Apparatus

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sensors Mode-S transponder

40773B

ICAO 24-bit transponder address · allocated to United Kingdom

Currently assigned to G-TUMK · BOEING 737 MAX 8

Hex
40773B
Octal
20073473
Decimal
4,224,827
Country
GB
Tail
G-TUMK
Type
B38M
Broadcasting now · callsign TOM28Y · 5,850 ft
Flights observed
286
Distinct callsigns
20
Country
GB
Last broadcast
3h ago

Current position

40773B is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 40773B falls within the block assigned to United Kingdom (GB) by ICAO Annex 10, Volume III. Every aircraft registered in United Kingdom receives a permanent address from this block at the time of registration; the address stays with the airframe even if the aircraft is re-registered to a different operator within the country.

Callsign history 20 distinct

Callsign Airline Flights Last seen
TFL1579 - 7 2026-07-05
TOM55H TUI Airways 5 2026-05-25
TOM99C - 3 2026-06-30
TOM7DH - 3 2026-04-16
TOM788 - 3 2026-04-14
TOM557 - 3 2026-04-15
TOM556 - 3 2026-04-15
TOM553 - 3 2026-06-25
TOM3EA TUI Airways 3 2026-06-30
TOM2XC TUI Airways 3 2026-04-17
TOM2VK TUI Airways 3 2026-05-25
TOM2PY TUI Airways 3 2026-04-21
TOM1EA - 3 2026-04-17
TOM84B TUI Airways 2 2026-06-20
TOM7PM - 2 2026-04-13
TOM7KJ TUI Airways 2 2026-06-09
TOM6PN TUI Airways 2 2026-05-10
TOM624 - 2 2026-07-10
TOM610 - 2 2026-07-11
TOM5YB TUI Airways 2 2026-04-18

