ASSIST is a simple set of acronyms which may make it easier for controllers to remember the immediate actions, or sequence of actions, to be followed on initial notification in the event of an unusual/emergency situation:
Many organizations successfully adopted the ASSIST principle pioneered by the Deutsche Flugsicherung GmbH (DFS) entrusted with controlling the air traffic in Germany
Pay attention during emergencies, the controller shall maintain necessary communication with the flight crew if possible and of course, in function of the situation. The air traffic controller shall avoid frequency change if he can continue to manage the traffic even outside of his responsibility area. Radar contact shall be maintained during the emergency activation period.
Situation:
- Poor braking can be due to contamination of the runway or due to technical problems
- Pilots can request the longest runway
The controller shall anticipate the following consequences:
The actions for the controller shall be:
| A | Acknowledge the emergency; inform the flight crew if fire/smoke is observed (not applicable for IVAO) |
| S | Acknowledge the emergency; inform the flight crew if fire/smoke is observed (not applicable for IVAO) |
| S | Silence the non-urgent calls (as required); use a separate frequency if possible (not applicable for IVAO) |
| I | Inform the airport emergency fire rescue services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight by providing any information requested and necessary such as type of approach, runway length and aerodrome details |
| T | Provide time for the flight crew to assess the situation; do not press them with non-urgent matters. |
Birds, which are flying around airfield, are dangerous for aircraft and can be the cause of many situations:
- Bird impact can break the windshield or canopy, creating loss of visibility from the flight deck or windshield penetration
- Birds may get into a jet engine and cause single or multi engine failure
- Aircraft hydraulics may get damaged and may bring about loss of control
According to real studies on bird strike incidents, in 40% the impact was on the aircraft engines. Another large portion of impacts are spread out over the aircraft nose, radome and flight deck windscreen.
The controller shall anticipate the following consequences during take-off:
The actions for the controller shall be:
| A | Acknowledge the bird strike, ask for the crew's intentions when the situation permits, minimize frequency changes, and establish whether the crew is able to control the aircraft |
| S | Separate the aircraft from other traffic, prioritize it for landing and keep the active runway clear of departures & arrivals |
| S | Silence the non-urgent calls (as required) and use a separate frequency if possible (not applicable for IVAO) |
| I | Inform the airport emergency services and inform the adjacent ATC units |
| S | Support the flight experiencing the consequences of the bird strike with any information requested and deemed necessary (e.g. type of approach, runway length and aerodrome details, etc.) |
| T | Provide time for the crew to assess the situation; do not press them with non-urgent matters. |
Situation:
- Aircraft can abort take-off during rolling before V1
In the event of an engine malfunction, flight crew should be able to safely reject the take off if the decision to do so is made at a speed not greater than the correctly calculated decision speed (V1). After V1, a reject should only be considered if there is a strong reason to believe that the aircraft will not fly.
The controller shall anticipate the following consequences:
The actions for the controller shall be:
Situation:
- Fire is the first enemy on board. Engines when facing failure can create fire
- A bird strike can create fire inside the engines
- When fire is detected, aircraft shall land as soon as possible on a suitable aerodrome
Fire in the air is one of the most hazardous situations that a flight crew can be faced with. A fire can lead to the catastrophic loss of that aircraft within a very short period of time.
The controller shall anticipate the following consequences:
The actions for the controller shall be:
The controller shall inform all pilots about:
In addition, the action for the controller shall be for private pilots:
| A | Acknowledge and ensure that the fire emergency is well-understood |
| S | Establish and maintain separation from other traffic and terrain |
| S | Impose silence on your control frequency, if necessary; and do not delay or disturb urgent cockpit action by unnecessary transmissions |
| I | Inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Provide maximum support to the flight crew |
| T | Allow the flight crew sufficient time to manage the emergency |
There are several possible situations:
- Gear cannot be extended or gear is partially extended
- Gear is extended but gear indication on cockpit panel is wrong
- No retraction of the gear is possible after take-off
- Gear collapse with subsequent airframe damage
Commercial airliners use complex retractable landing gears. The inboard system provides light indication regarding the status of the landing gear: a green light when the landing gear is down and locked and a red light when there is a discrepancy between the gear lever and landing gear positions. The unsafe indication might be the first sign of a problem related to the proper preparation of the landing gear for landing.
The controller shall anticipate the following consequences:
The actions for the controller shall be:
| A | Acknowledge the gear problem, ask for the crew's intentions when the situation permits, and establish whether the crew is able to extend the gear into locked position |
| S | Separate the aircraft from other traffic, prioritize it for landing and keep the active runway clear of departures & arrivals |
| S | Separate the aircraft from other traffic, prioritize it for landing and keep the active runway clear of departures & arrivals |
| I | Inform the airport emergency services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight experiencing gear problems with any information requested and deemed necessary |
| T | Provide time for the crew to assess the situation. Do not press them with non-urgent matters |
Situation:
- Smoke or fire in the cockpit is one of the most important dangers for the flight crew.
