CPDLC / ADS

Introduction

Agenda

Here are the topics for this module.

1. CPDLC / ADS Introduction1. CPDLC / ADS Introduction

2. CPDLC2. CPDLC

3. CPDLC Operations Fundamentals3. CPDLC Operations Fundamentals

4. ADS C 4. ADS C

5. Contingencies

DefinitionsCNS / ATM – Communications Navigation & Surveillance / Air Traffic ManagementCPDLC – Controller Pilot Data Link Communications

Augments verbal ATC instructions and pilots read-backs & automates ATC processes

ADS C – Automatic Dependent Surveillance ContractGives accurate position reportingAllows additional data reporting (wind, temperature etc)Provides reporting in regions out of radar coverageIncreases traffic that can be handled in remote areas

AFN – ATS Facilities NotificationAllows logon to ATC facility (Data Authority) & the transfer of control

PBN – Performance Based Navigation

These are some of the acronyms related to CPDLC and ADS. We will start off with a look at how CPDLC and ADS fit into the “big picture”.

Going Systemic

CPDLC and ADS are pieces of ICAO’s bigger plan to take over the world.

ICAO Headquarters

I think we’re on to something here boys. We’re going systemic and control the world.

CNS ATM

How they fit

The "C", the "N", and the "S" from the CNS equation stand for "Communication, Navigation, and Surveillance". There are several components that fit into each of these categories, This module covers CPDLC and ADS.

PBN

ADSCPDLC

CNSCommunication

Surveillance

Navigation

CPDLC vs. ADS

The CPDLC function supports: (a) Emergency alerting, (b) Uplink of ATC clearances and instruction, (c) Downlink of position reports and clearance requests, and (d) Free text as a supplement to preformatted elements.

The ADS function supports: (a) Emergency alerting, and (b) Automatic reporting by the aircraft’s Flight Management System (FMS) of aircraft position and intent information in accordance with parameters established in contracts by the ground system.

CPDLC and ADS have different functions. CPDLC is used for general communications with ATC. ADS C is primarily used for automatic position reporting. We will first look at CPDLC.

CPDLC Introduction

CPDLC is a powerful tool to sustain data link communications between a pilot and the controller of the relevant flight region. It is particularly adapted to such areas where voice communications are difficult (e.g. HF voice over oceans or remote part of the world), and is expected to become very convenient to alleviate congested VHF of some busy TMAs when utilized for routine dialogue (e.g. frequency transfer).

CPDLC Communications

CPDLC consists in the exchange of messages, which can be formed by the use of individual (or combination) elements chosen within a set of internationally agreed preformatted ATC words. You also have a free texting capability.

When Can We Expect?Do to

Perform

ance

Due to Weather

Maintain Own Separation

At Pilot DiscRe

ques

t Crz

Clb

Mayday M

ayday

Data Link Overview

CPDLC uses data link. Data link is a general term for digital data transfer between the airplane and various ground stations. Different data link names are based on where given information is sent to or received from.

N767A

Types of Data Link:

ATC Data link

Exchange requests & text messages

Clearances, reporting points,

climbs/descents requests etc.

ADS periodic and event reporting

Company Data link

Airline Operation Communication or

AOC data link (Universal Weather)

ACMS Data link

Maintenance

ACARS Overview

ACARS is a system on the airplane to transmit and receive the data link information. ACARS communicates incoming and outgoing data and messages through the center VHF radio or SATCOM system. The information can be automatically or manually controlled.

ACARS Company Data link example

More information about ACARS and the Data link types are found in the FCOM: Sections 5.20, 5.40, 11.33 and 11.34.

Universal Weather

Data link Access

You use the Computer Display Unit for both ATC and company data link. The menu and FMC COMM switches allow you to access the company data links.

ATC Key

Pushing the ATC key displays one of four pages.

Holding the ATC key down displays the Emergency Report page.

Logon/Status page if a CPDLC connection has not been established with an ATC Center.

ATC Uplink page if there is a new uplink message to be reviewed.

Log page if there are more than one new uplink message or more than one open uplink message.

