Apparatus

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sensors Mode-S transponder

A445CD

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N37456 · BOEING 737-900 · operated by UNITED AIRLINES INC

Hex
A445CD
Octal
51042715
Decimal
10,765,773
Country
US
Tail
N37456
Type
B739
No current signal · last broadcast Jul 26, 21:15 UTC
Flights observed
445
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:15 UTC

Last known position

Most recent position reported by Mode-S A445CD.

Country allocation

The ICAO 24-bit address A445CD 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
UAL2443 United Airlines 8 2026-07-26
UAL215 United Airlines 7 2026-05-29
UAL2784 - 5 2026-07-19
UAL636 United Airlines 4 2026-05-29
UAL543 - 4 2026-06-24
UAL2627 United Airlines 4 2026-07-09
UAL2466 - 4 2026-06-21
UAL2053 United Airlines 4 2026-07-23
UAL1752 United Airlines 4 2026-05-26
UAL1335 United Airlines 4 2026-06-24
UAL729 - 3 2026-06-18
UAL723 United Airlines 3 2026-04-13
UAL659 - 3 2026-06-17
UAL651 - 3 2026-06-22
UAL638 United Airlines 3 2026-05-10
UAL622 - 3 2026-07-22
UAL379 United Airlines 3 2026-05-09
UAL279 - 3 2026-06-19
UAL2389 United Airlines 3 2026-07-26
UAL1866 - 3 2026-04-15

