Config File Reference

This page documents the public and advanced-user configuration surface for alb-config.json.

A sample file is available here: alb-config.json

Overview

alb-config.json is the live operational ALB config.

Important packaging facts:

• EuroScope should load ALB.dll
• ALB.dll loads ALBCore.dll
• alb-config.json is the live config and must not be silently overwritten by the loader
• alb-config.default.json is the shipped template/default file

Place alb-config.json in the same plugin folder as ALB.dll and ALBCore.dll.

Current config version support

The current ALB runtime supports:

• configFormatVersion: 2
• configFormatVersion: 3

For new configs, use:

"configFormatVersion": 3

Encoding note

The plugin uses the EuroScope font, which is based on ANSI/Windows-1252.

If you use special symbols in static tag fields, save the JSON file using ANSI encoding.

Scope of this page

This page documents the operational and advanced-user config surface.

A live config file may also contain additional developer-only keys used for internal validation workflows. Those are intentionally not described on the public documentation site.

Disabling blocks with -off / _off

When loading timelines and tagLayouts, any key ending with -off or _off (case-insensitive) is skipped.

Examples:

• "EKCH 04L/04R-SI_off"
• "Expanded-off"

This disable pattern does not apply globally to all config keys. For many top-level settings, the runtime reads only the exact expected key name.

Top-Level Options

Property	Type	Default	Description
configFormatVersion	int	required in practice	Config schema version. Use 3 for new configs.
openAutomatically	bool	true	Opens the ALB window when the config is loaded.
logging	bool	false	Enables ALB runtime text logging.
scratchpadRunwayOverride	bool	false	Enables scratchpad runway override parsing for assignedRunwayOverride.
timeSyncBeacons	bool	false	Enables time-sync beacon support.
timelineSort	string	targetFixEta	Default timeline sort mode. Accepted values include target / tfe and landing / lde / lnd.
eatModeOnStartup	string	AR	Startup EAT mode, applied only during the initial config load. Accepted values are AR, TF, and LT case-insensitively.
etaModeOnStartup	string	ES	Startup ETA source, applied only during the initial config load. Accepted values are ES and ALB case-insensitively.
holdEatWriteOnStartup	bool	false	Startup state for local HLW, applied only during the initial config load.
holdEatLockWindowMinutes	int	5	Hold/EAT lock window in minutes. Applied only if greater than 0.
holdEatRecentChangeMinutes	int	2	Recent-change window for hold/EAT logic in minutes. Applied only if greater than 0.
aircraftLastSeenSweepMinutes	int	2	How often ALB sweeps persisted aircraft state for expiry. Applied only if greater than 0.
aircraftOfflineResetMinutes	int	5	Threshold after which unseen aircraft have persisted sequencing/state cleared. Applied only if greater than 0.
housekeeping	object	defaults below	Startup housekeeping settings for ALB logs and backend recording folders.
soundMute	object	all false	Startup mute state for ALB sounds.
layout	object	defaults below	EAT display precision/suffix formatting settings.
backendSeqSync	object	defaults below	Backend sequence synchronization transport mode and TX-budget settings.
backendPeerHealth	object	defaults below	Passive backend peer update-cycle health monitoring and warning thresholds.
glEatCombiDisplay	object	defaults below	Optional display mapping for the combined glEatCombi field.
timelines	object	required	Timeline definitions.
tagLayouts	object	required	Tag layout definitions.
tmaAreas	array	optional	TMA polygon definitions.
airports	object	optional	Airport-specific fallback circles, runway metadata, and advanced airport tuning.

Startup-only policy keys

eatModeOnStartup, etaModeOnStartup, and holdEatWriteOnStartup are read only during the initial config load.

That means:

• they are useful for your preferred startup baseline
• they do not force the runtime back to those values on every Reload config
• missing or invalid values fall back independently to safe defaults

Current independent fallbacks are:

• eatModeOnStartup -> AR
• etaModeOnStartup -> ES
• holdEatWriteOnStartup -> false

Housekeeping

housekeeping controls startup cleanup of ALB runtime files.

