Apparatus

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sensors Mode-S transponder

400FF4

ICAO 24-bit transponder address · allocated to United Kingdom

Currently assigned to G-FDZD · BOEING 737-800

Hex
400FF4
Octal
20007764
Decimal
4,198,388
Country
GB
Tail
G-FDZD
Type
B738
No current signal · last broadcast Jul 26, 23:00 UTC
Flights observed
345
Distinct callsigns
20
Country
GB
Last broadcast
Jul 26, 23:00 UTC

Last known position

Most recent position reported by Mode-S 400FF4.

Country allocation

The ICAO 24-bit address 400FF4 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
TOM8KE TUI Airways 5 2026-07-04
TOM23G - 5 2026-07-04
TOM213 - 5 2026-07-11
TOM9TM - 4 2026-07-11
TOM86L TUI Airways 4 2026-07-07
TOM7WJ TUI Airways 4 2026-07-04
TOM7LN - 4 2026-07-11
TOM5XY - 4 2026-07-11
TOM5JK - 4 2026-06-30
TOM3WN - 4 2026-07-10
TOM2BA TUI Airways 4 2026-07-04
TOM9KY TUI Airways 3 2026-07-07
TOM9KN - 3 2026-07-10
TOM9BJ - 3 2026-04-13
TOM8VA TUI Airways 3 2026-07-07
TOM8EV TUI Airways 3 2026-07-22
TOM7XY TUI Airways 3 2026-06-08
TOM7AN TUI Airways 3 2026-06-08
TOM6NK - 3 2026-07-05
TOM64C TUI Airways 3 2026-07-22

