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sensors Mode-S transponder

4A2021

ICAO 24-bit transponder address · allocated to Romania

Currently assigned to YR-HAA · AIRBUS A-320

Hex
4A2021
Octal
22420041
Decimal
4,857,889
Country
RO
Tail
YR-HAA
Type
A320
Broadcasting now · callsign ROT416M · 1,825 ft
Flights observed
274
Distinct callsigns
20
Country
RO
Last broadcast
1h ago

Current position

4A2021 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 4A2021 falls within the block assigned to Romania (RO) by ICAO Annex 10, Volume III. Every aircraft registered in Romania 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
ROT415K Tarom 44 2026-07-21
ROT416M - 43 2026-07-20
HLJ3BF - 15 2026-05-25
ROT648P - 14 2026-07-18
ROT647M - 14 2026-07-18
ROT274K - 13 2026-07-12
ROT273L - 13 2026-07-12
ROT364Q - 8 2026-07-16
ROT363T - 8 2026-07-16
ROT642V Tarom 7 2026-07-20
ROT641X Tarom 7 2026-07-20
ROT608L Tarom 6 2026-07-17
ROT607R Tarom 6 2026-07-17
ROT362Q - 6 2026-07-16
ROT361U - 6 2026-07-16
HLJ1CD - 6 2026-05-27
HLJ4AE - 5 2026-05-27
HLJ4AB - 4 2026-05-22
HLJ2VV - 4 2026-05-01
ROT402D - 3 2026-07-04