Example:

"housekeeping": {
  "enabled": true,
  "textLogRetentionDays": 16,
  "textLogMaxFilesPerFamily": 20,
  "backendRecordingRetentionDays": 16,
  "backendRecordingMaxFolderMb": 500
}

Property	Type	Default	Accepted range	Description
enabled	bool	true	n/a	Enables runtime housekeeping.
textLogRetentionDays	int	14	1-365	Retention period for ALB text log families.
textLogMaxFilesPerFamily	int	20	5-500	Max number of files kept per text-log family.
backendRecordingRetentionDays	int	14	1-365	Retention period for backend recording material.
backendRecordingMaxFolderMb	int	500	50-10000	Max size for backend recording folder before pruning.

If values are invalid, the runtime falls back to defaults and logs a warning. Out-of-range integers are clamped.

Sound Mute

soundMute sets the startup mute state for ALB audio categories.

Example:

"soundMute": {
  "all": false,
  "missed": false,
  "ar": {
    "all": false,
    "unselected": false
  }
}

Property	Type	Default	Description
all	bool	false	Mutes all ALB sounds.
missed	bool	false	Mutes missed-approach/go-around related sounds.
ar.all	bool	false	Mutes all arrival-rate related sounds.
ar.unselected	bool	false	Mutes arrival-rate sounds for unselected/non-focused contexts.

Layout

layout controls how EAT-style times are displayed in the timeline.

Example:

"layout": {
  "EatDisplayPrecisionSec": 15,
  "EatDisplayRecalcPeriodSec": 15,
  "EatDisplayIntervalChars": ["", "a", "b", "c", "d"]
}

Property	Type	Default	Accepted values	Description
EatDisplayPrecisionSec	int	60	15 or 60	Display precision for EAT-style time presentation.
EatDisplayRecalcPeriodSec	int	0	0-600	Display regeneration throttle. 0 means automatic.
EatDisplayIntervalChars	string[]	["","a","b","c","d"]	up to 5 one-character strings	Suffix characters used by HHMMx / HH:MMx formats.

Precision and suffix behavior

If EatDisplayPrecisionSec is 60, ALB displays normal minute precision.

If EatDisplayPrecisionSec is 15, ALB uses five second-bucket suffix slots across each minute. With the default suffix characters this behaves roughly as:

• 00:00 to 00:07.5 -> no suffix
• 00:07.5 to 00:22.5 -> a
• 00:22.5 to 00:37.5 -> b
• 00:37.5 to 00:52.5 -> c
• 00:52.5 to 01:00 -> d

Recalc throttle

EatDisplayRecalcPeriodSec controls how often display strings are regenerated.

• 0 = automatic
• automatic means 15 seconds when precision is 15
• automatic means 1 second when precision is 60

Backend SeqSync

backendSeqSync controls backend sequence synchronization load-management.

This block affects how ALB sends canonical backend sequence state to peers. It does not change FMR ownership, EAT:AR versus EAT:LT, scratchpad fallback, or the local sequencing algorithms themselves.

Example:

"backendSeqSync": {
  "mode": "normal",
  "txMaxSet2PerSecond": 10,
  "txMaxSet2PerPoll": 10,
  "txQueueMaxAgeSec": 30,
  "authorityLeadMinutes": 10
}

Accepted mode values:

• normal
• throttled
• horizon
• suspend

Fallback behavior:

• missing mode falls back to normal
• malformed or unknown mode falls back to normal

Property	Type	Default	Accepted range or values	Description
mode	string	normal	normal, throttled, horizon, suspend	Backend seqsync transport mode. normal is immediate in steady state.
txMaxSet2PerSecond	int	10	1-200	Per-second budget for queued canonical SET2 transmission. Used by throttled, horizon, suspend recovery, and temporary normal recovery drain.
txMaxSet2PerPoll	int	10	1-200	Per-poll budget for queued canonical SET2 transmission. Used by the same queued or recovery paths as above.
txQueueMaxAgeSec	int	30	1-600	Queue age budget for backend seqsync queue handling.
authorityLeadMinutes	int	10	1-60	Horizon relevance window in minutes. Used by horizon to distinguish near-horizon traffic from far-floating traffic.

