What is an Approach Control Service?
Where ATC is provided for controlled flights associated with arrival or departure.
What is an ATS?
Air traffic service is a generic term meaning variously a;
-Air Traffic Control Service
-Flight information Service
-Air Traffic Advisory Service
Define an Air Traffic Control Service?
A service provided for the purpose of preventing collisions between a/c, and on the manoeuvring area between a/c and obstructions; and expediting and maintaining an orderly flow of traffic. (EU 923/2012)
To whom do we provide an Air Traffic control service?
-To all IFR a/c in Class A, B, C, D and E airspace
-To all VFR a/c in Class B, C and D airspace
-To all SVFR a/c
-To all aerodrome traffic at controlled aerodromes
What is a Flight Information Service?
A service provided for the purpose of giving advice and information useful to the safe and efficient conduct of flight.
To whom do we provide a FIS?
to all aircraft which are likely to be affected by the information and which are:
– Provided with an ATC service, or
– Otherwise known to relevant Air Traffic Services units.
FIS does not relieve the pilot-in-command of an aircraft of any responsibilities and the pilot-incommand has to make the final decision regarding any suggested alteration of flight plan
What is an Air Traffic Advisory Service?
-A service provided within advisory airspace to ensure separation, in so far as practicable, between aircraft operating on IFR flight plans.
What is advisory airspace?
An airspace of defined dimensions, or designated route, within which air traffic advisory service is available.
What is an advisory route?
A designated route along which air traffic advisory service is available.
Do controllers providing an ATAS have to coordinate?
Yes, excatly like controllers providing an ATC service.
What do IFR aircraft need before entering advisory airspace?
What must an IFR flight do if crossing an advisory route?
Must cross at an angle that is 90° to the direction of the route.
What are the RADAR separations that a controller must use?
5nm when using RADAR or surveillance equipment such as ADS-B
This can be reduced to 3nm provided the capabilites of the surveillance system allow.
What is an STCA?
Short Term Conflict Alert (STCA)
– visual and (sometimes) aural warnings if potential aircraft conflicts detected. (usually up to 2 minutes ahead).
What is RIMCAS?
Runway Incursion Monitor and Collision Avoidance System (RIMCAS)
• Fitted to some surface movement surveillance systems
• Provides Tower controllers with audio and visual warnings of potential conflictions on runways
• (PSR and SSR returns can both trigger RIMCAS) )
What is MTCD?
Medium Term Conflict Detection
A safety net that warns (visually and with an audio alarm) the controller of potential conflicts up to 20 minutes in advance.
Define identification with regards to PSR
The situation which exists when the position indication of a particular aircraft is seen on a situation display and is positively identified. (ICAO)
Describe the turn method of identification
• Ascertain the aircraft’s heading
• Observe the aircraft’s track for a period of time
• Correlate the observed movement of a particular Position Indication with;
1) The acknowledged execution of an instruction to alter heading by at least 30 degrees.
2) One or more changes of heading of at least 30 degrees, as instructed by another controller, or
3) One or more changes of heading of at least 30 degrees, reported by the pilot.
A turn for identification does not constitute the provision of a surveillance service
Before instructing an aircraft to turn, consider:
• PSR coverage
• Other surveillance returns
• Rules of the Air
• Proximity of Controlled airspace boundary
Caution must be exercised to ensure that;
-the movements of not more than one Position Indication match those of the aircraft
-This method is not used in areas where aircraft reguarly make turns for navigational purposes
Describe the departing aircraft method of identification
Identification is achieved by observing and correlating the Position Indication of a departing aircraft to a known airborne time. Identification is to be achieved within 1nm of the end of the runway used.
Take care to avoid confusion with:
• Aircraft overflying the airfield
• Aircraft making a Missed Approach
• Aircraft departing from an adjacent runway
• Aircraft holding overhead the airfield
Describe the position report method
By correlating a particular radar position indication with an aircraft reporting its position over, or as bearing and distance from,
• a point shown on the situation display, either
1) An exact reporting point, or
2) Over a notified visual reference point or prominent geographical feature, in either case approved for the purpose and displayed on the situation display. Must not be more than 3,000ft above this point to use it in the UK.
• and by ascertaining that the track of the particular radar position is consistent with the aircraft path or reported heading;
Both must be within PSR coverage to be valid points to use.