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-21 ROT415K OTP → MAD Jul 21, 05:45 UTCJul 21, 09:25 UTC3h 40m
2026-07-20 ROT416M - Jul 20, 13:10 UTCJul 20, 16:10 UTC3h 0m
2026-07-20 ROT415K OTP → MAD Jul 20, 07:45 UTCJul 20, 11:30 UTC3h 45m
2026-07-20 ROT642V CLJ → OTP Jul 20, 05:25 UTCJul 20, 05:55 UTC30m
2026-07-20 ROT641X OTP → CLJ Jul 20, 03:35 UTCJul 20, 04:05 UTC30m
2026-07-19 ROT306J FRA → OTP Jul 19, 20:55 UTCJul 19, 22:40 UTC1h 45m
2026-07-19 ROT305Z OTP → FRA Jul 19, 17:35 UTCJul 19, 19:40 UTC2h 5m
2026-07-19 ROT416M MAD → OTP Jul 19, 11:30 UTCJul 19, 14:25 UTC2h 55m
2026-07-19 ROT415K OTP → MAD Jul 19, 05:40 UTCJul 19, 09:15 UTC3h 35m
2026-07-18 ROT648P - Jul 18, 17:50 UTCJul 18, 18:20 UTC30m
2026-07-18 ROT647M - Jul 18, 16:05 UTCJul 18, 16:35 UTC30m
2026-07-18 ROT416M - Jul 18, 11:35 UTCJul 18, 14:35 UTC3h 0m
2026-07-18 ROT415K - Jul 18, 06:15 UTCJul 18, 09:50 UTC3h 35m
2026-07-17 ROT608L TSR → OTP Jul 17, 17:25 UTCJul 17, 18:00 UTC35m
2026-07-17 ROT607R OTP → TSR Jul 17, 15:49 UTCJul 17, 16:19 UTC30m
2026-07-17 ROT416M - Jul 17, 11:25 UTCJul 17, 14:30 UTC3h 5m
2026-07-17 ROT415K - Jul 17, 05:35 UTCJul 17, 09:10 UTC3h 35m
2026-07-16 ROT364Q - Jul 16, 19:10 UTCJul 16, 21:30 UTC2h 20m
2026-07-16 ROT363T - Jul 16, 14:15 UTCJul 16, 16:55 UTC2h 40m
2026-07-16 ROT362Q - Jul 16, 10:20 UTCJul 16, 12:34 UTC2h 15m
2026-07-16 ROT361U - Jul 16, 06:10 UTCJul 16, 08:45 UTC2h 35m
2026-07-15 ROT648P - Jul 15, 17:10 UTCJul 15, 17:40 UTC30m
2026-07-15 ROT647M - Jul 15, 15:30 UTCJul 15, 16:00 UTC30m
2026-07-15 ROT416M - Jul 15, 10:55 UTCJul 15, 14:00 UTC3h 5m
2026-07-15 ROT415K - Jul 15, 05:35 UTCJul 15, 09:10 UTC3h 35m
2026-07-14 ROT648P - Jul 14, 17:35 UTCJul 14, 18:05 UTC30m
2026-07-14 ROT647M - Jul 14, 15:55 UTCJul 14, 16:25 UTC30m
2026-07-14 ROT416M - Jul 14, 11:30 UTCJul 14, 14:30 UTC3h 0m
2026-07-14 ROT415K - Jul 14, 05:45 UTCJul 14, 09:05 UTC3h 20m
2026-07-13 ROT364Q - Jul 13, 20:50 UTCJul 13, 23:05 UTC2h 15m
2026-07-13 ROT363T - Jul 13, 16:25 UTCJul 13, 19:05 UTC2h 40m
2026-07-13 ROT416M - Jul 13, 12:00 UTCJul 13, 15:00 UTC3h 0m
2026-07-13 ROT415K - Jul 13, 06:50 UTCJul 13, 10:40 UTC3h 50m
2026-07-13 ROT642V - Jul 13, 05:01 UTCJul 13, 05:31 UTC30m
2026-07-13 ROT641X - Jul 13, 03:40 UTCJul 13, 04:00 UTC20m
2026-07-12 ROT274K - Jul 12, 18:25 UTCJul 12, 19:30 UTC1h 5m
2026-07-12 ROT273L - Jul 12, 15:35 UTCJul 12, 17:01 UTC1h 25m
2026-07-12 ROT416M - Jul 12, 11:10 UTCJul 12, 14:15 UTC3h 5m
2026-07-12 ROT415K OTP → MAD Jul 12, 05:45 UTCJul 12, 09:20 UTC3h 35m
2026-07-11 ROT648P - Jul 11, 17:00 UTCJul 11, 17:35 UTC35m
2026-07-11 ROT647M - Jul 11, 15:35 UTCJul 11, 16:05 UTC30m
2026-07-11 ROT416M - Jul 11, 10:45 UTCJul 11, 13:55 UTC3h 10m
2026-07-11 ROT415K - Jul 11, 05:35 UTCJul 11, 09:00 UTC3h 25m
2026-07-10 ROT608L - Jul 10, 17:40 UTCJul 10, 18:15 UTC35m
2026-07-10 ROT607R - Jul 10, 16:00 UTCJul 10, 16:35 UTC35m
2026-07-10 ROT416M - Jul 10, 11:00 UTCJul 10, 14:10 UTC3h 10m
2026-07-10 ROT415K - Jul 10, 05:30 UTCJul 10, 09:05 UTC3h 35m
2026-07-09 ROT364Q - Jul 9, 18:45 UTCJul 9, 21:00 UTC2h 15m
2026-07-09 ROT363T - Jul 9, 14:05 UTCJul 9, 16:55 UTC2h 50m
2026-07-09 ROT362Q - Jul 9, 10:30 UTCJul 9, 12:40 UTC2h 10m

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 YR-HAA page for operator, model, and routing details .

Mode-S 4A2021 frequently asked

What is Mode-S code 4A2021?
4A2021 is an ICAO 24-bit transponder address. Allocated to Romania. Assigned to YR-HAA.
Where is Mode-S 4A2021 registered?
Mode-S code 4A2021 is allocated to Romania (RO). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4A2021 broadcasting right now?
Yes. Mode-S 4A2021 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4A2021, octal 22420041, decimal 4,857,889.
What flights does 4A2021 operate?
Mode-S 4A2021 has broadcast 20 distinct callsigns, including ROT415K, ROT416M, HLJ3BF, ROT648P, ROT647M.