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 TOM627 - Jul 14, 21:50 UTCJul 15, 01:40 UTC3h 49m
2026-07-14 TOM626 LGW → DLM Jul 14, 17:05 UTCJul 14, 20:20 UTC3h 15m
2026-07-14 TOM2EV - Jul 14, 11:15 UTCJul 14, 14:30 UTC3h 15m
2026-07-14 TOM51D - Jul 14, 07:05 UTCJul 14, 09:45 UTC2h 40m
2026-07-13 TOM771 - Jul 13, 19:10 UTCJul 14, 00:10 UTC5h 0m
2026-07-13 TOM770 LGW → HRG Jul 13, 12:35 UTCJul 13, 16:40 UTC4h 5m
2026-07-13 TOM43Y - Jul 13, 08:40 UTCJul 13, 10:50 UTC2h 10m
2026-07-13 TOM1LY LGW → MAH Jul 13, 05:25 UTCJul 13, 07:30 UTC2h 5m
2026-07-12 TOM1BY KGS → LGW Jul 12, 21:45 UTCJul 13, 01:25 UTC3h 40m
2026-07-12 TOM7BT BVC → BHX Jul 12, 16:50 UTCJul 12, 20:15 UTC3h 25m
2026-07-12 TOM47A MAN → SKG Jul 12, 11:30 UTCJul 12, 15:15 UTC3h 45m
2026-07-12 TOM81H - Jul 12, 06:15 UTCJul 12, 09:25 UTC3h 10m
2026-07-12 - - Jul 12, 05:20 UTCJul 12, 05:30 UTC10m
2026-07-11 TOM610 LGW → LGW Jul 11, 08:20 UTCJul 11, 20:20 UTC12h 0m
2026-07-10 TOM624 LGW → LGW Jul 10, 08:00 UTCJul 10, 20:00 UTC12h 0m
2026-07-10 TOM940P CWL → LGW Jul 10, 05:30 UTCJul 10, 06:10 UTC40m
2026-07-09 TOM2PJ - Jul 9, 22:15 UTCJul 10, 02:05 UTC3h 50m
2026-07-09 TOM4BC - Jul 9, 17:05 UTCJul 9, 20:30 UTC3h 25m
2026-07-09 TFL091P - Jul 9, 14:25 UTCJul 9, 15:20 UTC55m
2026-07-09 TFL3LD - Jul 9, 10:05 UTCJul 9, 12:45 UTC2h 40m
2026-07-09 TFL6GE - Jul 9, 06:15 UTCJul 9, 08:15 UTC2h 0m
2026-07-08 TFL8VM - Jul 8, 17:05 UTCJul 8, 20:35 UTC3h 30m
2026-07-08 TFL6DY - Jul 8, 12:35 UTCJul 8, 15:30 UTC2h 55m
2026-07-07 TFL97M - Jul 7, 21:00 UTCJul 8, 00:50 UTC3h 50m
2026-07-07 TFL7VN - Jul 7, 15:20 UTCJul 7, 19:20 UTC4h 0m
2026-07-07 TFL7XC - Jul 7, 09:20 UTCJul 7, 11:45 UTC2h 25m
2026-07-07 TFL8WM - Jul 7, 05:35 UTCJul 7, 07:25 UTC1h 50m
2026-07-06 TFL58L - Jul 6, 20:30 UTCJul 7, 00:25 UTC3h 55m
2026-07-06 TFL92N - Jul 6, 16:00 UTCJul 6, 19:20 UTC3h 20m
2026-07-06 TFL2NB - Jul 6, 10:40 UTCJul 6, 14:10 UTC3h 30m
2026-07-06 TFL5TX - Jul 6, 05:50 UTCJul 6, 08:55 UTC3h 5m
2026-07-06 - - Jul 6, 00:50 UTCJul 6, 01:00 UTC10m
2026-07-05 TFL1579 - Jul 5, 16:20 UTCJul 5, 20:10 UTC3h 50m
2026-07-05 TFL1579 - Jul 5, 15:00 UTCJul 5, 15:10 UTC10m
2026-07-05 TFL1579 - Jul 5, 09:50 UTCJul 5, 13:50 UTC4h 0m
2026-07-04 TFL9MC AYT → AMS Jul 4, 10:20 UTCJul 4, 14:25 UTC4h 5m
2026-07-04 TFL7NB - Jul 4, 05:40 UTCJul 4, 08:50 UTC3h 10m
2026-07-03 TFL7LX ZTH → AMS Jul 3, 10:25 UTCJul 3, 13:40 UTC3h 15m
2026-07-03 TFL1PD - Jul 3, 06:15 UTCJul 3, 08:55 UTC2h 40m
2026-07-02 TFL1579 - Jul 2, 17:00 UTCJul 2, 19:55 UTC2h 55m
2026-07-02 TFL1579 - Jul 2, 16:05 UTCJul 2, 16:20 UTC15m
2026-07-02 TFL1579 - Jul 2, 14:45 UTCJul 2, 14:55 UTC10m
2026-07-02 TFL1579 - Jul 2, 09:45 UTCJul 2, 13:40 UTC3h 55m
2026-07-01 TFL63A DLM → AMS Jul 1, 11:10 UTCJul 1, 14:25 UTC3h 15m
2026-07-01 TFL2KC AMS → DLM Jul 1, 06:15 UTCJul 1, 09:25 UTC3h 10m
2026-06-30 TFL097P - Jun 30, 15:45 UTCJun 30, 16:30 UTC45m
2026-06-30 TOM3EA NBE → NCL Jun 30, 10:45 UTCJun 30, 13:30 UTC2h 45m
2026-06-30 TOM99C - Jun 30, 06:30 UTCJun 30, 09:05 UTC2h 35m
2026-06-29 TOM863 DLM → LGW Jun 29, 14:39 UTCJun 29, 18:19 UTC3h 40m
2026-06-29 TOM1XE - Jun 29, 08:50 UTCJun 29, 12:20 UTC3h 30m

About Mode-S

A Mode-S transponder code (also called an "ICAO 24-bit address" or "hex code") is a 6-character hexadecimal identifier permanently assigned to an aircraft when it's first registered. Unlike callsigns (which change with each flight) or registrations (which can change if an aircraft is sold internationally), the Mode-S address stays with the airframe for the life of the aircraft in that country.

Every ADS-B transmission from an aircraft includes its Mode-S address, making it the most reliable way to identify a specific airframe. Flight-tracking services like Apparatus use the Mode-S address as the primary key for tying position broadcasts, callsigns, and ownership records together.

Prefer a tail-number view? See the G-TUMK page for operator, model, and routing details .

Mode-S 40773B frequently asked

What is Mode-S code 40773B?
40773B is an ICAO 24-bit transponder address. Allocated to United Kingdom. Assigned to G-TUMK.
Where is Mode-S 40773B registered?
Mode-S code 40773B is allocated to United Kingdom (GB). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 40773B broadcasting right now?
Yes. Mode-S 40773B is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 40773B, octal 20073473, decimal 4,224,827.
What flights does 40773B operate?
Mode-S 40773B has broadcast 20 distinct callsigns, including TFL1579, TOM55H, TOM99C, TOM7DH, TOM788.