Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

A4943F

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N39416 · BOEING 737-900 · operated by UNITED AIRLINES INC

Hex
A4943F
Octal
51112077
Decimal
10,785,855
Country
US
Tail
N39416
Type
B739
No current signal · last broadcast Jul 26, 21:45 UTC
Flights observed
440
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:45 UTC

Last known position

Most recent position reported by Mode-S A4943F.

Country allocation

The ICAO 24-bit address A4943F 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
UAL2194 - 6 2026-07-17
UAL1573 - 6 2026-06-16
UAL2463 - 5 2026-06-16
UAL1689 - 5 2026-06-15
UAL572 United Airlines 4 2026-04-26
UAL1893 - 4 2026-06-17
UAL1761 United Airlines 4 2026-06-02
UAL1511 United Airlines 4 2026-05-16
UAL1349 United Airlines 4 2026-07-22
UAL1275 United Airlines 4 2026-07-24
UAL717 - 3 2026-04-13
UAL624 - 3 2026-07-13
UAL555 United Airlines 3 2026-04-28
UAL531 United Airlines 3 2026-05-23
UAL279 - 3 2026-07-08
UAL2669 United Airlines 3 2026-06-04
UAL2375 United Airlines 3 2026-04-16
UAL2290 United Airlines 3 2026-05-28
UAL210 - 3 2026-07-05
UAL2022 United Airlines 3 2026-05-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 UAL455 ORD → MSN Jul 26, 19:00 UTCJul 26, 21:45 UTC2h 45m
2026-07-26 UAL1334 EWR → PBI Jul 26, 15:25 UTCJul 26, 16:40 UTC1h 15m
2026-07-26 UAL1334 EWR → PBI Jul 26, 15:19 UTCJul 26, 16:26 UTC1h 7m
2026-07-26 UAL2247 SFO → IAD Jul 26, 12:35 UTCJul 26, 13:40 UTC1h 5m
2026-07-26 UAL2247 SFO → IAD Jul 26, 12:42 UTCJul 26, 13:36 UTC54m
2026-07-26 UAL1962 MCO → ORD Jul 26, 06:50 UTCJul 26, 10:30 UTC3h 40m
2026-07-25 UAL1277 CUN → LAX Jul 25, 23:10 UTCJul 26, 03:15 UTC4h 5m
2026-07-25 UAL1278 ORD → MSN Jul 25, 17:20 UTCJul 25, 21:45 UTC4h 25m
2026-07-25 UAL2373 LAX → KOA Jul 25, 11:15 UTCJul 25, 14:50 UTC3h 35m
2026-07-25 UAL1754 MSN → ORD Jul 25, 02:20 UTCJul 25, 06:00 UTC3h 40m
2026-07-24 UAL1275 SFO → RNO Jul 24, 20:05 UTCJul 25, 00:20 UTC4h 15m
2026-07-24 UAL1275 SFO → RNO Jul 24, 20:07 UTCJul 25, 00:16 UTC4h 9m
2026-07-24 UAL1198 LAS → ORD Jul 24, 14:45 UTCJul 24, 17:45 UTC3h 0m
2026-07-24 UAL2070 SFO → PDX Jul 24, 10:35 UTCJul 24, 12:10 UTC1h 35m
2026-07-23 UAL2202 ORD → EWR Jul 23, 23:55 UTCJul 24, 01:10 UTC1h 15m
2026-07-23 UAL2179 LGA → ORD Jul 23, 19:20 UTCJul 23, 21:30 UTC2h 10m
2026-07-23 UAL1850 IAH → SFO Jul 23, 16:15 UTCJul 23, 17:45 UTC1h 30m
2026-07-23 UAL1850 IAH → SFO Jul 23, 16:16 UTCJul 23, 18:01 UTC1h 45m
2026-07-23 UAL567 BOS → ORD Jul 23, 12:50 UTCJul 23, 13:45 UTC55m
2026-07-23 UAL1131 DEN → SAT Jul 23, 03:10 UTCJul 23, 04:10 UTC1h 0m
