/On the Aeriaa Airport Dashboard (part V) – Time milestones.

On the Aeriaa Airport Dashboard (part V) – Time milestones.

Before processing thousands of events, scenarios, etc. for feeding the Dashboard, I would like to show the a dimension that put in context almost every event. The time dimension. Delays are the “Oh, no, a delay again, what was the captain reason this time?” The late arrival of the plane, air regulation over the airport…I heard once that the guilty factor was the “shamefulness of being part of an airline because the ramp handling staff were late….some other details were given by the captain and it was a gesture of honesty”. We, the passengers only concern about only time milestone, the scheduled departure time of our flight, and pray for not have a big delay, but there are always 10, 15 minutes of courtesy. In this post, you will see dozens of time milestones, that impact over all the punctuality process of the flight operation and consequently will be marked in the Dashboard we are defining in this blog (this is the part V of this series).

Airport timetable

The next graphic shows the general process of a flight turnaround from the arrival to the departure.

Aircraft Turnaround process
Aircraft Turnaround Process

In the next time lapse video, you can see the a Lufthansa turnaround process, including the arrival flight en-route track, ATC conversations, and the destination’s enroute track. Great video of the AirportFreak Blog.

So, after the general turnaround process with the main flight related activities shown in the graphic and video, it’s time to speak about times.There are three main groups of time’s milestones. The scheduled times, the estimated times and the actual times, almost the time’s metrics are around them. Prepare to view them:

