Scheduling and planning features for Airlines

1. Introduction

Leon is a flight operations platform that started in business and charter aviation and has grown into a full toolset for airlines and scheduled operators. For an airline the day starts long before the first departure: a season schedule has to be built, tails have to be assigned, commercial and ground systems have to be told about every change, and the operation then has to be followed in real time.

This article walks through how Leon supports that chain end to end. Leon is designed to be the operational source of truth and to exchange data with the specialised systems airlines already run – reservations, departure control, cargo, flight planning, load control, air traffic flow management and fatigue risk management – rather than to replace them.

2. SCHED – building and managing the schedule

SCHED is the Leon module for creating and managing flight schedules. It is designed primarily for airlines and scheduled operators. Schedules can be prepared and refined in SCHED without affecting the operation: new flights are not visible to the OPS team until they are published.

Main view and schedule versions

The main view is split into two parts. The upper section, Versions, shows schedules that belong to a schedule version but have no aircraft yet. The lower section, Aircraft schedules, shows flights assigned to aircraft – both the real fleet and virtual aircraft, which let planners build a programme before the tail is known.

• Versions – each version has a name, a client (for example a tour operator) and a description. Several versions can be previewed side by side; versions assigned to the same aircraft are shown on separate lines, and unassigned versions appear as TBA lines.

• Time reference – the view can be switched between UTC and Base Time, and airports can be shown as IATA or ICAO codes.

Creating schedules

• Import – upload a schedule from an SSIM or XLS file (the XLS must follow the Leon export format). Re-uploading a changed file replaces the existing schedule in that version.

• Manual creation in two modes: To date (a From–To period) or Block hours, where Leon limits the number of rotations to the block hours allowed. For example, with a 30-hour limit and 6:25 per rotation, Leon builds four rotations (25:40).

• Weekly, biweekly or triweekly rotation, operating days, multi-leg schedules with a Day Shift per leg, and entry in UTC, Base Time or Local Time (with protection against Daylight Saving Time change windows).

• Optional commercial fields used in SSM/ASM messages: IATA Service Type, code-share flight number, PRBD, PRBM, meal service note, Traffic Restriction (DEI 8), terminals and handling agents for ADEP and ADES.

• Tags, which carry over to the trip in OPS once the schedule is published.

Working with flights

• Select Flights – filter by version, date range, days, aircraft, flight numbers, airport, ADEP/ADES and tags.

• Publish – publishes whole pairings (not single legs) to OPS, with the aircraft chosen at creation or another existing aircraft. On publication Leon fills in the Flight time from block time minus the airports' taxi times. Leon groups legs into trips by aircraft and rotation, with up to 20 legs per trip.

• Modify – shift times, change block time, ADEP/ADES slots, aircraft, flight number, airports, alternate, ferry status and tags. Separate tabs cover Pairings, Trip data (client, trip type, option, commercial) and a Checklist tab for changing checklist item statuses on many published flights at once.

• Swap Aircraft – swap the flights of two aircraft of the same type in one step.

• Delete – removes planned or published flights (published flights are also removed from OPS).

• Show in OPS – jump from a published pairing to the OPS Table view, and back again.

• Export – SSIM (.txt) for published flights, or Excel (.xls).

For more information: Sched

3. Fleet Planning

Fleet Planning is the view for assigning aircraft to scheduled trips that do not yet have a tail, or for changing the aircraft on trips that already do. It shows all scheduled trips in a chosen date range, sorted by date, with the aircraft colour from fleet settings on both sides of each trip.

• Reassign aircraft on several trips and save them together.

• On saving, Leon checks for overlapping flights, maintenance conflicts, reservation issues, airport discontinuity and crew rating warnings caused by type changes. Details are shown in a tooltip, and changes can still be saved with Save ignoring warnings when the planner accepts the risk.

• The Aircraft filter supports text search, labels, sorting, active/all status and drag-and-drop ordering, plus presets that can be private or shared with other users.

• An additional filter narrows the view by airport and by trip departure days.

For more information: New Fleet Planning

4. Fleet Auto Planner

The Fleet Auto Planner assigns tails to a schedule automatically. Its principle is simple: find the assignment that minimises total repositioning time for all aircraft, while ensuring every flight can actually be flown. It can be opened from OPS, under the menu in the lower-right corner (Batch Flight Operations › Fleet Auto Planner), or from SCHED, with the FLEET AUTO PLANNER button.

How it works

• The planner chooses a date interval and an aircraft type. All flights of that type are included, including those assigned only to the type and not to a specific tail.

• Include ferry decides whether existing ferry flights are optimised like any other flight or left untouched.

• Confirmed maintenance blocks the aircraft; maintenance with status Option is ignored.

