Bomb Warning: Guidance for Controllers

Bomb Warning: Guidance for Controllers


This article provides guidance for controllers on what to expect when dealing with situation involving an aircraft which reports or is informed by ATC that it may have an explosive device on board. There are some considerations which will enable the controller not only to provide as much support as possible to the aircraft concerned, but also maintain the safety of other aircraft in the vicinity and of the ATC service provision in general.

Useful to Know

A bomb threat regarding an aircraft is one of the contingencies air traffic controllers should be prepared to manage. Although historical evidence shows the vast majority of bomb threats are false, all received bomb warnings must be considered real and ATCOs must be ready to manage such situations for the protection of human life and property.

Anticipated Impact on Crew

A wide range of practical problems could arise following bomb warning:

  • Increased workload in the cockpit - Upon receiving a threat for an explosive device on board, the flight crew normally assesses the situation and depending on the stage of flight and whereabouts of the aircraft, the crew makes a decision how to continue the flight.
  • Possible high level of stress - Although the flight crew can be expected to appear to remain calm, high levels of stress are normal and should be expected due to the nature of the contingency.
  • Possible communication problems - non standard RTF can be anticipated in the course of communications from the flight crew to ATC.
  • Decision for emergency evacuation - the flight crew may take the decision for emergency evacuation on the runway immediately upon landing.
  • Least Risk Bomb Location - If a specific suspect package is identified on board an aircraft, the aircraft commander may decide that it should be moved to the designated least risk bomb location, usually next to an external door in the rear galley. Such a decision may or may not become known to ATC at the time but such an action should expect to be communicated prior to landing.

Suggested Controller’s Actions

What to Expect

As a controller, one can expect that pilots who become aware of a bomb threat will request:

  • To stop climb and/or descend if the aircraft is climbing.
  • Immediate flight level (FL) re-clearance, usually to lower FL
  • Landing at the nearest suitable aerodrome
  • Information about such aerodromes such as runway in use, runway length, runway surface, aerodrome elevation and approach aids and frequencies.
  • Bomb intimidation could be communicated by a passenger(s) already on board of the aircraft. Historically such threats were also caused by drunk and unruly passengers which were often pacified by members of the cabin/flight crew. In such cases law enforcement and medical response would be required after landing.

Other unexpected requests may also be made as a result of co-ordination with other agencies.

A TWR/APP controller should expect the aircraft to be put into landing configuration earlier than usual and track miles should never be minimised unless this is expressly requested. Do not allow a missed approach to become necessary because of ATC reasons.

What to Provide

Best practice embedded in the ASSIST principle could be followed (A - Acknowledge; S - Separate, S - Silence; I - Inform, S - Support, T - Time):

  • A - acknowledge the bomb warning, ask for intentions and provide information regarding next suitable for landing aerodromes as necessary;
  • S - separate the aircraft and if necessary prioritise it for landing, allow long final if requested, keep the active runway clear of departures, arrivals and vehicles;
  • S - silence the non-urgent calls (as required) and use separate frequency where possible;
  • I - inform the supervisor and other sectors/units concerned; inform the airport emergency fire rescue services and all concerned parties according to local procedures; as tower controller expect airport authorities to execute their bomb threat emergency plan.
  • S - support the flight by providing any information requested and necessary such as type of approach, runway length and any additional aerodrome details, etc.
  • T - provide time for the crew to assess the situation, don’t press with non urgent matters.


To mitigate the effect of bomb emergencies, the following additional guidelines should be followed by ATCOs dealing with bomb warning situation.

When informed by the crew about bomb threat on the aircraft, be ready to:

  • Clear airspace in the immediate vicinity, provide adequate horizontal and vertical separation between the aircraft with explosive device on board and other traffic
  • Try to vector clear of populated areas unless this will delay the aircraft in reaching a suitable airfield
  • Ask for flying time needed (useful for co-ordination with other services and agencies)
  • As a tower controller be ready to provide assistance for possible evacuation immediately after landing:
    • Keep the active runway clear of departures, arrivals and vehicles according local instructions;
    • Keep the safety strip clear of vehicles;
    • Consider the possibility of a blocked runway;
    • Plan ahead for any pending traffic, if necessary delay start up clearances;
    • Make arrangements for additional stairs to speed up the passenger disembarkation process as appropriate;
    • Make arrangements for towing equipment to tow the aircraft to a secure location as appropriate;
    • Arrange for placing the aircraft on a location away from buildings and other aircraft;

Receiving a Bomb Threat at an ATC Unit

If a call for a planted explosive device on board of an aircraft is received in the ATC unit, a calm response to the caller could help obtain additional information. This is especially true if the caller wishes to avoid injuries or deaths. If told that the airplane cannot land and be evacuated in time, the bomb threat caller may be willing to give more specific information on the bomb’s location, components, or methods of activation.

The following general guidelines should be considered in such cases:

  • Remain calm
  • Attempt to keep the caller on the line as long as possible. Ask him/her to repeat the message. Record every word spoken by the caller.
  • Record the flight number of the threatened aircraft, double check with the caller the flight number.
  • Ask for the exact location where bomb has been planted.
  • Get as much information as possible about the caller, e.g., vocal characteristic, race, gender, group affiliation, why the bomb was placed.
  • Try to capture clues from background noises, which might indicate caller's identification and location.

Immediately after the caller hangs up:

  • Determine the location of the flight and, if necessary, contact the appropriate ATC unit if the flight is under control of another unit
  • Inform the ATCO controlling the subject flight; relay practical information if any was obtained from the caller (i.e. location of the bomb, components, or methods of activation)
  • Report the threat according to local instructions (i.e. to your supervisor, the applicable law enforcement agency and the emergency response coordinator)
  • Remain available, as law enforcement personnel will want to interview you.

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NATS Flight Deck Procedures Video

There will be times when controllers will have to cope with unusual situations such as weather avoidance or aircraft emergencies. It is important for controllers to have knowledge of the flight deck procedures that will be used by aircrew in such situations. The following video describes the generic procedures followed by aircrew in certain unusual situations:

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