its arrival by the most expeditious means to the
appropriate air traffic control unit.
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14. In instrument meteorological conditions
 In procedural separation, maintain the last assigned speed and level, or MFA if
higher, for a period of 20 minutes following the aircraft’s failure to report its
position over a compulsory reporting point and thereafter adjust level and
speed in accordance with the filed flight plan.
 In airspace where an ATS surveillance system
 Maintain last assigned speed and level, or MFA if higher, for a period of 7
minutes following
 Time the last assigned level or minimum flight altitude is reached
 Time the transponder is set to Code7600.
 Aircraft’s failure to report its position over a compulsory point.
 Whichever is later and thereafter adjust level and speed in accordance with
the filed flight plan.
Air-Ground Communications Failure
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15. Arrival at destination aerodrome:
 Proceed according to current FLP route as to designated
navigation aid/fix
 Commence descent from the navigation aid or fix or EAT
last received and acknowledged.
 If no EAT received and acknowledged than the estimated
time of arrival.
 Complete a normal instrument approach procedure.
 Land, if possible, within 30 minutes after the estimated time
of arrival or the last acknowledged EAT, whichever is later.
Air-Ground Communications Failure
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16. Emergency Descent
 Immediately broadcast by means of the appropriate radio aids, or
request for such broadcast.
 Aircraft receiving broadcast will clear the specified areas. Stand by
on the appropriate radio frequency for further clearances.
 Immediately after emergency broadcast by ACC, APP, or TOWER
concerned shall forward further clearances to all aircraft involved
 Inform any other ATS units and control sectors which may be
affected
 Attention all aircraft in the vicinity of (or at) PRA emergency
descent in progress from FL360 (followed as necessary by
specific instructions, clearance, traffic information etc.).
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17. Weather Deviation
 When appropriate separation can be applied, issue
clearance to deviate from track
 If conflicting traffic and unable to establish appropriate
separation,
 Advise the pilot of inability to issue clearance for the
requested deviation.
 Advise the pilot of conflicting traffic.
 Request the pilot’s intentions.
 Unable, Traffic West bound A320 F320 estimated PRA at 1020
call sign IGO 123 advise intentions.
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18. Strayed VFR flights and VFR Fights Encountering
Adverse Meteorological Conditions
 A strayed aircraft-
 Deviated significantly from its intended track or which reports that it is
lost
 Uncertain of its position
 Encountering adverse meteorological conditions, should be
considered to be in a state of emergency.
 Any of the following information considered pertinent so as to better
provide assistance:
 Aircraft flight conditions, Position (if known) and level, Airspeed and
heading
 Pilot experience, SSR, ADS-B capability
 Departure and Destination aerodromes, POB, Endurance.
 Assistance to a VFR flight using an ATS surveillance system upon the
request or concurrence and agreed by the pilot..
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19. Emergency Separation
 Half the applicable vertical separation minimum may be used.
 500 ft where 1000 Ft. vertical separation minimum.
 1 000 ft where 2000 ft vertical separation minimum.
 Flight crews concerned shall be advised that emergency
separation is being applied
 Informed of the actual minimum used
 Essential traffic information shall be provided
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20. Fuel Emergency & Minimum Fuel
 MINIMUM FUEL when, having committed to land at a specific
aerodrome, the pilot calculates that any change to the existing
clearance to that aerodrome, or other air traffic delays, may result in
landing with less than the planned final reserve fuel.
 Pilot reports a state of minimum fuel, the controller shall inform the
pilot as soon as practicable of any anticipated delay or that no delay
are expected.
 This is not an emergency situation but an indication that an
emergency situation is possible should any additional delay occur.
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21. Airborne Collision Avoidance System (ACAS)
 In ACAS/TCAS RA, the controller shall not attempt to
modify the aircraft flight path until the pilot reports “Clear
of Conflict”.
 The controller shall resume responsibility for providing
separation for all the affected aircraft when:
Aircraft has resumed the current clearance.
Aircraft is resuming the current clearance and issues
an alternative clearance is acknowledged by the flight
crew.
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22. Procedure for reporting RA’s
 Reports made by aircraft on RA shall be entered in the log
book and Inform WSO and ATS In-charge
 Reports of RA shall be reported by signal to M(O) / ED
(ATM) / GM (SQMS)
 In-charge of ATS units shall investigate the incident and
take further action in consultation with GM(SQMS)
 Complete an Air Traffic Incident Report.
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23. Call Sign Confusion
Use of similar call signs by aircraft in the same area on the same RTF
frequency often gives rise to potential and actual flight safety
incidents.
 Such call sign confusions often lead to incidents
 Airprox, loss of separation, loss of communication, blockage of
transmissions
 level bust, runway incursions, Controlled Flight Into terrain
(CFIT), increased workload for both pilots and controllers
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24. Consequence
 Takes up a heading or routing intended for another
aircraft
 Climb or descent to a level to which is not cleared
 Leaves RTF frequency
 Blocks a transmission from theintended recipient
 intended recipient does not receive the clearance, and
fails to take clearances
 Misunderstands the intentions of aircraft
 Issues a clearance to the wrong aircraft, and/or fails to
issue a clearance to the intended aircraft
 Increased workload of controllers and pilots
Call Sign Confusion
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25. Measures
 Observe correct RTF discipline
 Pronounce call signs at a lower speed and more clearly
 Do not clip transmissions.
 Do not use readback time to execute other tasks.
 Ensure clearances are readback correctly. Correct any error in
read-back.
 Caution when language difficulties may exist.
 Use headsets especially during periods of high workload
 Actively monitor flight crew transmissions and compliance
 In Blocked transmission ensure that both aircraft retransmit
and receive correct clearance
Call Sign Confusion
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26.  Email following information to
report_callsignconfusion@aai.aero
 Date and Time
 Sector or geographical location
 Call signs of the aircraft concerned
 Phase of the flight
 Change Your Call Sign to (new call sign) [until further
advised]
 Revert to Flight Plan Call Sign (call sign) [at (significant
point)]
Call Sign Confusion
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