• Repositioning (ferry) legs are not added automatically, so the planner can add them manually while considering factors such as slot availability. The generated plan marks where a ferry flight will be needed, with its route and estimated flight time calculated from the aircraft's performance model, including winds, and flags cases where there is not enough time for it.

• Optimize Plan only calculates a proposal; nothing changes until the planner clicks Update. Updating replaces all existing aircraft assignments for the flights in the selected period and cannot be undone.

For more information: Fleet Auto Planner

5. SSIM, ASM and SSM messaging

SSIM (IATA Standard Schedules Information Manual) defines the formats airlines use to exchange schedules. Leon uses these standards to keep the systems around the airline in sync with the operational schedule:

Who receives the messages

• DCS – Departure Control System

• PSS – Passenger Service System (reservations and inventory)

• CMS – Cargo Management System

• Flight planning software and other partners that consume SSIM/ASM/SSM – for example the eTechLog8 electronic tech log receives schedules and changes from Leon this way.

Messages are delivered by email or FTP/FTPS. Airlines with a SITA (SITATEX) or ARINC (AvinetMail) subscription can configure a mailbox in Leon so that the messages reach the recipients as Type B messages on the SITA or ARINC networks.

Configuration (Settings › SSIM)

• How many days ahead flights are sent, and which ICAO aircraft types and trip types are included.

• Send SSIM/SSM/ASM automatically – choice of scenario, including SSM & ASM.

• ASM threshold, default To/From email addresses, FTP/FTPS host, port, credentials and directory.

• Custom data elements DEI 900–999 (currently aircraft registration), in addition to standard elements such as DEI 3, 4, 5 and 8 and the IATA Service Type.

• Prerequisites: the airline's IATA code (General Settings), aircraft and virtual aircraft IATA codes, and PRBD/configuration on each aircraft. Leon warns in SCHED and by email if anything is missing.

The SSM & ASM scenario

• SSM is sent for a new flight whose STD is more than 24 hours away, and for updates to such flights.

• ASM is sent once the STD is within 24 hours; after the first ASM, each further change triggers another ASM.

Smart message types

For automatic sending, Leon compares each flight with what it sent last time and sends only what changed:

Manual sending is done from the DCS and PSS items of the OPS checklist (NEW, RPL or CNL). After sending, the item turns to Sent, and switches to ? if the flight changes again – so OPS can see at a glance which systems are out of date.

For more information: SSIM

6. LDM messages in Flight Watch

Leon can receive LDM (Load Message, IATA AHM 583) messages and save their content directly on the flight, so load figures no longer have to be typed in by hand.

• A dedicated mailbox is configured in Settings and linked in the Cargo configuration. Leon scans it every 10 minutes.

• Each message is matched to a flight by flight number, registration, date and airports. Leon accepts the ICAO designator, the IATA designator or the bare flight number, so AB123 and ABC123 are both recognised.

• Cargo, mail, baggage and passenger data are saved in Flight Watch, including total cargo mass (in the fleet weight unit), ULD identifiers and weights, C/B/M codes and notes.

• If ULD Bays (loading points) are configured for the aircraft, the distribution is also written to Load Distribution and can be reviewed in the OPS checklist. Leon also supports airlines that send the per-compartment breakdown in the LDM instead of a CPM.

• Unmatched messages go to an error queue for manual linking, units are converted automatically, and an audit trail is kept in the message history.

For more information: Cargo — LDM message import and automatic in-flight data saving

7. Integrations with airline systems

Besides the SSIM, ASM, SSM and LDM messaging described above, Leon can be integrated with a range of specialised systems used by airlines and scheduled operators. Each integration keeps the partner system working from the same, current schedule and crew data held in Leon, without a second data entry:

• N-Flight Planning (NAVBLUE) – flight planning; Leon sends the schedule, aircraft, flight rules and assigned crew so flight plans are built from the Leon schedule.

• FliteBrief (Jeppesen) – crew briefing and flight monitoring; Leon sends schedules and crew composition and can download Journey Log data back.

• Evionica Weight & Balance – digital load and trim sheets prepared for the flights scheduled in Leon.

• Eurocontrol – aircraft movements; actual times (CTOT, ATD, EET, ETA, ATA) are fed automatically into Flight Watch.

• SAFTE-FAST – crew fatigue analysis of rosters and duties, shown directly in the Crew Timeline.

• FRMSc SAFE – crew fatigue evaluation; Leon sends pilots' duties, standby and reserve data automatically or on demand.

8. Summary

Together these features let an airline keep one operational schedule in Leon and have every connected system – commercial, ground, planning, load control and safety – work from the same, current data.

Last updated: October 18, 2026