1. A-CDM Snow Module
Training Pack
October 2016
Version 1

2. Introduction
It has long been recognised that improvements should be made to the de-icing processes at Heathrow. However, during snow and ice conditions, the standard A-CDM mode of operation is not configured to deal with the additional de-icing and anti-icing activities. The A-CDM Snow Module is a system enhancement designed to deal with these conditions by adding facilities for planning, scheduling, and tracking the de-icing of departure flights. When airport de-icing operations are in force, the A-CDM airfield status is set to “snow” by ATC. A-CDM recognises the change to its de-icing mode and displays customised information screens. When conditions improve and de-icing operations are no longer needed, the airfield status in A-CDM is adjusted accordingly and the system automatically reverts to normal running.

3. Snow Mode: A-CDM Snow Module
The A-CDM Snow Module will be activated when airfield conditions indicate that large numbers of aircraft will need de-icing in order to depart safely.
Once activated, a number of changes will be evident and the extent of these will depend on the type of access you have. There will be three main account types:
Regular/External user
Can view all data input but is unable to make any changes
De-icing requester
Can select a flight and request de-icing of one or more sections of the aircraft
Amend or cancel a de-icing request
Rig scheduler
View de-icing requests and allocate one or more rigs to the aircraft
Assign rigs to non de-icing tasks (e.g. refilling, maintenance, etc.)
Amend or cancel a rig allocation

4. Changes to the A-CDM Display: all users
The enhanced A-CDM module will display the Airfield Status at the top right of the screen. Clicking on the word ‘SNOW’ will display the airfield conditions:
The Departures screen will change to display de-icing information:

5. Changes to the A-CDM Display: all users
The new screen items are:
De-icer filter – to filter by DSP in addition to the other filter options (airline, handling agent)
Stand/Pad – where de-icing is to take place
De-Icing Status – where the activity is in the lifecycle
RZT/CZT/EZT – de-icing milestone timestamps (Ready, Commencement, End). ‘E’ is Estimated, ‘A’ is actual

6. Changes to Flight Information: All Users
When selecting a flight to view additional details, a new section will be visible that repeats the information available on the departures screen:
The times will be populated according to the TOBT set by the AO/GH, and the rig allocation times provided by the de-icing service provider.
The status of the de-icing activity will follow the following cycle:
Requested – AO/GH has asked for the aircraft to be de-iced
Allocated – the DSP has assigned one or more rigs to the task
Started – de-icing has started
Completed – de-icing is finished

7. Changes to the A-CDM Display: De-icing Requestor Only
Within the flight information drop down menu, you will see the option “De-Icing Request”. Clicking this link will open a new tab called ‘De-Icing’ where you will be able to select a flight and request de-icing tasks.

8. Requesting De-icing
If not already filtered, select the required airline and/or terminal:
A list of the day’s flights will be displayed. Click on the icon under Add/Update for the flight you wish to have de-iced:

9. Requesting De-icing
The default areas to de-ice are preselected for you: tail, wing and fuselage. You can add or remove all items from each section using the or icons, or one item at a time using the  or  icons Click OK to confirm the de-icing request.

10. Requesting De-icing
Two new icons will be displayed against the flight record after you have clicked OK: delete and view Delete: upon confirmation, the de-icing request will be cancelled and removed. This is not possible if the rig has been allocated; speak to your DSP to cancel View: a read-only version of the request screen will be displayed. Should you wish to amend the areas of the aircraft that need to be de-iced, click on the Add/Update icon and make your changes before clicking OK to confirm the update. The Departures screen will show updated information next to the flight showing the status of the de-icing request and subsequent activity. TOBT should be maintained via normal channels and any changes should be confirmed with the de-icing service provider.

11. FAQ : General
Q: Where do the actual de-icing start and end times come from?
A: Actual start of de-icing is set by the DSP via the Rig Schedule tool. Actual end of de-icing can be updated by DSP or will be set on ASAT when ATC gives start approval.
Q: How will the new processes operate with regulated flights?
A: If there is a CTOT applied to a flight, this will be dealt with on a case-by-case basis and efforts will be made to have the regulation lifted
Q: How will the new processes accommodate taxiway clearing activities?
A: These activities will be co-ordinated by a Snow Cell team. Where possible, clearance will occur when there is little or no traffic expected on a particular taxiway. It is therefore imperative that TOBT and EEZT is accurately maintained.
Q: If TOBT is updated to include EDIT, who is responsible for monitoring it?
A: The AO/GH remains responsible for the TOBT

12. FAQ : AO/GH and Pilots
Q: If I forget to request de-icing, can my DSP allocate a rig anyway?
A: Yes. The DSP has the ability to request for you.
Q: The team sent to de-ice my aircraft could not complete the job and will have to come back. What should I do?
A: Pilot: contact the tower and advise that the job has been aborted
ATC: will acknowledge
DSP: update EEZT accordingly.
Q: What should I do if the aircraft turn is delayed and I have already requested de-icing?
A: Inform your DSP as soon as possible and advise them of the time you expect doors to be closed. They will need to review their schedule and confirm the earliest time they can start de-icing. Once you have this information, update your TOBT.
Q: The rig hasn’t turned up, what do I do?
A: Call the DSP and confirm arrival time.

13. Glossary 1/2 Term Description Airfield status
One of five status settings that reflect the operational status of the airfield:
REGULAR, HINDERED, DISRUPTED, EMERGENCY/ACCIDENT, SNOW
For the purposes of this guide is it assumed this is set to SNOW.
CTOT
Calculated Take Off Time (regulation applied to restrict take-off time)
CZT (E/A)
Estimated/Actual commencement of de-icing time
Actual is set by the DSP
De-icing conditions
A to J grading of de-icing conditions, where A = meh and J = OMG!!
DIT (E/A)
Estimated/Actual duration of de-icing
DSP
De-icing Service Provider
EZT (E/A)
Expected/Actual end of de-icing time
Actual is set when ATC give start approval
Met conditions
One of three settings that are used in HOT calculations:
LIGHT, MODERATE, SEVERE

14. Glossary 2/2 Term Description TOBT Target Off Blocks Time TSAT
Target Start Approval Time
An indication of ground delay is evident if TSAT > TOBT
RZT (E/A)
Estimated/Actual ready for de-icing time
Actual is set when the pilot calls ATC and confirms ready

15. System Alerts
A number of new alerts will be available when in snow mode:
CDM40 - Aircraft not ready for de-icing
This alert highlights any flights that have not recorded Actual Ready for De-icing Time (ARZT) by the Estimated Ready for De-icing Time (ERZT), plus a 5 minute tolerance
CDM41 – De-Icing not confirmed
This alert highlights any flights that have requested de-icing but, by a configurable time before TOBT, no rig has been allocated
CDM42 – Hold over time will be exceeded
This alert highlights any flights where hold over time (HOT) is not sufficient to meet TTOT
CDM43 – De-icing scheduled before aircraft is ready
This alert highlights any flights where the Estimated Commencement of De-icing (ECZT) is prior to TOBT e.g. de-icing scheduled and TOBT is subsequently delayed
CDM44 – De-icing not compliant with TSAT
This alert highlights any flight where a TSAT improvement means the TSAT is less than the Estimated End of De-icing (EEZT)