Apparatus

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sensors Mode-S transponder

A81BC4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N621UP · BOEING 747-8 · operated by UNITED PARCEL SERVICE CO

Hex
A81BC4
Octal
52015704
Decimal
11,017,156
Country
US
Tail
N621UP
Type
B748
Broadcasting now · callsign UPS10 · 35,000 ft
Flights observed
192
Distinct callsigns
20
Country
US
Last broadcast
1d ago

Current position

A81BC4 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A81BC4 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
UPS61 - 15 2026-06-25
UPS64 United Parcel Service 11 2026-07-08
UPS67 United Parcel Service 10 2026-04-15
UPS62 - 10 2026-06-23
UPS109 United Parcel Service 10 2026-06-26
UPS71 United Parcel Service 9 2026-04-24
UPS203 United Parcel Service 8 2026-06-02
UPS108 - 7 2026-06-25
UPS99 - 6 2026-06-30
UPS63 - 6 2026-07-08
UPS204 - 6 2026-07-04
UPS93 United Parcel Service 5 2026-06-04
UPS81 United Parcel Service 5 2026-05-01
UPS14 United Parcel Service 5 2026-06-03
UPS28 United Parcel Service 4 2026-06-12
UPS213 - 4 2026-07-10
UPS15 - 4 2026-07-03
UPS94 United Parcel Service 3 2026-04-23
UPS72 - 3 2026-07-02
UPS5967 United Parcel Service 3 2026-04-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-12 UPS29 - Jul 12, 18:01 UTCJul 13, 02:30 UTC8h 30m
2026-07-12 UPS29 - Jul 12, 16:35 UTCJul 12, 16:50 UTC15m
2026-07-12 UPS16 - Jul 12, 04:10 UTCJul 12, 13:15 UTC9h 5m
2026-07-11 UPS221 - Jul 11, 17:30 UTCJul 12, 01:05 UTC7h 35m
2026-07-10 UPS214 CGN → SDF Jul 10, 23:30 UTCJul 11, 07:55 UTC8h 25m
2026-07-10 UPS213 - Jul 10, 09:40 UTCJul 10, 11:55 UTC2h 15m
2026-07-10 UPS213 SDF → CGN Jul 10, 09:28 UTCJul 10, 17:09 UTC7h 41m
2026-07-09 UPS2567 MSP → SDF Jul 9, 13:08 UTCJul 9, 14:25 UTC1h 17m
2026-07-09 UPS2567 - Jul 9, 13:10 UTCJul 9, 14:25 UTC1h 15m
2026-07-09 UPS560 - Jul 9, 09:30 UTCJul 9, 10:50 UTC1h 20m
2026-07-09 UPS560 SDF → MSP Jul 9, 09:20 UTCJul 9, 10:53 UTC1h 33m
2026-07-08 UPS63 ANC → SDF Jul 8, 23:40 UTCJul 9, 05:15 UTC5h 35m
2026-07-08 UPS63 HKG → ANC Jul 8, 11:40 UTCJul 8, 21:30 UTC9h 50m
2026-07-08 UPS64 SDF → ANC Jul 8, 08:10 UTCJul 8, 08:30 UTC20m
2026-07-08 UPS64 SDF → ANC Jul 8, 04:50 UTCJul 8, 07:30 UTC2h 40m
2026-07-07 UPS64 SDF → ANC Jul 7, 17:50 UTCJul 8, 01:40 UTC7h 50m
2026-07-07 UPS64 SDF → ANC Jul 7, 07:50 UTCJul 7, 14:00 UTC6h 10m
2026-07-07 UPS64 SDF → ANC Jul 7, 07:46 UTCJul 7, 13:58 UTC6h 12m
2026-07-04 UPS204 - Jul 4, 05:00 UTCJul 4, 07:00 UTC2h 0m
2026-07-04 UPS204 CGN → SDF Jul 4, 05:01 UTCJul 4, 13:41 UTC8h 40m
