Apparatus

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sensors Mode-S transponder

A4B228

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N401UP · BOEING 757-200 · operated by UNITED PARCEL SERVICE CO

Hex
A4B228
Octal
51131050
Decimal
10,793,512
Country
US
Tail
N401UP
Type
B752
No current signal · last broadcast 3h ago
Flights observed
225
Distinct callsigns
20
Country
US
Last broadcast
3h ago

Last known position

Most recent position reported by Mode-S A4B228.

Country allocation

The ICAO 24-bit address A4B228 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
UPS1234 - 7 2026-07-09
UPS9821 United Parcel Service 6 2026-05-14
UPS887 United Parcel Service 6 2026-04-21
UPS598 United Parcel Service 6 2026-05-14
UPS5847 United Parcel Service 6 2026-05-14
UPS1233 - 6 2026-07-10
UPS682 United Parcel Service 5 2026-04-28
UPS610 - 5 2026-07-14
UPS1160 United Parcel Service 5 2026-05-29
UPS834 United Parcel Service 4 2026-06-05
UPS805 United Parcel Service 4 2026-05-14
UPS673 United Parcel Service 4 2026-04-24
UPS5806 United Parcel Service 4 2026-05-13
UPS2980 United Parcel Service 4 2026-06-05
UPS1274 - 4 2026-07-07
UPS1154 - 4 2026-07-02
UPS1124 United Parcel Service 4 2026-05-31
UPS1052 - 4 2026-06-18
UPS943 United Parcel Service 3 2026-05-09
UPS896 United Parcel Service 3 2026-04-15

