Target Off-Block Time (TOBT) What is TOBT? TOBT Definition (EUROCONTROL, A-CDM Manual version 4): The time that an Aircraft Operator (AO) or Ground Handler (GH) 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 Tower. Where do you find TOBT? Now: You can view and update your TOBT s in IDAHO and they are displayed on the Stand Entry Guidance System (SEGS), pier served stands only, for every flight at Actual in Block Time (AIBT) or 75 minutes before a departure. On remote stands or SEGS units with no display, the Dispatcher must check with their operation's department to confirm the current TOBT at the start of the aircraft turn. Following A-CDM; At -2 hours before the schedule, the TOBT of your flight will be automatically loaded in the Gatwick A-CDM portal. Any manual updates will be possible via this platform as well. Please see Fig.1 User profiles will be configurable based on your company and role. (Fig.1) Procedures Group DRAFT: 1
TOBTs will be displayed on the Stand Entry Guidance System (SEGS) for every flight at Actual in Block Time (AIBT) or 75 minutes before a departure. The countdown clock is in line with the latest TOBT update. Please see Fig.2 EZY5477 09:30 Z -020 (Fig. 2) Who is responsible for the TOBT input? Now: The Dispatcher is accountable for the TOBT update. The Operations Centre is responsible inputting any update. Following A-CDM, a TOBT update is a joint and coordinated effort between the Aircraft Operator and the Ground Handler. The Dispatcher is accountable for the update, the AO or GH is responsible for its input. Airlines have to ensure: the communication with the Flight Deck and relevant Airline Operational Control Centre (OCC) the co-ordination of internal working procedures between the Ground Handler and Aircraft Operator will have to be secured in the Service Level Agreement (SLA) How and when is the TOBT is automatically calculated? Now: Approximately 20 minutes before Expected Landing Time (ELDT) a TOBT (1) is generated at zoning of the aircraft. [This horizon could extend to -40 on receipt of EAT message] When the aircraft arrives on stand at Actual In Block Time (AIBT) a TOBT (2) is generated and it will be based on MTTT (Minimum Time to Turn). These MTTT s are regularly updated and Aircraft Operators are consulted for the most accurate times. If any requirement for a manual update arises, than the AO/GH can manually override TOBT (1) or TOBT (2) at any point and this manual input (TOBT3) will be the recorded TOBT. The automatic calculated TOBT shall not be before the scheduled off block time (SOBT) or filed flight plan time (EOBT). Following A-CDM: In line with European harmonisation, TOBT calculation will start automatically at 2 hours based on the filed flight plan departure time (EOBT) and will be continually improved based on zoning [EAT] and on arrival data. Please see ACDM_ Arrival data Sources Procedures Group Procedures Group DRAFT: 2
When can the TOBT be updated manually? Now: At any time. Following A-CDM: At any time a manual update can be input for differences of more than +/- 5 minutes of the latest TOBT. There is no obligation to confirm an automatic TOBT if the latter one is correct. Last TOBT update is at Target Start-up Approval Time TSAT* -5 minutes, to protect a stable pre-departure sequence. TOBT s that are updated past -5 minutes of the current TOBT should only be in exceptional circumstances, for example, last minute aircraft technical issues. How is the process of calculation for a night stop/day stop and towing? Now: For a night-stopping aircraft, Stand Entry Guidance System (SEGS) will start at 75 minutes to display the TOBT countdown. Following A-CDM: The TOBT process starts at -2 hours with the automatic calculation. TOBT can be automatically updated at ACGT (Actual Commence of Ground Handling time), when start of ground handling can be time stamped. At any time the TOBT can be manually input and will override any system calculation. Comment [IC1]: Update Neil Harvey For a day stopping aircraft the SEGS will pick-up a departing aircraft at the parking position at -75 minutes, the SEGS will than display TOBT. Following A-CDM: The TOBT process starts at -2 hours with the automatic calculation. (For aircraft which are not part of a direct turnaround and which do not park on their outgoing position, the TOBT is generated at off-block from the direct preceding position). At any time the TOBT can be manually input and will override any system calculation. Gatwick Airport Stand Planning team will be able to incorporate aircraft towing requirements into the Gatwick A-CDM portal and a future countdown clock on SEGS to clear stand for towing and departure time will be activated. Can TOBT be earlier than EOBT? Yes, you can enter a TOBT 10 minutes before your EOBT, to accommodate operational needs. More than 10 mins is not allowed and the TOBT will alert the Gatwick CDM Portal. See Fig.1 Procedures Group DRAFT: 3