Operational notes:

• normal is immediate in steady state
• throttled, horizon, suspend, and temporary recovery drain use the TX queue budgets
• horizon may suppress far-floating canonical candidates while keeping operationally relevant or uncertain aircraft canonical
• suspend suppresses normal canonical SET2 TX, but operational DEL remains allowed and bounded
• returning from throttled or horizon to normal uses temporary bounded recovery drain until inherited queue backlog is empty

Backend Peer Health

backendPeerHealth controls passive backend peer update-cycle health monitoring.

This is an advanced diagnostic block. It does not change FMR ownership or canonical seqsync rules. It helps the FMR detect when a peer appears slow to apply shared backend updates and surfaces backend-only warn or recover events.

Example:

"backendPeerHealth": {
  "enabled": true,
  "warnAverageMs": 333,
  "recoverAverageMs": 200,
  "windowSec": 30,
  "consecutiveWarnWindows": 3,
  "consecutiveRecoverWindows": 2,
  "repeatWarnCooldownSec": 60
}

Property	Type	Default	Accepted range	Description
enabled	bool	true	n/a	Enables passive backend peer health monitoring.
warnAverageMs	int	333	100-5000	Average cycle threshold above which ALB starts treating a peer cycle window as slow.
recoverAverageMs	int	200	50-warnAverageMs	Average cycle threshold below which ALB may treat the peer as recovered.
windowSec	int	30	10-300	Measurement window length in seconds.
consecutiveWarnWindows	int	3	1-10	Number of bad windows required before warning.
consecutiveRecoverWindows	int	2	1-10	Number of good windows required before recovery.
repeatWarnCooldownSec	int	60	30-600	Cooldown before repeat warnings may be sent again.

Operational notes:

• these warnings are passive monitoring, not transport control
• warnings are backend-only and intended to help the FMR notice slow peer update cycles
• .alb seqsync status can show peer-health summary fields when this monitoring is enabled

glEatCombiDisplay

This block controls what the glEatCombi field shows depending on arrival state, hold state, and recent passage timing.

Example:

"glEatCombiDisplay": {
  "unknownState": "SwitchGainLooseEat",
  "unsequencedState": "SwitchGainLooseEat",
  "sequenced1State": "GainLoose",
  "sequenced2State": "Eat",
  "frozen1State": "Countdown",
  "frozen2State": "Countdown",
  "switchPeriodSec": 2,
  "holdXSec": 120,
  "holdGtXState": "Eat",
  "holdLeXState": "Countdown",
  "afterPassYMinutes": 2,
  "afterPassFirstYState": "DeltaAtPassage",
  "afterPassAfterYState": "Blank"
}

Accepted state values are case-insensitive and normalized. Common values:

• GainLoose or GL
• Eat
• Countdown or CD
• DeltaAtPassage or Delta
• SwitchGainLooseEat
• Blank

Property	Type	Description
unknownState	string	Display when arrival state is unknown.
unsequencedState	string	Display when aircraft is unsequenced.
sequenced1State	string	Display for sequenced state 1.
sequenced2State	string	Display for sequenced state 2.
frozen1State	string	Display for frozen state 1.
frozen2State	string	Display for frozen state 2.
switchPeriodSec	int	Cycling period for SwitchGainLooseEat. Values below 1 are clamped to 1.
holdXSec	int	Hold threshold in seconds. Values below 0 are clamped to 0.
holdGtXState	string	Display while in hold and remaining time is greater than X.
holdLeXState	string	Display while in hold and remaining time is less than or equal to X.
afterPassYMinutes	int	After-passage window length in minutes. Values below 0 are clamped to 0.
afterPassFirstYState	string	Display in the first Y minutes after passage.
afterPassAfterYState	string	Display after the first Y minutes after passage.

Operational notes:

• holdXSec and holdGtXState seed the local runtime hold-display control on startup and on a successful config reload
• the top-row hold-display button then lets each client adjust that threshold and pre-threshold hold display locally at runtime
• the normal hold-display button cycle is Eat -> GainLoose -> SwitchGainLooseEat -> Blank -> back to Eat
• holdLeXState is the inside-threshold display and is normally kept as Countdown
• unsupported holdGtXState values are normalized to Blank

The hold-display button uses compact labels such as:

• 2 EAT
• 2 GL
• 2 SW
• 2 ---

The number is the minutes before EAT where ALB switches to countdown. The suffix shows what glEatCombi displays while the aircraft is still farther out than that threshold.