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 UPS610 PHL → ORD Jul 14, 07:30 UTCJul 14, 09:00 UTC1h 30m
2026-07-14 UPS610 PHL → ORD Jul 14, 07:33 UTCJul 14, 09:09 UTC1h 36m
2026-07-10 UPS1233 - Jul 10, 03:05 UTCJul 10, 03:45 UTC40m
2026-07-10 UPS1233 - Jul 10, 00:25 UTCJul 10, 00:40 UTC15m
2026-07-09 UPS1234 - Jul 9, 10:40 UTCJul 9, 11:05 UTC25m
2026-07-09 UPS1234 RIC → ORF Jul 9, 10:37 UTCJul 9, 11:00 UTC23m
2026-07-09 UPS1234 - Jul 9, 07:45 UTCJul 9, 08:20 UTC35m
2026-07-09 UPS9301 - Jul 9, 02:20 UTCJul 9, 03:10 UTC50m
2026-07-07 UPS1274 PHL → RDU Jul 7, 07:25 UTCJul 7, 08:25 UTC1h 0m
2026-07-07 UPS1274 PHL → RDU Jul 7, 07:24 UTCJul 7, 08:20 UTC56m
2026-07-07 UPS1283 - Jul 7, 04:05 UTCJul 7, 04:50 UTC45m
2026-07-07 UPS1283 - Jul 7, 02:45 UTCJul 7, 04:50 UTC2h 5m
2026-07-07 UPS1283 CLT → PHL Jul 7, 02:34 UTCJul 7, 03:46 UTC1h 12m
2026-07-03 UPS1284 - Jul 3, 07:30 UTCJul 3, 08:35 UTC1h 5m
2026-07-03 UPS1284 PHL → CLT Jul 3, 07:31 UTCJul 3, 08:33 UTC1h 2m
2026-07-03 UPS1153 - Jul 3, 02:10 UTCJul 3, 02:55 UTC45m
2026-07-02 UPS1154 - Jul 2, 07:40 UTCJul 2, 08:20 UTC40m
2026-07-02 UPS1154 PHL → PIT Jul 2, 07:38 UTCJul 2, 08:20 UTC42m
2026-07-02 UPS609 ORD → PHL Jul 2, 03:01 UTCJul 2, 04:34 UTC1h 33m
2026-07-02 UPS609 ORD → PHL Jul 2, 03:05 UTCJul 2, 04:35 UTC1h 30m
2026-07-01 UPS610 - Jul 1, 07:35 UTCJul 1, 09:10 UTC1h 35m
2026-07-01 UPS610 PHL → ORD Jul 1, 07:27 UTCJul 1, 09:11 UTC1h 44m
2026-07-01 UPS1153 PIT → PHL Jul 1, 02:07 UTCJul 1, 03:02 UTC55m
2026-06-30 UPS1154 - Jun 30, 07:55 UTCJun 30, 08:35 UTC40m
2026-06-30 UPS1154 PHL → PIT Jun 30, 07:55 UTCJun 30, 08:35 UTC40m
2026-06-26 UPS609 - Jun 26, 03:10 UTCJun 26, 04:30 UTC1h 20m
2026-06-25 UPS610 PSQ → ORD Jun 25, 07:45 UTCJun 25, 09:29 UTC1h 45m
2026-06-25 UPS1233 - Jun 25, 01:54 UTCJun 25, 02:35 UTC40m
2026-06-25 UPS1233 - Jun 25, 00:29 UTCJun 25, 00:44 UTC15m
2026-06-24 UPS1234 - Jun 24, 10:49 UTCJun 24, 11:09 UTC20m
2026-06-24 UPS1234 - Jun 24, 07:50 UTCJun 24, 08:24 UTC35m
2026-06-24 UPS1233 - Jun 24, 03:10 UTCJun 24, 03:50 UTC40m
2026-06-24 UPS1233 - Jun 24, 01:49 UTCJun 24, 02:05 UTC15m
2026-06-23 UPS1234 - Jun 23, 10:15 UTCJun 23, 10:35 UTC20m
2026-06-23 UPS1234 - Jun 23, 07:45 UTCJun 23, 08:20 UTC35m
2026-06-23 UPS1131 - Jun 23, 03:34 UTCJun 23, 04:25 UTC50m
2026-06-23 UPS1131 - Jun 23, 01:59 UTCJun 23, 02:24 UTC25m
2026-06-23 UPS9713 - Jun 23, 00:04 UTCJun 23, 00:45 UTC40m
2026-06-18 UPS9733 - Jun 18, 12:10 UTCJun 18, 13:45 UTC1h 35m
2026-06-18 UPS1052 - Jun 18, 10:30 UTCJun 18, 11:05 UTC35m
2026-06-18 UPS1052 MHT → BGR Jun 18, 10:22 UTCJun 18, 11:05 UTC43m
2026-06-18 UPS1052 - Jun 18, 06:20 UTCJun 18, 07:55 UTC1h 35m
2026-06-18 UPS1052 SDF → MHT Jun 18, 06:21 UTCJun 18, 07:55 UTC1h 34m
2026-06-18 UPS1333 - Jun 18, 01:05 UTCJun 18, 03:10 UTC2h 5m
2026-06-18 UPS1333 PBI → SDF Jun 18, 01:07 UTCJun 18, 02:58 UTC1h 51m
2026-06-17 UPS1328 PHL → MCO Jun 17, 07:20 UTCJun 17, 09:35 UTC2h 15m
2026-06-17 UPS1328 PHL → MCO Jun 17, 07:24 UTCJun 17, 09:39 UTC2h 15m
2026-06-17 UPS1351 - Jun 17, 01:50 UTCJun 17, 03:45 UTC1h 55m
2026-06-17 UPS1351 TPA → PHL Jun 17, 01:45 UTCJun 17, 03:44 UTC1h 59m
2026-06-16 UPS5358 DFW → TPA Jun 16, 20:30 UTCJun 16, 22:30 UTC2h 0m

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 N401UP page for operator, model, and routing details .

Mode-S A4B228 frequently asked

What is Mode-S code A4B228?
A4B228 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N401UP.
Where is Mode-S A4B228 registered?
Mode-S code A4B228 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 A4B228 broadcasting right now?
No active broadcast right now. Last signal was 3h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4B228, octal 51131050, decimal 10,793,512.
What flights does A4B228 operate?
Mode-S A4B228 has broadcast 20 distinct callsigns, including UPS1234, UPS9821, UPS887, UPS598, UPS5847.