2026-07-22 UAL1494 ANC → SFO Jul 22, 22:40 UTCJul 22, 23:55 UTC1h 15m
2026-07-22 UAL1349 RSW → IAD Jul 22, 20:10 UTCJul 22, 21:05 UTC55m
2026-07-22 UAL664 - Jul 22, 14:35 UTCJul 22, 17:45 UTC3h 10m
2026-07-21 UAL2658 IAH → MCO Jul 21, 23:00 UTCJul 22, 01:45 UTC2h 45m
2026-07-21 UAL1056 SFO → CMH Jul 21, 18:55 UTCJul 21, 20:50 UTC1h 55m
2026-07-21 UAL1014 IAH → CUN Jul 21, 15:30 UTCJul 21, 17:15 UTC1h 45m
2026-07-21 UAL2474 SFO → BOS Jul 21, 00:15 UTCJul 21, 02:25 UTC2h 10m
2026-07-20 UAL462 EWR → PBI Jul 20, 20:30 UTCJul 20, 22:50 UTC2h 20m
2026-07-20 UAL462 EWR → PBI Jul 20, 20:32 UTCJul 20, 22:38 UTC2h 6m
2026-07-20 UAL686 - Jul 20, 14:20 UTCJul 20, 17:55 UTC3h 35m
2026-07-20 UAL367 DEN → BOI Jul 20, 02:50 UTCJul 20, 07:40 UTC4h 50m
2026-07-19 UAL1635 LAX → IAD Jul 19, 20:05 UTCJul 20, 00:45 UTC4h 40m
2026-07-19 UAL1653 - Jul 19, 14:05 UTCJul 19, 18:20 UTC4h 15m
2026-07-19 UAL1653 CUN → LAX Jul 19, 13:49 UTCJul 19, 18:16 UTC4h 27m
2026-07-19 UAL1145 - Jul 19, 07:30 UTCJul 19, 12:25 UTC4h 55m
2026-07-19 UAL1267 LAS → SFO Jul 19, 03:55 UTCJul 19, 05:00 UTC1h 5m
2026-07-18 UAL2658 - Jul 18, 22:55 UTCJul 19, 01:35 UTC2h 40m
2026-07-18 UAL744 - Jul 18, 19:50 UTCJul 18, 20:20 UTC30m
2026-07-18 UAL1859 - Jul 18, 17:50 UTCJul 18, 18:20 UTC30m
2026-07-18 UAL1859 PIT → IAH Jul 18, 18:01 UTCJul 18, 18:16 UTC15m
2026-07-18 UAL2608 - Jul 18, 13:30 UTCJul 18, 16:05 UTC2h 35m
2026-07-18 UAL2242 ORD → SFO Jul 18, 02:45 UTCJul 18, 05:50 UTC3h 6m
2026-07-17 UAL433 - Jul 17, 22:29 UTCJul 18, 00:50 UTC2h 20m
2026-07-17 UAL1554 SJC → DEN Jul 17, 17:30 UTCJul 17, 19:00 UTC1h 30m
2026-07-17 UAL1554 SJC → DEN Jul 17, 17:37 UTCJul 17, 18:59 UTC1h 22m
2026-07-17 UAL1695 EWR → MCO Jul 17, 12:25 UTCJul 17, 14:20 UTC1h 55m
2026-07-17 UAL1722 OGG → SFO Jul 17, 07:20 UTCJul 17, 10:35 UTC3h 15m
2026-07-17 UAL1722 OGG → SFO Jul 17, 07:22 UTCJul 17, 10:29 UTC3h 7m
2026-07-17 UAL2194 - Jul 17, 02:10 UTCJul 17, 06:00 UTC3h 50m
2026-07-16 UAL782 - Jul 16, 20:15 UTCJul 16, 22:40 UTC2h 25m

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 N39416 page for operator, model, and routing details .

Mode-S A4943F frequently asked

What is Mode-S code A4943F?
A4943F is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N39416.
Where is Mode-S A4943F registered?
Mode-S code A4943F 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 A4943F broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4943F, octal 51112077, decimal 10,785,855.
What flights does A4943F operate?
Mode-S A4943F has broadcast 20 distinct callsigns, including UAL2194, UAL1573, UAL2463, UAL1689, UAL572.