Timelines

timelines maps a timeline id to a timeline definition.

Property	Type	Default	Description
targetFixes	string[]	required	Aircraft expected to pass one of these fixes are shown in the timeline. Exactly two fixes create a dual timeline unless forceSingleTimeline is true.
tagLayout	string	none	Tag layout id to use. Must exist in tagLayouts.
viaFixes	string[]	[]	Optional via-fix lanes. The placeholder "-----" can be used as a visual separator.
ArrivalScenarios	object	{}	Optional legacy scenario-name to integer-array mapping. Retained for compatibility/history; not recommended as the normal operating method. Arrays must match the number of non-placeholder via-fixes.
destinationAirports	string[]	[]	Optional destination ICAO filter. If non-empty, only matching destinations are included.
runways	string[]	[]	Optional runways relevant for this timeline.
defaultTimeSpan	uint	30	Initial visible timeline span in minutes.
forceSingleTimeline	bool	false	Forces a single timeline even when two target fixes are configured.
viaFixColors	string[]	palette	Optional custom RGB colors for real via-fix lanes.

Notes on ArrivalScenarios

• Operational note: ArrivalScenarios is retained for compatibility and history. Scenarios are no longer part of the recommended normal ALB workflow. Current operation should normally use EAT:LT landing-timeline monitoring and correction instead of scenario switching.
• The loader reads the key exactly named ArrivalScenarios
• alternate scenario blocks under other names are ignored
• placeholder via-fixes such as "-----" do not consume scenario values
• JSON order is preserved for scenario display menus

Tag Layouts

tagLayouts maps a layout id to a layout definition.

Two formats are supported:

1. legacy array format
2. object format with metadata plus items

Recommended format:

"Maestro-Feeder": {
  "hideDeselectedViaFixes": true,
  "timelineLayout": "Feeder",
  "timelineSort": "targetFixEta",
  "items": [
    { "source": "callsign", "width": 8 }
  ]
}

Layout properties

Property	Type	Default	Description
hideDeselectedViaFixes	bool	false	If true, aircraft in deselected via-fix lanes are hidden from the timeline.
timelineLayout	string	runtime default	Layout hint. Accepted values include runway and feeder.
timelineSort	string	runtime default	Optional per-layout sort mode.
items	array	required	Ordered list of tag items.

Tag Item Properties

Property	Type	Default	Description
source	string	""	Source field to render.
width	uint	1	Reserved character width.
rightAligned	bool	false	Right-aligns the rendered value.
isViaFixIndicator	bool	false	Colors the field using the via-fix lane color.
defaultValue	string	""	Fallback/default value, especially for static.
format	string	""	Optional time formatting override for time-backed sources.

format strings for time values

Supported format values are:

Format	Width	Meaning
HHMM	4	UTC time as 2359
HH:MM	5	UTC time as 23:59
HHMMSS	6	UTC time as 235959
HH:MM:SS	8	UTC time as 23:59:59
HHMMx	5	HHMM plus optional EAT precision suffix
HH:MMx	6	HH:MM plus optional EAT precision suffix

If a recognized format is present, ALB infers the effective field width from the format, so the explicit width value is no longer the controlling width.

Common time-capable sources for format

These sources can use a format string:

• estimatedLandingTime
• estimatedLandingTimeEs
• estimatedLandingTimeSso
• estimatedLandingTimeAlb
• plannedLandingTime
• plannedLandingTimeEs
• plannedLandingTimeSso
• plannedLandingTimeAlb
• underlyingEAT
• underlyingEAThms
• underlyingEATEs
• underlyingEATAlb
• viaFixETO
• viaFixETOhms
• timelineAnchor
• timelineAnchorHms

Tag Item Sources

Below are the common operational and advanced layout sources used by the current runtime.

