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 | Free the longest runway available. Expect long landing or overrun. Propose to divert if runway length is not enough for Pilot in Command. Do not make short sequence behind this aircraft. |
| 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, flying around airfields, 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 (= radar dome) 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 |
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 |