Apparatus

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sensors Mode-S transponder

A449CB

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N37577 · BOEING 737 MAX 9 · operated by UNITED AIRLINES INC

Hex
A449CB
Octal
51044713
Decimal
10,766,795
Country
US
Tail
N37577
Type
B39M
Broadcasting now · callsign UAL1265 · 32,000 ft
Flights observed
450
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:45 UTC

Current position

A449CB is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A449CB 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
UAL1742 United Airlines 6 2026-05-02
UAL639 - 5 2026-07-11
UAL2182 - 5 2026-07-11
UAL1904 United Airlines 5 2026-07-24
UAL797 United Airlines 4 2026-04-18
UAL2667 United Airlines 4 2026-06-11
UAL2636 - 4 2026-06-22
UAL2435 United Airlines 4 2026-04-15
UAL1703 - 4 2026-07-08
UAL1573 United Airlines 4 2026-04-23
UAL1543 United Airlines 4 2026-07-26
UAL1260 - 4 2026-07-15
UAL1249 United Airlines 4 2026-05-31
UAL1170 United Airlines 4 2026-05-04
UAL1118 United Airlines 4 2026-04-17
UAL1034 United Airlines 4 2026-05-30
UAL1021 - 4 2026-07-07
UAL701 - 3 2026-06-16
UAL308 - 3 2026-07-11
UAL293 United Airlines 3 2026-04-22