Fig.1 What if the TOBT does not match EOBT? 1. If the TOBT is greater than EOBT + 10 minutes, the Aircraft Operator and/or Ground Handler will be informed by means of an alert and a DLA message will have to be sent.(fig.2) An alert will be indicating that the flightplan EOBT needs to be delayed by the Aircraft Operator in case the TOBT >10 minutes ahead of EOBT. 2. The EOBT is 15 minutes later, or more, than the TOBT (EOBT>15 minutes>tobt) Currently delay messages (DLA) are sent to the Network Manager (NMOC) by the Aircraft operator in case a flightplan EOBT needs delaying. This discrepancy between the EOBT and the TOBT will be flagged and the latest EOBT value will be assumed to overrule the TOBT value. An alert will be indicating that the flightplan EOBT automatically has overwritten the TOBT field in case the EOBT>15 minutes of TOBT. Procedures Group DRAFT: 4
3. The TOBT is more than 10 earlier than EOBT In line with European harmonisation the TOBT will be will need to be updated and an alert will be generated. Can a TOBT be deleted and what is the consequence? Following A-CDM; Yes, if the TOBT is deleted, the Target Start-up Approval Time (TSAT) is automatically deleted as well. If a new TOBT is known and updated the process shall continue, the person responsible for the TOBT has to enter a new TOBT. The effect will be that the flight will be out of departure sequence and TOBT must be updated requesting a new TSAT. Therefore the flight will be re-sequenced in the next available position. An alert will be raised to flag the deletion. At any point the TOBT can be filled in again when a new departure time is known, making sure the flightplan EOBT matches this TOBT. When will the TOBT require updating? Following A-CDM; in following cases: When the TOBT is unknown due to e.g. technical problems with the aircraft resulting in uncertain departure time. When the TOBT is set more than 10 min early than the EOBT. TOBT updates should be carefully input as this will cause instability of the predeparture sequence, hence the recommended number of TOBT updates after TSAT issue-time is 3. Every TOBT will update the last time with a 5 minute increment. Three updates will result in the requirement to delay the flightplan (DLA on EOBT) and hence this will result in a new EOBT which will be matched against a TOBT. According the Start-up Procedures (AIP* NATS AIS AD2-EGKK-1 2.20 Local Traffic Regulations) flight deck will call ATC at TOBT to report ready. If you are not ready at TOBT + 5 minutes and an update is not received within the next 5 minutes, the TOBT will require updating. According the Start-up Procedures (AIP*) ATC will call the flight deck to grant start-up clearance. (if TSAT is later than TOBT) If you don t act at TSAT + 5 minutes, the TOBT will require updating. When the flightplan is cancelled by the Aircraft Operator, the TOBT will be deleted, as there is no EOBT to match TOBT. Procedures Group DRAFT: 5
What happens with my TOBT in case of change of aircraft? Following A-CDM: if the aircraft is changed, a change message (CHG - type/registration) has to be issued and the TOBT remains in effect and is allocated to the new aircraft. What happens with my TOBT when the flightplan gets delayed by means of a DLA (delay) message? Following A-CDM: a delay message to the Network Manager Operations Centre (NMOC) will update the EOBT, which will flag a discrepancy between the TOBT and the EOBT in the Gatwick A-CDM portal. See previous What if the TOBT does not match EOBT? Procedures Group DRAFT: 6