Fire in the air is one of the most hazardous situations that a flight crew can be faced with. A fire can lead to the catastrophic loss of that aircraft within a very short period of time.
The controller shall anticipate the following consequences:
The actions for the controller shall be:
The controller shall inform the pilot about:
| A | Acknowledge the emergency, inform the crew if fire/smoke is observed from the undercarriage area |
| S | Separate the aircraft and if necessary prioritize it for landing, allow long final if requested, keep the active runway clear of departures, arrivals |
| S | Silence the non-urgent calls (as required) and use a separate frequency if possible (not applicable for IVAO) |
| I | Inform the airport emergency services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight by providing any information requested and necessary such as type of approach, runway length and aerodrome details, etc. |
| T | Provide time for the crew to assess the situation. Do not press them with non-urgent matters |
Situation:
- Electrical problems are some of the random failures in an aircraft.
The consequence can be minor or major depending on the nature of failure and the number of instruments and/or systems out of order.- A complete black out can occur through loss of all generators before switching the battery
- Partial loss of some instrument sor systems (loss of communication, loss of navigation instruments or systems (FMC), loss of flight instruments or a combination of many factors).
The controller shall anticipate the following consequences:
The actions for the controller shall be:
The controller shall inform the pilot about:
| A | Acknowledge the emergency and provide position information and suitable vectors if navigational problems are reported |
| S | Separate the aircraft as necessary, expect the aircraft to request level change in order to maintain VMC |
| S | Silence the non-urgent calls (as required) and use a separate frequency if possible |
| I | Inform the airport emergency services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight by providing any information requested and necessary such as type of approach, runway length and aerodrome details, etc |
| T | Provide time for the crew to assess the situation. Do not press them with non-urgent matters |
Situation:
- Hydraulic problems are some of the random failures in an aircraft.
The consequence can be minor or major depending on the failure and the number of instrument and/or system out of order- The situation could be dramatic with complete or partial failure of flight controls
- Gear can be locked in extension or cannot be unlocked from docking position
- Braking efficiency can be impacted
- Flaps can be blocked in position (extended or not, in function of the flight)
- Nose wheel steering may not work
The controller shall anticipate the following consequences:
The actions for the controller shall be:
The controller shall inform the pilot about:
| A | Acknowledge the hydraulics problem. Ask for the crew's intentions when the situation permits, and establish whether the crew is able to control the aircraft |
| S | Separate the aircraft and if necessary prioritize 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 a separate frequency if possible (not applicable for IVAO) |
| I | Inform the airport emergency services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight by providing any information requested and necessary such as type of approach, runway length and aerodrome details, etc. |
| T | Provide time for the crew to assess the situation. Do not press them with non-urgent matters |
Situation:
- Engine failure can occur during take-off or when flying
- A bird strike can provoke engine failure
- Engine failure can imply an engine shutdown
- Engine failure cannot be a complete engine shutdown
- Engine on fire
The controller shall anticipate the following consequences:
The actions for the controller shall be:
The controller shall inform all pilots about:
| A | Acknowledge the problem. Ask for the flight crew's intentions when the situation permits |
| S | Separate the aircraft from other traffic and allow room to manoeuvre |
| S | Silence the non-urgent calls (as required) and use a separate frequency if possible (not applicable for IVAO) |
| I | Inform the airport emergency services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight by providing any information requested and necessary such as type of approach, runway length and aerodrome details, etc. |
| T | Provide time for the crew to assess the situation. Do not press them with non-urgent matters |
Situation:
- Low oil pressure can be a consequence of engine failure (single or multi).
- Low oil pressure can be a consequence of outside landing
The controller shall anticipate the following consequences:
The action for the controller shall be:
| A | Acknowledge the problem. Ask for the flight crew's intentions when the situation permits |
| S | Separate the aircraft from other traffic and allow room to manoeuvre |
| S | Silence the non-urgent calls (as required) and use a separate frequency if possible (not applicable for IVAO) |
| I | Inform the airport emergency services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight by providing any information requested and necessary such as type of approach, runway length and aerodrome details, etc. |
| T | Provide time for the crew to assess the situation. Do not press them with non-urgent matters |
Fuel problems can be caused by the following situations:
- One engine failure
- Multi engine failure
- Outside landing
- Permanent gear extension
- Fuel circuit failure (fuel leakage)
- Too long holding (more than 30min)
The controller shall anticipate the following consequences:
The actions for the controller shall be:
The controller shall inform all pilots about:
| A | Acknowledge the problem. Ask for the flight crew's intentions when the situation permits |
| S | Separate the aircraft from other traffic and allow room to manoeuvre |
| S | Silence the non-urgent calls (as required) and use a separate frequency if possible (not applicable for IVAO) |
| I | Inform the airport emergency services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight by providing any information requested and necessary such as type of approach, runway length and aerodrome details, etc. |
| T | Provide time for the crew to assess the situation. Do not press them with non-urgent matters |
Situation:
- Fuel dumping is necessary when the current mass of the aircraft is greater than the maximum landing weight
The controller shall anticipate the following consequences:
The actions for the controller shall be:
The controller should inform all pilots about:
| A | Acknowledge the problem. Ask for the flight crew's intentions when the situation permits |
| S | Separate the aircraft from other traffic and allow room to manoeuvre |
| S | Silence the non-urgent calls (as required) and use a separate frequency if possible (not applicable for IVAO) |
| I | Inform the airport emergency services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight by providing any information requested and necessary such as type of approach, runway length and aerodrome details, etc. |
| T | Provide time for the crew to assess the situation. Do not press them with non-urgent matters |
Situation:
- When crossing a cloud at specific conditions (temperature), icing may occur on the aircraft (wings, propeller).
