Turnaround KPIs
The turnaround process, the critical window between an aircraft’s landing and its subsequent departure, involves a complex choreography of ground handling, fueling, cleaning, catering, and passenger boarding.
To orchestrate this process seamlessly, airports and airlines rely on Airport Collaborative Decision Making (A-CDM) and a precise set of time-based Key Performance Indicators. This guide consolidates the essential turnaround acronyms and metrics into a logical, chronological framework to help airport operators monitor, analyze, and optimize every stage of the turnaround lifecycle.
Foundational concepts: The ecosystem of efficiency
Before diving into the chronologically ordered KPIs, it is crucial to understand the overarching frameworks and infrastructure supporting turnaround management.
- A-CDM (Airport Collaborative Decision Making): A strategic concept aimed at improving air traffic management by enabling partners (airport operators, aircraft operators, ground handlers, and ATC) to share timely and accurate information. A-CDM reduces delays, enhances predictability, and optimizes resource utilization.
- TCMS (Turnaround Management System): The central software solution used by airports and ground handlers to coordinate, track, and manage all events occurring during an aircraft’s turnaround process.
- ToF Sensor (Time-of-Flight Sensor): A hardware technology increasingly deployed at airport gates. ToF sensors emit light pulses to measure distances, allowing automation systems to detect the precise presence of aircraft, ground support equipment (GSE), and personnel in real time without compromising individual privacy.
Phase 1: Inbound & arrival
The turnaround process begins long before the aircraft hits the tarmac. Precise inbound tracking ensures ground crews are positioned and ready.
- LDT (Landing Time): The baseline term for when an aircraft makes contact with the runway.
- ALDT (Actual Landing Time): The exact time that an aircraft wheels touch down on the runway.
- ELDT (Estimated Landing Time): The constantly updated time that the aircraft is projected to land, based on its current flight progress.
- TLDT (Target Landing Time): A targeted arrival time calculated by Air Traffic Control (ATC) or sequencing systems to optimize the arrival flow.
- AAR (Airport Acceptance Rate): The number of arrivals an airport can safely accommodate per hour. This directly dictates landing slots and influences ELDT/TLDT calculations.
Phase 2: In-block & the core turnaround
Once the aircraft exits the runway, it transitions to the gate or stand. This phase represents the heart of ground operations.
Taxiing In
- Taxi-In Time: The duration of time an aircraft spends moving from the runway to its designated parking position.
- EXIT (Estimated Taxi-In Time): The predicted time required for the aircraft to taxi from the runway to the stand.
- AXIT (Actual Taxi-In Time): The precise duration from runway touchdown (ALDT) to gate arrival.
Arriving at the Stand
- IBT (In-Block Time): The moment an aircraft arrives at its parking position and the wheel chocks are applied.
- SIBT (Scheduled In-Block Time): The planned arrival time according to the airline's published schedule.
- EIBT (Estimated In-Block Time): The predicted time the aircraft will arrive at the block (calculated as ALDT + EXIT).
- AIBT (Actual In-Block Time): The exact timestamp when the aircraft stops at the gate and chocks are placed. This marks the formal start of the turnaround.
Ground handling & turnaround execution
- TAT (Turnaround Time): The total elapsed time between an aircraft’s arrival at the gate and its departure from the gate (from AIBT to AOBT).
- STTT (Scheduled Turnaround Time): The allocated, planned duration for the turnaround according to the schedule.
- ETTT (Estimated Turnaround Time): The continuously updated forecast of how long the ground operations will take, based on real-time ground handling progress.
- ATTT (Actual Turnaround Time): The real duration it took to complete all ground handling processes.
- Block Time: The total time elapsed from the moment the aircraft moves from its departure gate (chocks off) until it stops at its arrival gate (chocks on) at the destination. Minimizing turnaround ensures block times stay on track across multi-leg flights.
Phase 3: Off-block & departure readiness
As ground handling wraps up, the focus shifts to securing departure clearance and pushing back the aircraft.
Target setting
- OBT / SOBT (Off-Block Time / Scheduled Off-Block Time): OBT is the generic term for departure from the gate. SOBT is the scheduled time the aircraft is expected to push back.
- EOBT (Estimated Off-Block Time): The time the aircraft operator estimates the aircraft will be ready to move, assuming no ATC constraints.
- TOBT (Target Off-Block Time): A critical A-CDM metric. It is the exact time the aircraft operator or ground handler expects the aircraft to be fully ready, doors closed, passenger jetway removed, and ready for pushback.
- TSAT (Target Start-Up Approval Time): The time provided by Air Traffic Control (ATC) indicating when an aircraft can expect the official approval for engine start-up and pushback. TSAT takes into account TOBT, overall airport traffic, and European/regional slot allocations (CTOT).
Departure windows & actual pushback
- CTOT (Calculated Take-Off Time): Also known as a "slot", this is a highly specific take-off time window issued by central flow management (like Eurocontrol) to regulate airspace capacity.
- AOBT (Actual Off-Block Time): The precise time the aircraft releases its brakes and begins to push back or taxi away from the gate. This marks the formal end of the turnaround process.
Phase 4: Outbound & take-off
The final phase monitors the aircraft's movement from the gate back to the runway for departure.
Taxiing out
- Taxi-Out Time: The duration spent moving from the departure stand to the runway.
- EXIT (Estimated Taxi-In Time): The predicted time required for the aircraft to taxi from the runway to the stand.
- AXIT (Actual Taxi-In Time): The precise duration from runway touchdown (ALDT) to gate arrival.
Take-Off
- TOT (Take-Off Time): The overarching term for when the aircraft leaves the ground.
- TTOT (Target Take-Off Time): The ideal take-off time calculated by A-CDM systems to ensure optimal runway sequencing (TOBT + EXOT).
- ETOT (Estimated Take-Off Time): The predicted take-off time based on real-time progress at the gate and taxiway.
- ATOT (Actual Take-Off Time): The exact timestamp when the aircraft lifts off the runway.
- ADT (Actual Departure Time): Frequently used interchangeably with ATOT, referencing the definitive time the flight became airborne.
Phase 5: Measuring success
- OTP (On-Time Performance): The ultimate North Star metric for airports and airlines. A flight is traditionally considered "on time" if its actual arrival or departure (AIBT/AOBT) occurs within 15 minutes of the scheduled time (SIBT/SOBT). Maximizing OTP relies entirely on flawless execution across all the previous KPIs.
Conclusion: Driving turnaround efficiency
Mastering the chronological flow of these KPIs is only half the battle; the real challenge lies in gathering accurate, real-time data to measure them. Manual timestamps and legacy tracking systems often result in delayed information, leading to reactive decision-making and costly ground delays.
This is where Isarsoft transforms airport operations. Isarsoft’s advanced Turnaround Management Solution leverages cutting-edge video analytics to automatically detect, measure, and analyze the milestones of the turnaround process. By turning existing airport camera infrastructure into intelligent sensors, Isarsoft provides real-time visibility into ground support equipment (GSE) readiness, jetway connections, refueling states, and precise AIBT/AOBT tracking.
With highly accurate data feeding directly into your Turnaround Management Systems (TCMS) and A-CDM workflows, Isarsoft eliminates blind spots, optimizes resource allocation, and drastically improves your On-Time Performance (OTP).
Learn more about how video analytics can revolutionize your ground efficiency.