When is the TOBT used to calculate first TSAT? Following A-CDM: At 40 minutes of the EOBT, the known TOBT at that point will be used for calculating the first pre-departure sequence. From this point on, TOBT updates should be carefully input as this will cause instability of the pre-departure sequence, hence the recommended number of TOBT updates after TSAT issue-time is 3. Will a TOBT update automatically update FIDS (Flight Information Display System)? Now: any TOBT later than 15 minutes is automatically published. Following A-CDM: Any TOBT changes later than 15 minutes will alert to publish on FIDS and depending on the Airline/Ground Handling Agent this may generate an automatic update of the FIDS, if so required. Can I indicate a priority to a flight by means of TOBT input, under the same area of responsibility (same Airline Operator)? Following A-CDM: It will be possible to indicate in the Gatwick A-CDM portal that a specific flight is prioritised for pre-departure sequence- purposes. ATC stays responsible for the TSAT. After the TSAT has been calculated, for flights within the same area of responsibility. TSAT can be switched in exceptional cases. These changes within the sequence can be coordinated with ATC, and in case of flights with CTOT, this must be adhered to despite the changes within the sequence. What if I am not ready at TOBT + 5'? Following A-CDM: If you are not ready at TOBT + tolerance + 5, an alert will be sent. You get another 5 to solve and re-input new TOBT before a C-DPI will be sent to NMOC. If the TOBT is deleted, the Target Start-up Approval Time (TSAT) is automatically deleted as well. If a new TOBT is known and updated the process shall continue, the person responsible for the TOBT has to enter a new TOBT. The effect will be that the flight will be out of departure sequence and TOBT must be updated requesting a new TSAT. Therefore the flight will be re-sequenced in the next available sequence. Are all flights operating in Gatwick part of this A-CDM process? E.g. General Aviation Flights? Following A-CDM: General Aviation flights are an integral part of process and have to be made aware of the consequences. They need to have the same platform and have to improve on flight planning accuracy. Therefore it is important is to brief these specific crews on the CDM process. Procedures Group DRAFT: 7
Will the pushback procedures change? Now: Pushback tugs are planned on SOBT (schedules). As there is no pre-departure sequence yet, the order of pushback clearance is not always clear and can cause inefficient use of resources, manpower and tugs. Following A-CDM: As On-Time-Departure (OTD) is one of the main drivers in the ACDM55 project, pushback tugs will be allocated to the aircraft based on TOBT. At TOBT the aircraft will call ready to ATC according the start-up procedures (AIP* NATS AIS AD2-EGKK-1 2.20 Local Traffic Regulations. If the difference between TOBT and TSAT is more than 30 minutes, collaborative decision making between the Aircraft Operator (AO) and the Ground Handler(GH) may facilitate the tug being allocated to another aircraft. The AO will decide to update the TOBT in line with new expected tug allocation. Tugs should stay with A/C until TOBT +5 if TOBT=TSAT. If the aircraft fails to call ready to ATC at this time, the TOBT will be deleted, and a new input is needed. How is TOBT accuracy and TOBT achievement measured? Now: TOBT accuracy is measuring how accurate TOBT is against Actual Start Request Time (ASRT) while TOBT achievement is measuring how the turnaround process is achieved, based on the minimum turnaround time (MTTT). Both are key performance indicators and will be communicated via the Gatwick A-CDM portal. Following A-CDM: TOBT accuracy will be measured against Actual Start Request Time (ASRT), this is the moment when the flight deck contacts ATC to call ready. The consequences of inaccuracy could be reflected in allocating delay codes; 1. When an aircraft is fully ready at TOBT, and cannot reach ATC before TOBT+5, the allocated delay could be ATC. 2. When an aircraft is fully ready at TOBT, and cannot reach ground staff before TOBT+5, the allocated delay could be Ground Handling 3. When an aircraft is not ready before TOBT+5, the allocated delay could be flight deck. 4. When a TSAT is later than TOBT and the delay is taken at the stand (no Push &Hold) then the allocated delay could be Ground Movement Congestion (GMC). Can the flight deck update TOBT directly? Following A-CDM: a TOBT update is a joint and coordinated effort between the Flight Deck and the Ground Handler. The Dispatcher is accountable for the update, the AO or GH is responsible for its input. After the aircraft is fully closed-up, the flight deck now have responsibility to update the TOBT. Please refer to return to stand. Procedures Group DRAFT: 8