ATC Index

Note the pages that come up when selecting the ATC key can also be accessed through the ATC index page, except for ATC uplink.

Emergency Report

The emergency report page alerts ATC of an emergency onboard the aircraft. Sending this report automatically places Automatic Dependent Surveillance (ADS) into the emergency mode if MAYDAY was selected.

ATC Request

ATC request allows the entry of altitude, speed, and offset direction and distance requests.

ATC Report

The ATC Report page lists required reports requested by ATC.

Clearances that Require a Report

Some ATC uplinks request a report. When you accept the clearance, an ATC report is automatically generated.

Automatic Reporting

Some requests, such as report reaching, report level and report passing can be armed to automatically send the report. An ARM prompt appears when you accept the request. Selecting ARM automatically sends the report when the condition is met.

ATC Log

The ATC log displays the beginning of stored uplink and downlink messages, with the most recent on the top. The Log erases automatically after flight completion.

Once you look at a message, the status changes to either OLD or OPEN depending on whether a response is required or not.

This message required a response and ACCEPTED was sent.

Make sure there are no messages left OPEN

Logon / Status pages

You use the logon/status pages to initially logon and verify station connection.

Initiates data link connection with the desired ATC facility.

Allows the emergency on/off and arming capability for ADS.

The Logon/status has 2 pages

Position Report

The position report key takes you to the position report page of the FMC. Notice that when Datalink is connected to a station, you can also send a position report to ATC.

When Can We Expect

The When can we expect page allows you access to standardized requests.

Free Text

You use the Free Text Page to create and send a free text message to the controller.

Clearance

The clearance page notifies ATC of readiness to accept a clearance, such as a pre-departure or pushback clearance.

Note: This function is not currently being used.

Voice

The voice page notifies ATC that you request voice contact from the controller.

Long Term Data Link Com Failure

If you lose the connection and it has not been restored after a continuous period of 16 minutes, the message ATC COMM TERMINATED will be displayed and the link with ATC will be lost. The FMC data link status will show NO COMM during this time.

Revert to voice communications and notify ATC of the situation.

CPDLC Operations FundamentalsHandling of CPDLC messages requires time:

Reading and interpreting a written clearance was found to be less immediate than hearing the same onePreparing and sending a request through the CDU is longer than directly using the mike

The party line is lost (the pilot can no longer listen to the surrounding transmissions)

Communicating via data link brings new challenges.

radio datalink

Crew Resource Management Considerations

When data link messages replace normal voice communications, it is important that both pilots silently and independently read any uplink message.Pilots should then discuss and evaluate the message for appropriate action.Likewise, any downlink message should first be selected and assembled and then verified by both pilots before sending to ATC.

Like all other tasks, data link operations require CRM skills.

Looks good You OK with it

Communication Philosophy

Voice and data link are complementary modes of communication.

Select the most appropriate mode for each situation.

Data link is designed for routine messages including ATC clearances, position

reports, and flight plans.

In non-routine circumstances, or when safety or complexity are factors, voice

(SATCOM, HF, or VHF) may be the preferred mode of communication.

Flight crew responsibilities are identical using either voice or data link.

The pilot communicating is responsible for all communication related duties.

CPDLC communication is not intended to be as fast a means of (tactical) communication as voice. It is designed to pass routine (strategic) messages, where time is not an essential factor.

Communicating with ATCHF voice capability still remains a requirement and must be monitored even when CPDLC is being used for position reports and clearances. Operators must comply with the voice communications procedures associated with CPDLC.

Communications initiated with ATS by voice should be completed by voice and communications initiated by CPDLC should be completed, whenever possible, by CPDLC.

Voice contact is not replaced by data link. Data link augments voice and should be used when available, but voice contact should always be an option.

ADS Contract = Reporting

Position ReportingEmergency Reporting

ADS provides surveillance capability in oceanic and en-route continental airspace. It replaces verbal position reporting in areas where non-radar separation is currently applied. ADS establishes contracts between ground systems and an airplane. An ADS contract is a reporting plan that establishes the requirements for ADS data reporting and the frequency of the reports.