Controllers should stay alert for any extraordinary climb/descent. They should be ready to provide climb/descent to affected traffic and allow space for horizontal manoeuvres. The aircraft, experiencing severe icing would certainly need increased separation as its flying characteristics will be degraded.
The controller shall anticipate the following consequences:
The actions for the controller shall be:
The controller should inform all pilots about:
| A | Acknowledge the problem. Ask for the flight crew's intentions when the situation permits |
| S | Separate the aircraft from other traffic and allow room to manoeuvre |
| S | Silence the non-urgent calls (as required) and use a separate frequency if possible (not applicable for IVAO) |
| I | Inform the airport emergency services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight by providing any information requested and necessary such as type of approach, runway length and aerodrome details, etc. |
| T | Provide time for the crew to assess the situation. Do not press them with non-urgent matters |
Many of the previous emergency situations can occur inside the airspace of an area control centre. In addition, there are a few more situations which can occur mainly on area control centre airspace.
Situation:
- Inside or under some clouds, there are lightning strikes
The controller shall anticipate the following consequences:
The actions for the controller shall be:
The controller shall inform all pilots about:
| A | Acknowledge the problem. Ask for the flight crew's intentions when the situation permits |
| S | Separate the aircraft from other traffic and allow room to manoeuvre |
| S | Silence the non-urgent calls (as required) and use a separate frequency if possible (not applicable for IVAO) |
| I | Inform the airport emergency services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight by providing any information requested and necessary such as type of approach, runway length and aerodrome details, etc. |
| T | Provide time for the crew to assess the situation. Do not press them with non-urgent matters |
Situation:
- Pressurisation problems can occur at any time
- In-flight fire is one reason to make an emergency descent to an alternate airfield
- When a major problem occurs in the aircraft, an emergency descent shall be performed by the flight crew
An emergency descent may be initiated without prior warning. Depending on the circumstances, the flight crew may start a high vertical speed descent without warning if the safety of the aircraft is at risk.
Decompression is defined as the inability of the aircraft's pressurisation system to maintain its designed pressure schedule.Decompression can be caused by a malfunction of the system itself or by structural damage to the aircraft.
The controller shall anticipate the following consequences:
The actions for the controller shall be:
The controller shall inform all pilots about:
| A | Acknowledge the problem. Ask for the flight crew's intentions when the situation permits |
| S | Separate the aircraft from other traffic and allow room to manoeuvre |
| S | Silence the non-urgent calls (as required) and use a separate frequency if possible (not applicable for IVAO) |
| I | Inform the airport emergency services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight by providing any information requested and necessary such as type of approach, runway length and aerodrome details, etc. |
| T | Provide time for the crew to assess the situation. Do not press them with non-urgent matters |
Based on the information provided by the flight attendants, an on-board medical professional, the captain in command will make the decision to either continue the flight to the planned destination or to divert to a closer or otherwise more suitable aerodrome. The pilot should desire ATS priority, declaration of an emergency.
Situation:
- Passenger syncope
- Passenger heart attack
- Passenger nausea/vomiting
- Pregnant lady gives birth
The controller shall anticipate the following consequences:
The actions for the controller shall be:
The controller shall inform all pilots about:
| A | Acknowledge the problem. Ask for the flight crew's intentions when the situation permits |
| S | Separate the aircraft from other traffic and allow room to manoeuvre |
| S | Silence the non-urgent calls (as required) and use a separate frequency if possible (not applicable for IVAO) |
| I | Inform the airport emergency services and inform the adjacent ATC units if the aircraft is approaching or is near to their areas of responsibility |
| S | Support the flight by providing any information requested and necessary such as type of approach, runway length and aerodrome details, etc. |
| T | Provide time for the crew to assess the situation. Do not press them with non-urgent matters |