Source	Meaning
static	Static text from defaultValue.
callsign	Aircraft callsign.
ATCShort	Tracking controller short id.
ATCLong	Tracking controller long id.
assignedRunway	Assigned landing runway.
assignedRunwayOverride	Scratchpad-based runway override.
assignedStar	Assigned STAR.
aircraftType	ICAO aircraft type.
aircraftWtc	Wake turbulence category.
minutesBehindPreceedingRounded	Spacing behind the preceding aircraft in rounded minutes.
timeBehindPreceeding	Spacing behind the preceding aircraft in mm:ss.
remainingDistance	Remaining distance to target fix in NM.
remainingDistance1d	Remaining distance with one decimal place.
distanceGapNmToPrevious	NM spacing/gap to the previous aircraft.
viaFixDistNmToGo	Remaining NM to the via-fix.
viaACToViaFixSec	Seconds from aircraft to via-fix.
viaFixToLandingSec	Planned seconds from via-fix to landing.
viaFixToLandingSecEs	ES-based via-fix-to-landing seconds.
viaFixToLandingSecSso	SSO/ALB-based via-fix-to-landing seconds.
estimatedLandingTime	Active estimated landing time.
estimatedLandingTimeEs	ES landing ETA branch.
estimatedLandingTimeSso / estimatedLandingTimeAlb	SSO/ALB landing ETA branch.
plannedLandingTime	Active planned landing time.
plannedLandingTimeEs	ES planned landing time.
plannedLandingTimeSso / plannedLandingTimeAlb	SSO/ALB planned landing time.
underlyingEAT	Active underlying EAT display value.
underlyingEAThms	Underlying EAT with seconds.
underlyingEATEs	ES-side underlying EAT branch.
underlyingEATAlb / underlyingEATSso	SSO/ALB-side underlying EAT branch.
glEatCombi	Combined gain/lose and EAT field.
viaFixLooseGain	Via-fix gain/lose display.
landingLooseGain	Landing/threshold-based gain/lose display.
viaFix	Via-fix lane.
viaFixETE	Estimated time enroute to via-fix.
viaFixETO	Estimated time over via-fix.
viaFixETOhms	Estimated time over via-fix with seconds.
viaFixSeqIndexCurrent	Current per-via-fix sequence index.
viaFixSeqIndexFixed	Fixed per-via-fix sequence index.
landingSeqIndexCurrent	Current landing sequence index.
landingSeqIndexFixed	Fixed landing sequence index.
targetFix	Active target fix for the aircraft.
targetFixEta	Estimated time over target fix.
targetFixATCTime	Estimated time over target fix including delay logic.
timelineAnchor / timelineAnchorHms	Active timeline anchor time used for ordering/display.
timelineAnchorSource	Source of the timeline anchor.
etaSource	Current ETA branch/source identifier.
holdingFix	Holding fix if available.
holdingEAT	Hold-related EAT text.
holdingEATm	Manual-hold-EAT marker.
holdPhase	Holding phase indicator.
FlightPhase	Determined flight phase.
ArrivalState	Determined arrival state.
inboundGrouping	Current inbound grouping bucket.
arrivalSeqNo	Raw arrival sequence number.
arrivalSeqMin	Minimum airborne arrival sequence number.
arrivalSeqMax	Maximum assigned arrival sequence number.
arrivalSeqDisp	Display sequence number.
arrivalSeqFrontier	Sequencing frontier marker.
obsNote3	3-character observation/note abbreviation.
bookingStatus	Backend booking/event-slot status text.
acno	Internal aircraft ordinal number.
isPastViaFix	Y/N flag for via-fix passage.
groundSpeed	Ground speed.
groundSpeed10	Ground speed in tens.
altitude	Altitude/flight level display.
transitionAltitude	Transition altitude.
scratchPad	Scratchpad text.
directRouting	Direct-to or next-route-fix display.
cadFinalAlt	Controller-assigned final altitude.
cadTempAlt	Controller-assigned temporary altitude. Special values 1 and 2 display as cINS and cVIS.
cadAssignedHeading	Controller-assigned heading.
cadAssignedSpeedMach	Controller-assigned speed (K...) or Mach (M...).
cadAssignedRate	Controller-assigned rate.
cadGroundState	Controller-assigned ground state.
cadClearanceFlag	Clearance flag (CLR).
cadScratchpad	CAD scratchpad mirror.