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL1168 BZN → SFO Jul 26, 19:05 UTCJul 26, 22:45 UTC3h 40m
2026-07-26 UAL2120 MFE → IAH Jul 26, 14:40 UTCJul 26, 16:40 UTC2h 0m
2026-07-26 UAL788 SFO → PSP Jul 26, 10:45 UTCJul 26, 12:50 UTC2h 5m
2026-07-26 UAL2219 SJU → EWR Jul 26, 05:20 UTCJul 26, 09:00 UTC3h 41m
2026-07-26 UAL1543 EWR → SJU Jul 26, 03:40 UTCJul 26, 04:00 UTC20m
2026-07-26 UAL1543 EWR → SJU Jul 26, 01:16 UTCJul 26, 03:57 UTC2h 41m
2026-07-26 UAL1543 EWR → SJU Jul 26, 00:45 UTCJul 26, 01:00 UTC15m
2026-07-25 UAL1574 LAS → SFO Jul 25, 20:20 UTCJul 25, 21:05 UTC45m
2026-07-25 UAL1574 LAS → SFO Jul 25, 18:05 UTCJul 25, 21:05 UTC3h 0m
2026-07-25 UAL1574 LAS → SFO Jul 25, 18:10 UTCJul 25, 20:03 UTC1h 53m
2026-07-25 UAL454 BOS → EWR Jul 25, 13:30 UTCJul 25, 16:25 UTC2h 55m
2026-07-25 UAL404 SFO → DEN Jul 25, 00:25 UTCJul 25, 03:25 UTC3h 0m
2026-07-24 UAL2690 LAS → IAH Jul 24, 19:50 UTCJul 24, 22:50 UTC3h 0m
2026-07-24 UAL1905 LGA → DEN Jul 24, 07:00 UTCJul 24, 11:30 UTC4h 30m
2026-07-24 UAL1904 EWR → SFO Jul 24, 00:10 UTCJul 24, 04:25 UTC4h 15m
2026-07-23 UAL3041 PHL → SFO Jul 23, 01:20 UTCJul 23, 05:25 UTC4h 5m
2026-07-22 UAL1425 EWR → SAL Jul 22, 03:22 UTCJul 22, 08:14 UTC4h 52m
2026-07-22 UAL1425 EWR → SAL Jul 22, 03:55 UTCJul 22, 05:25 UTC1h 30m
2026-07-21 UAL2330 PHX → EWR Jul 21, 12:25 UTCJul 21, 14:50 UTC2h 25m
2026-07-21 UAL1230 YVR → SFO Jul 21, 05:30 UTCJul 21, 10:40 UTC5h 10m
2026-07-20 UAL512 SAN → SFO Jul 20, 20:30 UTCJul 21, 02:05 UTC5h 34m
2026-07-20 UAL1392 IAD → BOS Jul 20, 17:20 UTCJul 20, 18:35 UTC1h 15m
2026-07-20 UAL2066 ORD → PHL Jul 20, 15:15 UTCJul 20, 15:50 UTC35m
2026-07-20 UAL2112 JAX → EWR Jul 20, 12:50 UTCJul 20, 13:25 UTC35m
2026-07-20 UAL8102 YYZ → YQB Jul 20, 04:50 UTCJul 20, 05:35 UTC45m
2026-07-19 UAL1053 CUN → EWR Jul 19, 21:40 UTCJul 20, 01:25 UTC3h 45m
2026-07-19 UAL1177 DEN → CUN Jul 19, 16:01 UTCJul 19, 19:30 UTC3h 29m
2026-07-19 UAL1177 DEN → CUN Jul 19, 16:00 UTCJul 19, 19:35 UTC3h 35m
2026-07-19 UAL1026 DEN → AUS Jul 19, 13:25 UTCJul 19, 14:00 UTC35m
2026-07-19 UAL1092 DEN → MSO Jul 19, 02:53 UTCJul 19, 04:34 UTC1h 41m
2026-07-19 UAL1092 - Jul 19, 03:00 UTCJul 19, 03:40 UTC40m
2026-07-18 UAL1136 CUN → DEN Jul 18, 21:15 UTCJul 19, 00:40 UTC3h 25m
2026-07-18 UAL1167 FLL → EWR Jul 18, 17:50 UTCJul 18, 18:15 UTC25m
2026-07-18 UAL1167 FLL → EWR Jul 18, 17:56 UTCJul 18, 19:30 UTC1h 34m
2026-07-18 UAL2748 - Jul 18, 12:25 UTCJul 18, 16:10 UTC3h 45m
2026-07-18 UAL2820 ORD → SEA Jul 18, 03:15 UTCJul 18, 07:00 UTC3h 45m
2026-07-18 UAL1813 - Jul 18, 00:19 UTCJul 18, 01:10 UTC50m
2026-07-18 UAL1813 CVG → ORD Jul 18, 00:16 UTCJul 18, 00:55 UTC39m
2026-07-17 UAL8170 ORD → CVG Jul 17, 22:00 UTCJul 17, 22:40 UTC40m
2026-07-17 UAL8170 ORD → CVG Jul 17, 21:48 UTCJul 17, 22:36 UTC48m
2026-07-17 UAL1983 - Jul 17, 16:59 UTCJul 17, 19:45 UTC2h 45m
2026-07-17 UAL1073 IAD → MIA Jul 17, 13:05 UTCJul 17, 15:15 UTC2h 10m
2026-07-17 UAL1252 - Jul 17, 10:10 UTCJul 17, 10:55 UTC45m
2026-07-17 UAL457 ORD → CLE Jul 17, 03:20 UTCJul 17, 04:04 UTC45m
2026-07-16 UAL2040 BOS → ORD Jul 16, 21:19 UTCJul 16, 23:49 UTC2h 30m
2026-07-16 UAL1015 - Jul 16, 14:10 UTCJul 16, 19:14 UTC5h 5m
2026-07-16 UAL1947 - Jul 16, 02:05 UTCJul 16, 02:20 UTC15m
2026-07-16 UAL1947 HNL → SFO Jul 16, 02:08 UTCJul 16, 06:40 UTC4h 32m
2026-07-15 UAL1260 SFO → HNL Jul 15, 19:42 UTCJul 16, 00:33 UTC4h 51m
2026-07-15 UAL1260 - Jul 15, 19:35 UTCJul 15, 20:00 UTC25m

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 N37577 page for operator, model, and routing details .

Mode-S A449CB frequently asked

What is Mode-S code A449CB?
A449CB is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N37577.
Where is Mode-S A449CB registered?
Mode-S code A449CB 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 A449CB broadcasting right now?
Yes. Mode-S A449CB is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A449CB, octal 51044713, decimal 10,766,795.
What flights does A449CB operate?
Mode-S A449CB has broadcast 20 distinct callsigns, including UAL1742, UAL639, UAL2182, UAL1904, UAL797.