Apparatus

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sensors Mode-S transponder

A721A4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N559JB · AIRBUS A-320 · operated by UMB BANK NA TRUSTEE

Hex
A721A4
Octal
51620644
Decimal
10,953,124
Country
US
Tail
N559JB
Type
A320
No current signal · last broadcast Jul 26, 21:10 UTC
Flights observed
319
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:10 UTC

Last known position

Most recent position reported by Mode-S A721A4.

Country allocation

The ICAO 24-bit address A721A4 falls within the block assigned to United States (US) by ICAO Annex 10, Volume III. Every aircraft registered in United States 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
JBU154 JetBlue Airways 6 2026-06-12
JBU929 JetBlue Airways 5 2026-05-29
JBU768 JetBlue Airways 4 2026-06-01
JBU438 - 4 2026-06-26
JBU2276 JetBlue Airways 4 2026-06-04
JBU1145 JetBlue Airways 4 2026-06-22
JBU706 - 3 2026-07-08
JBU651 - 3 2026-07-04
JBU634 JetBlue Airways 3 2026-07-25
JBU435 JetBlue Airways 3 2026-07-21
JBU2404 JetBlue Airways 3 2026-04-15
JBU1168 - 3 2026-07-09
JBU1153 JetBlue Airways 3 2026-04-25
JBU1072 JetBlue Airways 3 2026-05-07
JBU98 JetBlue Airways 2 2026-05-19
JBU959 JetBlue Airways 2 2026-04-18
JBU928 JetBlue Airways 2 2026-05-29
JBU927 JetBlue Airways 2 2026-06-10
JBU884 JetBlue Airways 2 2026-04-16
JBU88 JetBlue Airways 2 2026-06-12