If a source string is unknown to the runtime, it typically renders blank.

TMA Areas

tmaAreas is an array of polygon definitions used for TMA matching.

Property	Type	Description
id	string	Optional human-readable identifier.
airport	string	v3 single-airport form.
airports	string[]	Alternate multi-airport form.
runways	string[]	Runways this polygon applies to.
poly	{lat,lon}[]	Required polygon points.
center	object	Legacy fallback circle form.

Matching summary:

• the timeline airport comes from destinationAirports[0]
• the first matching area with airport and runway overlap is used
• if no polygon matches, v3 config can fall back to airports.<ICAO>.tmaFallback

Airports

airports maps airport ICAO to airport-specific metadata.

Common airport properties

Property	Type	Description
tmaFallback	object	Optional fallback circle using center plus radiusNm.
runways	object	Runway metadata keyed by runway id, e.g. "04L": {"elevFt": 17}.

tmaFallback

Example:

"tmaFallback": {
  "center": { "lat": 55.64336491, "lon": 12.24763954 },
  "radiusNm": 29
}

runways

Example:

"runways": {
  "04L": { "elevFt": 17 },
  "04R": { "elevFt": 17 }
}

Advanced airport options

These are used by the current runtime and are valid advanced config.

eat_lt_spacing

Airport-specific WTC-aware landing-spacing and Expected LR settings for EAT:LT.

This block is optional. If it is missing, ALB uses complete built-in defaults. Existing configs therefore remain valid, and no config-format version increase was required for this feature.

Example:

"eat_lt_spacing": {
  "unknownCategory": "M",
  "expectedRateWindowMinutes": 30,
  "behindSec": {
    "L": { "L": 30,  "M": 30,  "H": 30,  "J": 30 },
    "M": { "L": 60,  "M": 60,  "H": 60,  "J": 60 },
    "H": { "L": 120, "M": 120, "H": 120, "J": 120 },
    "J": { "L": 180, "M": 180, "H": 180, "J": 180 }
  },
  "inFrontSec": {
    "L": { "L": 120, "M": 120, "H": 120, "J": 120 },
    "M": { "L": 60,  "M": 60,  "H": 60,  "J": 60 },
    "H": { "L": 60,  "M": 60,  "H": 60,  "J": 60 },
    "J": { "L": 60,  "M": 60,  "H": 60,  "J": 60 }
  }
}

Property	Type	Default	Accepted values or range	Description
unknownCategory	string	M	L, M, H, J	Fallback WTC category used when an aircraft WTC is missing, blank, or unrecognized.
expectedRateWindowMinutes	int	30	5-120	Future canonical-PLT window used for the Expected LR forecast.
behindSec	object	built-in matrix	complete L/M/H/J matrix of integer seconds	Minimum spacing behind the leader.
inFrontSec	object	built-in matrix	complete L/M/H/J matrix of integer seconds	Minimum space required in front of the follower.

All matrix values are seconds.

Valid WTC categories are:

• L
• M
• H
• J

Matrix orientation matters:

• behindSec[row leader][column follower]
• inFrontSec[row follower][column leader]

Built-in default matrices:

Default behindSec

Leader \ follower	L	M	H	J
L	30	30	30	30
M	60	60	60	60
H	120	120	120	120
J	180	180	180	180

Default inFrontSec

Follower \ leader	L	M	H	J
L	120	120	120	120
M	60	60	60	60
H	60	60	60	60
J	60	60	60	60

Validation behavior:

• unknownCategory must be a valid WTC category or the airport keeps the built-in default fallback of M
• expectedRateWindowMinutes must be an integer from 5 through 120
• each matrix must be a complete L/M/H/J object-of-objects
• each matrix value must be a finite non-negative integer number of seconds
• malformed or incomplete matrix definitions are rejected as a whole rather than partly applied

Operational notes:

• config overrides are optional
• a complete valid airport matrix can override the built-in defaults
• unknown WTC uses the configured airport fallback category
• Expected LR remains a local read-only forecast based on canonical future PLTs

viafix_track_nm_orange

Maps STAR name to configured track miles for ALB's orange timing model.