Use an alternative method if there is any doubt concerning the identification. The appropriate ATS authority may prescribe conditions for the application of these methods, e.g.:
i) a level or levels above which this method may not be applied in respect of specified navigation aids; or
ii) a distance from the radar site beyond which this method may not be applied.
Define an ERP
Exact reporting point.
A position established by a navigational facility, which is:
• Overhead a VOR or NDB
• A notified fix defined by VOR radials or a VOR radial and a bearing from an NDB
• A position defined by a VOR radial and a range from a co-located DME
What must a controller do if he loses identity of an a/c?
Inform that a/c of the loss of identification.
When is it necessary to inform a pilot that his a/c has been identified?
When the a/c has been identified outside Controlled Airspace. It is no longer required to pass a position report in this situation unless controller deems it necessary.
What are the methods for identifying an a/c using SSR?
• Observing compliance with the instruction to set a discrete four digit code.
• Recognising a validated four digit code Code/callsign conversion procedures may also be used if code/callsign pairing confirmed
• Observing an IDENT feature when it has been requested
(1) Possible mis-ident due to simultaneous requests to ident.
(2) Ident cannot be used for aircraft displaying a conspicuity code.
What methods are there to validate an assigned Mode A Code?
• Instruct aircraft to squawk assigned code and observe that the correct numbers appear.
• Instructing the aircraft to “squawk ident” and simultaneously checking that the code numbers are associated with the radar return.
• Matching a previously identified primary radar return with the assigned code for the flight.
Can be done at the same time as identifying.
When may a Mode A code be deemed validated?
When the code set can be recognised by the Code Assignment Plan to have been assigned by an ATC unit capable of validating the code, providing the code has not been notified as being corrupt.
What is verification?
A check to confirm that the aircrafts Mode C read out is accurate within agreed parameters. There are strict guidelines concerning the use of Mode C data which vary according to whether the readout is verified or not
• Mode C can be assumed to have been verified if associated with a deemed validated Mode A
• Verification may be achieved, if necesssary, with the assistance of another ATSU.
• If in error:- Request the pilot to “check altimeter setting and confirm level” If still in error: “Stop Squawk Altitude. Wrong indication” “Squawk 0000” – to indicate a data error (independent switching off of Mode A & Mode C not available)
How are levels assessed using mode C read Outs?
By checking that the level assessments correlate with the reported level of the aircraft, either by;
1. Maintaining an assigned level (level occupied) Mode C readout indicates +/-200ft from that level in RVSM (FL290-410) or +/- 300ft in other airspace, unless the ATS authority specify smaller (not less than +/-200ft). +/-200ft in the UK and on the sims in all airspace.
2. VACATED a level; when instructed to climb or descend Mode C readout shows a change of more than 300ft (400ft in UK) from the level, and is continuing in the anticipated direction.
3. PASSING through a level in the climb or descent Mode C readout shows the level has been passed by more than 300ft and is continuing in the required direction. 400ft in the UK
4. REACHED an assigned level Three successive Mode C readouts or 15 secs (whichever the greater) indicate the appropriate tolerance as in 1.
When should a pilot be informed of his a/c's position?
1. Upon identification, except when the identification is established:
i) based on the pilot’s report of the aircraft position; or within 1nm of the runway upon departure (and the observed position on the situation display is consistent with the aircraft’s time of departure;) or
ii) by use of either ADS-B / SSR Mode S aircraft ident or assigned discrete SSR codes and the location of the position indication is consistent with the CPL of the aircraft; Or
iii) by transfer of identification;
2. when the pilot requests this information;
3. when a pilot’s estimate differs significantly from the controller’s estimate based on the observed position;
4. when the pilot is instructed to resume own navigation after vectoring if the current instructions had diverted the aircraft from a previously assigned route;
5. immediately before termination of ATS surveillance service, if the aircraft is observed to deviate from its intended route.
In what ways can you pass position information to a pilot?
a)as a well-known geographical position;
b)magnetic track and distance to a significant point, an enroute navigation aid, or an approach aid;
c)direction (using points of the compass) and distance from a known position;
d)distance to touchdown, if the aircraft is on final approach; or
e)distance and direction from the centre line of an ATS route.