Automatic Dependent Surveillance (ADS)

The ADS function defaults to the armed state on powering up the system. You only have limited interaction ability with ADS – C, the function can be manually turned on or off as can the ADS Emergency Mode.

ADS can send normal position reports and also signal an emergency condition.

Automatic Position Reporting

Page two of the ATC LOGON/STATUS displays active when ADS is connected to the ATS facility. Normally, position reports happen automatically when ADS is connected. If ADS is not connected you need to manually send position reports.

Manually Sending Position Report

Logged on Not logged on

If the ADS connection is not active, then you can manually send a position report to ATC whenever a Data link connection exists.

Required Manual Position Report

Even when ADS is connected, there are a few instances when you need to manually send ATC a position report.

Contingency Operations using CPDLC

Normally, during an emergency you immediately revert to voice communications. However, in certain situations, it may be more expeditious to first declare an emergency using the Emergency Report page. You use the Emergency Report page to generate the report, You use the Verify Emergency page to send it.

ADS Emergency

ADS-C active (non-radar environment) Radar Environment

You use the ADS EMERG function to indicate an emergency condition to ATC. This function is operationally equivalent to squawking 7700 when in radar coverage.

ADS Emergency Selection: 2 Ways

Manually Select ADS EMERG Automatically Selected from Emergency Report

If ADS EMERG is manually selected, then the only indication presented to controllers is that an emergency situation exists. Unlike an SSR squawk, there is no capability to differentiate between a Hijacking, a Radio Fail, or a Mayday. So there is a protocol to verify the intent.

ADS Emergency Mode

It’s hard to say how it happened, but the ADS is now in emergency mode.

What are you doing?

Hey, I think I’ve got this ATC datalink stuff figured out

CONFIRM SPEED CONFIRM ADS

If ATC receives an ADS emergency indication without any other CPDLC, SSR code, or voice confirmation of an emergency situation, they will immediately check for covert activation by either CPDLC or voice using the routine message CONFIRM SPEED and the words "CONFIRM ADS".

Could be trouble

Oops

On receipt of this CPDLC or voice message, check the status of the ADS Emergency Mode. If the mode has been selected to ON accidentally, then select the "ADS Emergency Off" prompt and notify ATC by either voice or CPDLC free text (as appropriate), of the new status by using the words "ADS RESET".

A-D-S Reset

ON & OFF toggles with each switch push

ADS EMERG is OFF ADS EMERG is ON

Houston We Have a Problem

If you deliberately and covertly selected the ADS Emergency Mode to ON, then reply to the CONFIRM SPEED uplink and leave the ADS Emergency Mode in the ON position.

ADS Emerg is ON

Uh oh!

Alert

If the aircraft continues with the ADS emergency mode activated ATC will assume that the aircraft is in emergency conditions and will follow normal alerting procedures.

Contingency Summary

You can find this information in the reference manual titled “Guidance Material for ATS Data Link Services in North Atlantic Airspace”.

What is the ADS Emergency function used for?

ADS emergency sends an emergency position report to ATC

ADS emergency is equivalent to squawking 7700 when in a non radar environment and ADS is active

ADS emergency sends Mayday Mayday to ATC

You use ADS emergency to signal an engine failure while in RVSM / MNPS

airspace

Select the best answer

It is not necessary to monitor the radios when CPDLC is active.

True

False

Select the correct answer

Which display indicates that ADS EMERG is ON?

Select the correct answer

Select the best statement regarding clearances received using CPDLC ?

CPDLC is expected to become very convenient to alleviate congested VHF of some busy TMAs because it is quicker for pilots to understand clearances

CPDLC allows quicker acceptances of clearances because only pilot is required to monitor CPDLC messages

CPDLC is superior to voice clearances because digital data moves very fast

Handling of CPDLC messages require time: Reading and interpreting a written clearance is less immediate than hearing the same one

Select the best answer

Module Complete

Can’t wait to figure out how the needs analysis impacted the human factors issue of CPDLC design and how this will affect the airspace… Or maybe I’ll just go workout.