ACRONYMDEFINITIONEXPLANATION
ACGTActual Commence of Ground Handling TimeThe time when ground handling on an aircraft starts, can be equal to the Actual In-Block Time (AIBT) (to be determined locally)
ACZTActual Commencement of De-icing TimeThe time when de-icing operations on an aircraft starts.
AEZTActual End of De-icing TimeThe time when de-icing operations on an aircraft end.
AIBTActual In-Block TimeThe actual date and time when the parking brakes have been engaged at the parking position.
ALDTActual LanDing TimeThe actual date and time when the aircraft has landed (touch down)
AOBTActual Off-Block TimeThe actual date and time the aircraft has vacated the parking position (pushed back or on its own power).
AOSTActual On Stand TimeThe time at which the aircarft stops at the stand
ARDTActual ReaDy TimeThe time when the aircraft is ready for start up/push back or taxi immediately after clearance delivery, meeting the requirements set by the TOBT definition
AROTArrival runway occupancy timeThe time interval between the aircraft crossing the threshold and its tail vacating the runway.
ARZTActual Ready for De-icing TimeThe time when the aircraft is ready to be de-iced.
ASBTActual Start Boarding TimeThe time when passengers are entering the bridge or bus to the aircraft
ASRT
Actual Start Up Request Time
Time the pilot requests start up clearance
ATAActual Time of ArrivalThe time at which a craft arrives at a specified point at a destination.
ATDActual Time of DepartureThe time of leaving a specified point at a place. The actual time an aircraft becomes airborne.
ATOT
Actual Take Off Time
The time that an aircraft takes off from the runway. (Equivalent to ATC ATD–Actual Time of Departure, ACARS = OFF)
ATTT
Actual Turn-round Time
Metric AOBT – AIBT
AXIT
Actual Taxi-In Time
Metric AIBT – ALDT
AXOT
Actual Taxi-Out Time
Metric ATOT – AOBT
CETClearance Expiry TimeThe expired time when an air traffic control authorisation by ATC for an aircraft to proceed under specified conditions within controlled airspaces
CLDTCalculated LanDing TimeA flight’s frozen calculated landing time.
COBTCalculated Off-Block TimeCTOT (Calculated Take-Off Time) minus taxi time.
CTAControlled Time of ArrivalAn ATM imposed time constraint on a defined merging point associated to an arrival runway.
CTOControlled Time OverAn ATM imposed time constraint over a point.
CTOT
Calculated Take Off Time
A time calculated and issued by the appro- priate Central Management unit, as a result of tactical slot allocation, at which a flight is expected to become airborne. (ICAO Doc 7030/4 – EUR, Table 7)
DROTDeparture runway occupancy timeThe time interval between [the aircraft] crossing the stop bar at the holding point and the main gear lift-off from the runway.
EATExpected Approach TimeThe time at which ATC expects that an arriving aircraft, following a delay, will leave the holding fix to complete its approach for a landing.
ECZT
Estimated Commencement of De-icing Time
The estimated time when de-icing operations on an aircraft are expected to start
EDCTExpect Departure Clearance TimeThe time issued to a flight to indicate when it can expect to receive departure clearance. EDCTs are issued as part of Traffic Management Programs, such as a Ground Delay Program (GDP).
EDIT
Estimated De-icing Time
Metric EEZT – ECZT
EDTOExtended Diversion Time OperationsAn EDTO is a flight by a turbine powered aeroplane where the time at the one engine inoperative cruise speed (in the ISA and still air) from a point on route to an adequate aerodrome is greater than the following;
Twin engine aircraft certificated to carry more than 19 passengers or 3410 kilograms payload – 90 minutes
Aircraft with more than 2 engines – 180 minutes
Aircraft engaged in passenger carrying operations but not certificated to carry more than 19 passengers – 180 minutes.
EET
Estimated Elapsed Time
The estimated time required to proceed from one significant point to another (ICAO)
EEZT
Estimated End of De-icing Time
The estimated time when de-icing operations on an aircraft are expected to end
EIBT
Estimated In-Block Time
The estimated time that an aircraft will arrive in-blocks. (Equivalent to Airline/Handler ETA – Estimated Time of Arrival)
ELDT
Estimated Landing Time
The estimated time that an aircraft will touch- down on the runway. (Equivalent to ATC ETA –Estimated Time of Arrival = landing)
EOBT
Estimated Off-Block Time
The estimated time at which the aircraft will start movement associated with departure (ICAO)
EOSTEstimated On Stand TimeThe estimated time at which the aircarft will stop at the stand
ERDTEstimated ReaDy TimeThe estimated time when the aircraft is ready for start up/push back or taxi immediately after clearance delivery, meeting the requirements set by the TOBT definition
ERZT
Estimated Ready for De-icing Time
The estimated time when the aircraft is expected to be ready for de-icing operations
ETAEstimated Time of Arrival(ICAO) For IFR flights, the time at which it is estimated that the aircraft will arrive over that designated point, defined by reference to navigation aids, from which it is intended that an instrument approach procedure will be commenced, or, if no navigation aid is associated with the aerodrome, the time at which the aircraft will arrive over the aerodrome. For VFR flights, the time at which it is estimated that the aircraft will arrive over the aerodrome.
ETDEstimated Time of DepartureThe estimated time at which an aircraft will become airborne.
ETOEstimated Time Over significant pointEstimated entry time over an airspace for a non-regulated flight based on flight plan data and Environment Database (ENV) data.
ETOT
Estimated Take Off Time
The estimated take off time taking into account the EOBT plus EXOT.
ETTEstimated Time IntervalThe earliest/latest ETA at a waypoint, provided the aircraft flies the 4D Trajectory at its max/min allowable speed, wind/temp error is also taken into account, in order to guarantee that any CTA defined within associated ETA min/max interval will be satisfied with high probability.
ETTAEstimated Time Of Turn AroundThe time estimated by the AO/GH (aircraft operator/ground handler) on the day of operation to turn-round a flight taking into account the operational constraints.
ETTT
Estimated Turn-round Time
The time estimated by the AO/GH on the day of operation to turn-round a flight taking into ac- count the operational constraints
EXITEstimated Taxi-In TimeThe estimated taxi time between landing and in-block.
EXIT
Estimated Taxi-Out Time
The estimated taxi time between off-block and take off. This estimate includes any delay buffer time at the holding point or remote de-icing prior to take off
EXOTEstimated Taxi-Out TimeThe estimated time between off-block and take off. This estimate includes any delay buffer time at the holding point or remote de-icing prior to take off.
FRTTFlight crew reaction time to ATC take-off clearanceThe time interval between the ATC clearance for either line-up or take-off and commencement of taxiing to line-up.
IOBTInitial Off-Block TimeThe off-block time as given in the FPL and updated by flight plan associated messages (DLA, CHG, etc.).
LUPTLine-up timeThe time interval between crossing the stop bar and the moment the aircraft is fully lined up.
MTTT
Minimum Turn-round Time
The minimum turn-round time agreed with an AO/GH for a specified flight or aircraft type
ROTRunway occupancy timeThe amount of time that each aircraft occupies the runway.
RTARequired Time of ArrivalThe aircraft function to follow a CTA
SIBT
Scheduled In-Block Time
The time that an aircraft is scheduled to arrive at its first parking position
SLDTScheduled LanDing TimeThe scehduled date and time when the aircraft has landed (touch down)
SOBT
Scheduled Off-Block Time
The time that an aircraft is scheduled to depart from its parking position
SOSTScheduled On Stand TimeThe scheduled time at which the aircarf twill stop at the stand
STDScheduled Time of DepartureThe scheduled time at which an aircraft will become airborne.
STOTScheduled Take-Off TimeThescehduled take off time.
STTT
Scheduled Turn-round Time
Metric SOBT – SIBT
TLDT
Target Landing Time
Targeted Time from the Arrival management process at the threshold, taking runway se- quence and constraints into account. It is not a constraint but a progressively refined plan- ning time used to coordinate between arrival and departure management processes. Each TLDT on one runway is separated from other TLDT or TTOT to represent vortex and/ or SID separation between aircraft.
TOBT
Target Off-Block Time
The time that an Aircraft Operator or Ground Handler estimates that an aircraft will be ready, all doors closed, boarding bridge removed, push back vehicle available and ready to start up / push back immediately upon reception of clearance from the TWR
TSAT
Target Start Up Approval Time
The time provided by ATC taking into account TOBT, CTOT and/or the traffic situation that an aircraft can expect start up / push back approval
TTATarget Time of ArrivalAn ATM computed arrival time. It is not a constraint but a progressively refined planning time that is used to coordinate between arrival and departure management applications.
TTOT
Target Take Off Time
The Target Take Off Time taking into account the TOBT/TSAT plus the EXOT. Each TTOT on one runway is separated from other TTOT or TLDT to represent vortex and/ or SID separation between aircraft.
VTTVariable Taxi TimeThe estimated time that an aircraft spends taxiing between its parking stand and the runway or vice versa.
WAITWait timeThe time interval measured between the completed line-up and the ATC clearance for take-off.

I’m sure that there are more milestones, but I wanted to point out the relevance of the dozens of temporal milestones regarded to aircraft and airport operation, so measure them is basic for any airport dashboard. So we will count some of them in ours.

For more info:

Eurocontrol Lexicon. Eurocontrol website.

A-CDM Implementation Manual. Eurocontrol website.

Civil Aviation Safety Authority. Australian Government.