ADS and Datalink Flashcards
What ADS contracts are available?
- periodic
- event
- on-demand
What action shall a controller take on receipt of a DISCONNECT REQUEST with a reason code 1 ‘congestion’?
The current controlling authority should be notified. The controlling authority should resolve the situation.
What will happen if a controller attempts to connect ADS with an aircraft when all the aircraft ADS connections have been taken by other ground facilities?
DISCONNECT MESSAGE with reason code 1 ‘congestion’ is received.
When shall controllers terminate ADS contracts and connections?
Automatically terminated by OCS at a VSP past the FIR boundary. If re-establishing manually past this point, the controller must manually terminate the connection.
When may a controller consider increasing ADS reporting rates?
- an aircraft is approaching a crossing route on which there is other traffic
- when the aircraft is approaching areas of known significant weather
- during periods of turbulence
- when an unauthorized deviation from the clearance is detected
- when the aircraft is experiencing abnormal operations or it is known or suspected that an aircraft is in a state of emergency
What vertical tolerance is applied to ADS?
plus or minus 200ft
When is a CPLDC message closed?
When either:
- a response is not required, or
- a referenced response other than “STANDBY” or “REQUEST DEFERRED” has been received
When must pilots downlink a CPDLC position report?
On completion of:
- an initial CPDLC connection (e.g. inbound from domestic)
- a CPDLC connection transfer
- when crossing an FIR boundary
When should freetext messages be used?
Only when an appropriate pre-formatted message element does not exist
If a CPDLC dialogue is interrupted by a system shutdown, what process should be followed?
The entire dialogue shall be recommenced by voice communications.
What are appropriate responses to a negotiation request?
AFFIRM
NEGATIVE
When should a pilot or controller consider re-sending a message?
After a reasonable period of time has passed and no error message has been received indicating non-delivery of the message. The message shall be sent as a query message.
How far may a pilot deviate of track due to wake turbulence, without a clearance from the controller?
2NM
How may a controller cancel a block altitude clearance?
CANCEL BLOCK CLEARANCE followed by:
- MAINTAIN
- CLIMB TO AND MAINTAIN
- DESCEND TO AND MAINTAIN
How should a controller respond when a multi-element clearance request is received and only part of it can be approved?
Uplink shall not contain single word UNABLE and a clearance. If UNABLE is used in a clearance message it must contain a qualifier to remove any ambiguity.
How does a controller acknowledge a CPDLC emergency message?
Freetext using the words ROGER MAYDAY or ROGER PAN.
What letters and numbers are used when an AOC wishes to indicate that an aircraft is CPDLC capable?
J1 to J7.
What field of the flight plan is used to identify an aircraft’s datalink capabilities?
Field 10a.
What letter and number is used when an AOC wishes to indicate that an aircraft is ADS-C FANS 1/A capable?
D1 or G1.
When should the MONITOR (or CONATCT) and END SERVICE messages normally be sent?
MONITOR send automatically by OCS
END SERVICE sent automatically 3 minutes prior to FIR boundary
What actions should the controller carry out on becoming aware that the END SERVICE message has not been delivered?
Send another END SERVICE message. If unsuccessful the pilot shall be instructed to terminate the CPDLC connection and log on to the next unit.
How may an AFN logon be initiated?
- manually by the pilot during initial logon
- by the OCS using address forwarding process
What is the purpose of an AFN logon?
Provide the ATSU with the datalink application ‘context’ of the aircraft
- the ATS datalink applications supported by the aircraft and the version numbers of these applications
- the unique ACARS address of the aircraft
- provide the ATSU with the aircraft ID, aircraft registration and aircraft address. This allows comparison between logon information and the flight plan
When should a pilot perform the initial logon?
- prior to takeoff, not more than 45 minutes prior to ETD to the current ATSU the departure airport is located within
- above 10,000ft
- following an unsuccessful datalink transfer to another ATSU when detected by pilot or on instruction from ATC
What is the purpose of a CPDLC connection?
Allow the exchange of CPDLC messages between an aircraft and an ATSU.
MATSOS states that controllers shall manage CPDLC connections to support a requirement. What is this requirement?
To ensure that the ATSU with control of the flight holds the active CPDLC connection.
What happens if there is an existing CPDLC connection with an aircraft and a connection request is sent by an ATSU?
- the system verifies that the ATSU sending the CR1 has been specified as the next data authority. If so, the aircraft system:
- accepts the CR1
- establishes the connection as the inactive connection
- responds with a CC1
- otherwise rejects the CR1 by sending a DR1 message that contains the identity of the current data authority
What happens if there is no existing CPDLC connection with an aircraft, and a connection request is sent by an ATSU?
The aircraft system:
- accept this CR1
- established this CPDLC connection as the active connection
- responds with a CPDLC connection confirm (CC1)
Describe the datalink connections that an aircraft may have at any time with ATS units.
- an active and an inactive CPDLC connection
- up to 5 ADS connections
Describe what happens if you sent a CPDLC message to an aircraft when you have an inactive CPDLC connection.
The aircraft system rejects the connection and sends DM63 NOT CURRENT DATA AUTHORITY
Why must a Next Data Authority message be sent as the first step in the CPDLC transfer sequence?
To avoid rejection of the connection request.
What is the purpose of the Next Data Authority message?
To allow the controlling ATSU to notify the aircraft of the identity of the next ATSU authorised to establish an inactive CPDLC connection.
Explain the process of the normal life sequence of a CPDLC connection.
??DLM 6??
What will happen if a duplicate Next Data Authority message is sent to an aircraft?
Some aircraft types may terminate an Inactive CPDLC connection even if the facility designator in the NDA message is the same.
What is the purpose of Address Forwarding?
To allow a subsequent ATSU to establish an inactive CPDLC connection and ADS-C contracts, and to allow adjacent ATSUs to establish ADS-C contracts for monitoring purposes.
Under normal conditions, how does the avionics respond to an END SERVICE message?
The aircraft will downlink a CPDLC DISCONNECT REQUEST message. The aircraft will consider the aircraft to be disconnected as soon as the DR1 message has been sent.