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL2437 LGA → DEN Jul 26, 21:10 UTCJul 26, 21:15 UTC5m
2026-07-26 UAL2443 MSN → ORD Jul 26, 18:15 UTCJul 26, 19:35 UTC1h 20m
2026-07-26 UAL2389 LGA → ORD Jul 26, 15:55 UTCJul 26, 16:45 UTC50m
2026-07-26 UAL1733 PDX → SFO Jul 26, 11:25 UTCJul 26, 13:35 UTC2h 10m
2026-07-25 UAL2443 MSN → ORD Jul 25, 23:55 UTCJul 26, 01:45 UTC1h 50m
2026-07-25 UAL1196 CUN → ORD Jul 25, 17:30 UTCJul 25, 20:45 UTC3h 15m
2026-07-25 UAL1154 IAD → CUN Jul 25, 12:40 UTCJul 25, 15:40 UTC3h 0m
2026-07-25 UAL357 IAD → SFO Jul 25, 05:05 UTCJul 25, 09:35 UTC4h 30m
2026-07-25 UAL357 IAD → SFO Jul 25, 05:05 UTCJul 25, 09:31 UTC4h 26m
2026-07-25 UAL8180 YUL → LGA Jul 25, 01:55 UTCJul 25, 03:00 UTC1h 5m
2026-07-24 UAL1281 RNO → SFO Jul 24, 22:20 UTCJul 25, 00:10 UTC1h 50m
2026-07-24 UAL1195 DTW → ORD Jul 24, 19:05 UTCJul 24, 20:15 UTC1h 10m
2026-07-24 UAL361 DEN → BOS Jul 24, 16:45 UTCJul 24, 17:45 UTC1h 0m
2026-07-24 UAL1745 SFO → IAH Jul 24, 02:35 UTCJul 24, 04:00 UTC1h 25m
2026-07-23 UAL2053 SFO → PDX Jul 23, 22:10 UTCJul 24, 01:10 UTC3h 0m
2026-07-23 UAL1732 PHL → IAH Jul 23, 16:50 UTCJul 23, 17:15 UTC25m
2026-07-23 UAL1732 PHL → IAH Jul 23, 16:46 UTCJul 23, 18:35 UTC1h 49m
2026-07-23 UAL1076 DEN → SFO Jul 23, 13:00 UTCJul 23, 14:45 UTC1h 45m
2026-07-23 UAL1148 DEN → BOS Jul 23, 07:05 UTCJul 23, 10:30 UTC3h 25m
2026-07-23 UAL1828 ORD → SAT Jul 23, 01:35 UTCJul 23, 05:14 UTC3h 39m
2026-07-23 UAL1828 ORD → SAT Jul 23, 01:20 UTCJul 23, 05:15 UTC3h 55m
2026-07-22 UAL2299 LAS → SFO Jul 22, 21:35 UTCJul 22, 23:25 UTC1h 50m
2026-07-22 UAL2299 LAS → SFO Jul 22, 21:27 UTCJul 22, 23:09 UTC1h 42m
2026-07-22 UAL685 IAH → EWR Jul 22, 17:50 UTCJul 22, 19:40 UTC1h 50m
2026-07-22 UAL685 IAH → EWR Jul 22, 17:49 UTCJul 22, 19:37 UTC1h 48m
2026-07-22 UAL622 - Jul 22, 15:15 UTCJul 22, 16:20 UTC1h 5m
2026-07-22 UAL622 CMH → ORD Jul 22, 15:17 UTCJul 22, 16:04 UTC47m
2026-07-22 UAL2779 FRA → SFO Jul 22, 12:53 UTCJul 22, 13:30 UTC37m
2026-07-22 UAL2779 FRA → SFO Jul 22, 12:45 UTCJul 22, 13:35 UTC50m
2026-07-22 UAL1672 DEN → SFO Jul 22, 02:20 UTCJul 22, 05:15 UTC2h 55m
2026-07-22 UAL1672 DEN → SFO Jul 22, 02:24 UTCJul 22, 05:03 UTC2h 39m
2026-07-21 UAL716 CHS → DEN Jul 21, 23:05 UTCJul 22, 00:25 UTC1h 20m
2026-07-21 UAL414 BOS → DEN Jul 21, 17:45 UTCJul 21, 21:50 UTC4h 5m
2026-07-21 UAL375 EWR → BOS Jul 21, 15:05 UTCJul 21, 15:55 UTC50m
2026-07-21 UAL2673 ORD → LGA Jul 21, 10:40 UTCJul 21, 12:30 UTC1h 50m
2026-07-21 UAL2335 - Jul 21, 02:00 UTCJul 21, 03:45 UTC1h 45m
2026-07-20 UAL1205 - Jul 20, 23:05 UTCJul 21, 00:20 UTC1h 14m
2026-07-20 UAL2091 - Jul 20, 20:15 UTCJul 20, 21:45 UTC1h 30m
2026-07-20 UAL2370 SMF → ORD Jul 20, 14:10 UTCJul 20, 18:00 UTC3h 50m
2026-07-19 UAL1920 ORD → SMF Jul 19, 21:30 UTCJul 20, 01:15 UTC3h 45m
2026-07-19 UAL2784 - Jul 19, 19:25 UTCJul 19, 19:35 UTC10m
2026-07-19 UAL2784 PHL → ORD Jul 19, 17:45 UTCJul 19, 19:35 UTC1h 50m
2026-07-19 UAL2784 PHL → ORD Jul 19, 17:45 UTCJul 19, 19:08 UTC1h 23m
2026-07-19 UAL2752 - Jul 19, 14:35 UTCJul 19, 16:00 UTC1h 25m
2026-07-19 UAL2070 SFO → PDX Jul 19, 10:25 UTCJul 19, 11:55 UTC1h 30m
2026-07-19 UAL1573 SFO → BOS Jul 19, 03:10 UTCJul 19, 07:30 UTC4h 20m
2026-07-19 UAL1573 SFO → BOS Jul 19, 03:10 UTCJul 19, 07:34 UTC4h 24m
2026-07-18 UAL1689 - Jul 18, 21:10 UTCJul 19, 01:50 UTC4h 40m
2026-07-18 UAL2331 TPA → IAD Jul 18, 16:00 UTCJul 18, 17:50 UTC1h 50m
2026-07-12 UAL1140 IAD → TPA Jul 12, 22:45 UTCJul 13, 00:45 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 N37456 page for operator, model, and routing details .

Mode-S A445CD frequently asked

What is Mode-S code A445CD?
A445CD is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N37456.
Where is Mode-S A445CD registered?
Mode-S code A445CD 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 A445CD broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:15 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A445CD, octal 51042715, decimal 10,765,773.
What flights does A445CD operate?
Mode-S A445CD has broadcast 20 distinct callsigns, including UAL2443, UAL215, UAL2784, UAL636, UAL543.