2026-07-04 UPS204 CGN → SDF Jul 4, 05:01 UTCJul 4, 13:41 UTC8h 40m
2026-07-03 UPS15 DEL → CGN Jul 3, 11:00 UTCJul 3, 19:15 UTC8h 15m
2026-07-02 UPS15 - Jul 2, 23:50 UTCJul 3, 02:30 UTC2h 40m
2026-07-02 UPS74 ONT → SDF Jul 2, 17:50 UTCJul 2, 18:05 UTC15m
2026-07-02 UPS74 ONT → SDF Jul 2, 16:45 UTCJul 2, 17:10 UTC25m
2026-07-02 UPS72 - Jul 2, 02:15 UTCJul 2, 13:35 UTC11h 20m
2026-07-01 UPS72 SDF → ANC Jul 1, 17:44 UTCJul 1, 23:36 UTC5h 52m
2026-07-01 UPS72 - Jul 1, 17:45 UTCJul 1, 23:40 UTC5h 55m
2026-06-30 UPS99 ANC → SDF Jun 30, 23:01 UTCJul 1, 04:41 UTC5h 40m
2026-06-30 UPS99 ANC → SDF Jun 30, 22:55 UTCJul 1, 04:45 UTC5h 50m
2026-06-30 UPS99 - Jun 30, 13:00 UTCJun 30, 20:15 UTC7h 15m
2026-06-30 UPS99 ICN → ANC Jun 30, 12:58 UTCJun 30, 20:13 UTC7h 15m
2026-06-30 UPS173 - Jun 30, 10:15 UTCJun 30, 10:35 UTC20m
2026-06-30 UPS174 - Jun 30, 04:00 UTCJun 30, 04:15 UTC15m
2026-06-29 UPS35 - Jun 29, 06:54 UTCJun 29, 07:15 UTC20m
2026-06-29 UPS35 HNL → ICN Jun 29, 07:01 UTCJun 29, 16:18 UTC9h 17m
2026-06-28 UPS6032 - Jun 28, 20:19 UTCJun 29, 05:00 UTC8h 40m
2026-06-28 UPS6032 SDF → HNL Jun 28, 19:48 UTCJun 29, 05:00 UTC9h 12m
2026-06-26 UPS109 NRT → SDF Jun 26, 23:19 UTCJun 27, 05:04 UTC5h 45m
2026-06-26 UPS109 NRT → SDF Jun 26, 13:59 UTCJun 26, 20:10 UTC6h 10m
2026-06-26 UPS109 NRT → SDF Jun 26, 01:24 UTCJun 26, 11:20 UTC9h 55m
2026-06-25 UPS108 - Jun 25, 09:25 UTCJun 25, 21:59 UTC12h 35m
2026-06-25 UPS61 ANC → SDF Jun 25, 00:40 UTCJun 25, 06:20 UTC5h 40m
2026-06-24 UPS61 - Jun 24, 14:20 UTCJun 24, 21:14 UTC6h 55m
2026-06-24 UPS61 - Jun 24, 12:34 UTCJun 24, 12:50 UTC15m
2026-06-24 UPS61 - Jun 24, 09:15 UTCJun 24, 09:45 UTC30m
2026-06-24 UPS61 - Jun 24, 08:24 UTCJun 24, 08:39 UTC15m
2026-06-23 UPS62 - Jun 23, 18:20 UTCJun 24, 04:20 UTC10h 0m
2026-06-23 UPS62 - Jun 23, 08:20 UTCJun 23, 14:15 UTC5h 55m
2026-06-22 UPS109 NRT → SDF Jun 22, 23:05 UTCJun 23, 04:50 UTC5h 45m

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 N621UP page for operator, model, and routing details .

Mode-S A81BC4 frequently asked

What is Mode-S code A81BC4?
A81BC4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N621UP.
Where is Mode-S A81BC4 registered?
Mode-S code A81BC4 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 A81BC4 broadcasting right now?
Yes. Mode-S A81BC4 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A81BC4, octal 52015704, decimal 11,017,156.
What flights does A81BC4 operate?
Mode-S A81BC4 has broadcast 20 distinct callsigns, including UPS61, UPS64, UPS67, UPS62, UPS109.