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 TOM8WK BHX → PFO Jul 26, 13:00 UTCJul 26, 23:00 UTC10h 0m
2026-07-26 TOM5JL KGS → CWL Jul 26, 09:25 UTCJul 26, 11:40 UTC2h 15m
2026-07-26 TOM28K ALC → EMA Jul 26, 06:00 UTCJul 26, 08:00 UTC2h 1m
2026-07-25 TOM1YL BRS → HRG Jul 25, 12:40 UTCJul 25, 15:55 UTC3h 15m
2026-07-24 TOM3PD MLA → BHX Jul 24, 17:05 UTCJul 24, 18:45 UTC1h 40m
2026-07-24 TOM3PD MLA → BHX Jul 24, 16:00 UTCJul 24, 17:00 UTC1h 0m
2026-07-24 TOM2YB - Jul 24, 11:15 UTCJul 24, 14:15 UTC3h 0m
2026-07-24 TOM3NX BRS → DLM Jul 24, 07:00 UTCJul 24, 09:15 UTC2h 15m
2026-07-23 TOM9VB ACE → CWL Jul 23, 20:35 UTCJul 23, 22:40 UTC2h 5m
2026-07-23 TOM7YN DSA → KGS Jul 23, 17:20 UTCJul 23, 19:30 UTC2h 10m
2026-07-23 TOM7NT VRN → DUB Jul 23, 11:35 UTCJul 23, 15:25 UTC3h 50m
2026-07-23 TOM3CL LCA → NCL Jul 23, 06:50 UTCJul 23, 10:00 UTC3h 10m
2026-07-22 TOM19V AGP → MAN Jul 22, 22:25 UTCJul 23, 00:30 UTC2h 5m
2026-07-22 TOM8EV RVN → NCL Jul 22, 19:10 UTCJul 22, 21:15 UTC2h 5m
2026-07-22 TOM64C MAH → NWI Jul 22, 12:15 UTCJul 22, 16:50 UTC4h 35m
2026-07-21 TOM623 NBE → STN Jul 21, 20:40 UTCJul 21, 23:15 UTC2h 35m
2026-07-21 TOM622 STN → NBE Jul 21, 16:40 UTCJul 21, 19:05 UTC2h 25m
2026-07-21 TOM79D MLA → MLA Jul 21, 11:30 UTCJul 21, 14:45 UTC3h 15m
2026-07-21 TOM2PE STN → ZTH Jul 21, 07:20 UTCJul 21, 10:10 UTC2h 50m
2026-07-20 TOM7LH CFU → STN Jul 20, 18:45 UTCJul 20, 22:25 UTC3h 40m
2026-07-20 TOM8HJ DBV → GLA Jul 20, 13:55 UTCJul 20, 17:15 UTC3h 20m
2026-07-20 TOM82K CFU → BHX Jul 20, 08:45 UTCJul 20, 10:55 UTC2h 10m
2026-07-20 TOM3VN - Jul 20, 05:30 UTCJul 20, 07:30 UTC2h 0m
2026-07-19 TOM4AX RAK → LGW Jul 19, 22:05 UTCJul 20, 01:40 UTC3h 35m
2026-07-19 TOM1AN LGW → AGP Jul 19, 16:30 UTCJul 19, 19:40 UTC3h 10m
2026-07-19 TOM73E EFL → STN Jul 19, 11:45 UTCJul 19, 14:55 UTC3h 10m
2026-07-19 TOM3DE BRS → BOH Jul 19, 07:45 UTCJul 19, 10:35 UTC2h 50m
2026-07-18 TOM63A BRS → BRS Jul 18, 20:15 UTCJul 19, 00:30 UTC4h 15m
2026-07-18 TOM80E JSI → EMA Jul 18, 15:10 UTCJul 18, 18:35 UTC3h 25m
2026-07-18 TOM3FX PMI → NCL Jul 18, 11:20 UTCJul 18, 13:20 UTC2h 0m
2026-07-18 TOM51X MAN → AYT Jul 18, 07:30 UTCJul 18, 09:35 UTC2h 5m
2026-07-17 TOM661 NBE → STN Jul 17, 22:10 UTCJul 18, 00:25 UTC2h 15m
2026-07-17 TOM660 STN → NBE Jul 17, 18:19 UTCJul 17, 20:40 UTC2h 20m
2026-07-17 TOM2YB - Jul 17, 13:29 UTCJul 17, 16:34 UTC3h 5m
2026-07-17 TOM3NX BRS → DLM Jul 17, 07:14 UTCJul 17, 09:35 UTC2h 20m
2026-07-16 TOM9VB ACE → CWL Jul 16, 20:45 UTCJul 16, 22:45 UTC2h 0m
2026-07-16 TOM7YN - Jul 16, 17:35 UTCJul 16, 19:30 UTC1h 55m
2026-07-16 TOM7NT - Jul 16, 11:45 UTCJul 16, 15:30 UTC3h 45m
2026-07-16 TOM3CL - Jul 16, 06:40 UTCJul 16, 09:45 UTC3h 5m
2026-07-15 TOM19V IBZ → STN Jul 15, 22:50 UTCJul 16, 00:50 UTC2h 0m
2026-07-15 TOM8EV - Jul 15, 19:40 UTCJul 15, 21:55 UTC2h 15m
2026-07-15 TOM64C - Jul 15, 12:00 UTCJul 15, 16:35 UTC4h 35m
2026-07-15 TOM30K - Jul 15, 06:40 UTCJul 15, 10:25 UTC3h 45m
2026-07-14 TOM1MV - Jul 14, 19:10 UTCJul 14, 22:35 UTC3h 25m
2026-07-14 TOM9PY - Jul 14, 13:15 UTCJul 14, 17:35 UTC4h 20m
2026-07-14 TOM9XH - Jul 14, 09:05 UTCJul 14, 11:00 UTC1h 55m
2026-07-14 TOM8XE - Jul 14, 05:20 UTCJul 14, 07:25 UTC2h 5m
2026-07-13 TOM125 - Jul 13, 19:55 UTCJul 13, 22:50 UTC2h 55m
2026-07-13 TOM124 - Jul 13, 15:40 UTCJul 13, 18:20 UTC2h 40m
2026-07-13 TOM82K MAH → STN Jul 13, 09:10 UTCJul 13, 11:15 UTC2h 5m

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-FDZD page for operator, model, and routing details .

Mode-S 400FF4 frequently asked

What is Mode-S code 400FF4?
400FF4 is an ICAO 24-bit transponder address. Allocated to United Kingdom. Assigned to G-FDZD.
Where is Mode-S 400FF4 registered?
Mode-S code 400FF4 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 400FF4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 23:00 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 400FF4, octal 20007764, decimal 4,198,388.
What flights does 400FF4 operate?
Mode-S 400FF4 has broadcast 20 distinct callsigns, including TOM8KE, TOM23G, TOM213, TOM9TM, TOM86L.