Orange timing is ALB's route or STAR-based timing estimate from the via-fix or holding-fix area toward touchdown. The value gives ALB a configured distance basis when it builds the corrected ALB estimate branch (ELT-ALB or ETA:ALB) before terminal or post-via live estimates become the better source.

This is advanced airport tuning. Wrong values can make ELT-ALB, EAT planning, and landing-timeline scheduling too early or too late.

Example:

"viafix_track_nm_orange": {
  "TESPI4C": 84.8,
  "TUDLO4C": 93.0
}

Rules:

• values must be numeric
• values must be greater than 0
• values must be less than 500

How ALB uses these values:

• ALB first tries an exact STAR-name match for the aircraft's assigned or persisted STAR
• if there is no exact STAR match, ALB may fall back by via-fix and use the largest configured orange distance among STARs that map to that same via-fix
• the configured value represents track miles from the via-fix or holding-area side of the arrival toward touchdown

Orange timing model behind ELT-ALB

Before the aircraft is deep into terminal or post-via handling, ALB can build its own landing estimate branch from:

1. the current via-fix timing anchor or EVTO
2. the configured orange distance
3. a descent-speed model that converts track miles into seconds

The generic baseline model splits the orange distance into three buckets:

• final 10 NM
• the preceding 20 NM TMA segment
• any remaining higher-distance segment before that

The baseline bucket assumptions are roughly:

• higher segment: about 250 KIAS near FL100
• TMA segment: about 180 KIAS
• final 10 NM: about 145 KIAS

ALB then converts those IAS assumptions into approximate TAS and time. In the generic fallback model that is roughly:

• 250 KIAS -> about 290 KTAS
• 180 KIAS -> about 185 KTAS
• 145 KIAS -> about 149 KTAS

Aircraft-aware refinement, wind, and clamping

When aircraft performance data is available, ALB can refine the orange timing using the flight plan's descent-speed information instead of only the generic jet baseline.

The current aircraft-aware model generally uses:

• a higher descent speed around the aircraft's filed level
• a lower descent speed around 6000 ft
• a final descent speed around 3000 ft
• wake-category-aware bounds so the final segment does not become unrealistic

When upper-wind data is available, ALB also lets that wind influence the orange timing by adjusting the approximate ground speed along the route.

To avoid an unrealistically optimistic ALB branch, the orange result is also bounded against the live ES branch. In practice that means ELT-ALB is not allowed to run too far ahead of the live EuroScope-based landing estimate.

Practical tuning guidance

• treat viafix_track_nm_orange as airport-specific planning calibration, not as a cosmetic display tweak
• if the value is too short, ELT-ALB and ALB-based landing planning become too early
• if the value is too long, ELT-ALB and ALB-based landing planning become too late
• once the aircraft is terminal or post-via, ALB should stop relying on orange distance timing and follow the live ES branch where appropriate

For a more operational explanation, see ICAO / Airport Setups. For the behavior boundary between ELT-ES and ELT-ALB, see Sequencing Model.

eat_lt_sequence_lock

Airport-specific lock threshold tuning for EAT/LT sequence behavior.

Example:

"eat_lt_sequence_lock": {
  "enabled": true,
  "baseDistanceNm": 115.0,
  "extraDistanceNm": 10.0,
  "extraBufferIasKt": 280.0,
  "extraBufferAltFt": 15000.0
}

Property	Type	Description
enabled	bool	Enables this advanced airport-specific threshold.
baseDistanceNm	number	Base distance used in threshold derivation.
extraDistanceNm	number	Additional buffer distance.
extraBufferIasKt	number	IAS used to estimate the extra buffer conversion to time.
extraBufferAltFt	number	Altitude used with IAS for buffer time estimation.

Common Ignored or Legacy Keys

Unknown keys are ignored by the current loader.

In real configs you may commonly see keys like these:

• timelineSort-off
• glEatCombiDisplay-off
• viaFixColors-safe
• aimingPointFt
• ArrivalScenarios-ssoBackup
• ArrivalScenarios-ssoBackup2

Important:

• only the exact key glEatCombiDisplay is read
• only the exact key timelineSort is read
• only the exact key ArrivalScenarios is read
• viaFixColors-safe and aimingPointFt are not read by the current loader