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 JBU1797 ATL → FLL Jul 26, 11:08 UTCJul 26, 21:10 UTC10h 3m
2026-07-26 JBU1797 ATL → FLL Jul 26, 11:10 UTCJul 26, 12:35 UTC1h 25m
2026-07-26 JBU719 BOS → SAN Jul 26, 02:15 UTCJul 26, 04:00 UTC1h 45m
2026-07-25 JBU237 BDL → MCO Jul 25, 14:30 UTCJul 25, 22:55 UTC8h 25m
2026-07-25 JBU2001 BUF → JFK Jul 25, 10:45 UTCJul 25, 11:35 UTC50m
2026-07-25 JBU634 SFO → BOS Jul 25, 01:25 UTCJul 25, 02:50 UTC1h 25m
2026-07-24 JBU634 SFO → BOS Jul 24, 22:55 UTCJul 24, 23:15 UTC20m
2026-07-24 JBU703 BDL → RSW Jul 24, 19:10 UTCJul 24, 19:35 UTC25m
2026-07-23 JBU978 LAS → BOS Jul 23, 23:20 UTCJul 24, 19:35 UTC20h 15m
2026-07-23 JBU1148 SAV → BOS Jul 23, 19:58 UTCJul 24, 17:00 UTC21h 2m
2026-07-23 JBU749 FLL → SDQ Jul 23, 16:50 UTCJul 23, 17:00 UTC10m
2026-07-23 JBU749 FLL → SDQ Jul 23, 16:48 UTCJul 24, 12:25 UTC19h 37m
2026-07-23 JBU2380 - Jul 23, 12:45 UTCJul 23, 15:20 UTC2h 35m
2026-07-23 JBU2380 IAH → FLL Jul 23, 12:44 UTCJul 24, 11:00 UTC22h 16m
2026-07-23 JBU2779 FLL → IAH Jul 23, 02:50 UTCJul 23, 04:40 UTC1h 50m
2026-07-23 JBU2779 FLL → IAH Jul 23, 02:25 UTCJul 23, 02:45 UTC20m
2026-07-22 JBU864 ORD → FLL Jul 22, 19:55 UTCJul 22, 22:15 UTC2h 20m
2026-07-22 JBU663 FLL → ORD Jul 22, 15:10 UTCJul 22, 18:00 UTC2h 50m
2026-07-21 JBU435 BOS → DCA Jul 21, 21:55 UTCJul 21, 22:20 UTC25m
2026-07-21 JBU435 BOS → DCA Jul 21, 21:52 UTCJul 22, 21:00 UTC23h 8m
2026-07-21 JBU936 SJU → STT Jul 21, 20:35 UTCJul 21, 20:45 UTC10m
2026-07-21 JBU1638 SDQ → SJU Jul 21, 18:45 UTCJul 21, 18:55 UTC10m
2026-07-21 JBU2537 SJU → SDQ Jul 21, 16:00 UTCJul 21, 16:15 UTC15m
2026-07-21 JBU1233 - Jul 21, 13:45 UTCJul 21, 13:55 UTC10m
2026-07-21 JBU1233 - Jul 21, 11:25 UTCJul 21, 12:05 UTC40m
2026-07-20 JBU1537 JFK → STI Jul 20, 22:05 UTCJul 21, 00:25 UTC2h 20m
2026-07-20 JBU1578 JAX → JFK Jul 20, 17:35 UTCJul 20, 19:55 UTC2h 20m
2026-07-20 JBU2098 - Jul 20, 00:25 UTCJul 20, 01:45 UTC1h 20m
2026-07-20 JBU2098 FLL → ATL Jul 20, 00:25 UTCJul 20, 23:00 UTC22h 36m
2026-07-19 JBU1676 KIN → FLL Jul 19, 21:30 UTCJul 19, 22:10 UTC40m
2026-07-19 JBU1775 - Jul 19, 01:10 UTCJul 19, 01:40 UTC30m
2026-07-19 JBU1775 FLL → KIN Jul 19, 01:10 UTCJul 20, 01:00 UTC23h 51m
2026-07-18 JBU590 SDQ → FLL Jul 18, 17:50 UTCJul 18, 23:05 UTC5h 15m
2026-07-18 JBU1948 FLL → MCO Jul 18, 01:59 UTCJul 18, 23:05 UTC21h 7m
2026-07-17 JBU173 - Jul 17, 17:20 UTCJul 17, 18:44 UTC1h 25m
2026-07-17 JBU173 FLL → PUJ Jul 17, 17:18 UTCJul 18, 15:40 UTC22h 23m
2026-07-17 JBU669 - Jul 17, 12:50 UTCJul 17, 15:25 UTC2h 35m
2026-07-16 JBU68 CHS → BOS Jul 16, 17:07 UTCJul 17, 15:25 UTC22h 18m
2026-07-16 JBU267 BOS → CHS Jul 16, 14:03 UTCJul 17, 13:00 UTC22h 57m
2026-07-15 JBU435 STT → SJU Jul 15, 19:35 UTCJul 16, 18:59 UTC23h 25m
2026-07-15 JBU251 BOS → MCO Jul 15, 05:50 UTCJul 16, 02:45 UTC20h 55m
2026-07-14 JBU1118 JFK → BOS Jul 14, 17:45 UTCJul 14, 18:35 UTC50m
2026-07-14 JBU1118 JFK → BOS Jul 14, 17:45 UTCJul 15, 17:00 UTC23h 15m
2026-07-13 JBU1129 - Jul 13, 10:05 UTCJul 13, 10:35 UTC30m
2026-07-13 JBU1129 PVD → JFK Jul 13, 10:02 UTCJul 14, 04:25 UTC18h 24m
2026-07-12 JBU1196 - Jul 12, 23:25 UTCJul 13, 02:01 UTC2h 35m
2026-07-12 JBU2925 - Jul 12, 18:55 UTCJul 12, 20:30 UTC1h 35m
2026-07-12 JBU2926 - Jul 12, 15:25 UTCJul 12, 17:01 UTC1h 35m
2026-07-12 JBU1754 - Jul 12, 11:10 UTCJul 12, 13:20 UTC2h 10m
2026-07-12 JBU2389 EWR → SJU Jul 12, 02:55 UTCJul 12, 06:15 UTC3h 20m

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 N559JB page for operator, model, and routing details .

Mode-S A721A4 frequently asked

What is Mode-S code A721A4?
A721A4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N559JB.
Where is Mode-S A721A4 registered?
Mode-S code A721A4 is allocated to United States (US). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is A721A4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:10 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A721A4, octal 51620644, decimal 10,953,124.
What flights does A721A4 operate?
Mode-S A721A4 has broadcast 20 distinct callsigns, including JBU154, JBU929, JBU768, JBU438, JBU2276.