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
Broadcasting now · callsign UAL2419 · 35,000 ft
Flights observed
377
Distinct callsigns
20
Country
US
Last broadcast
24m ago

Current position

A4943F is currently broadcasting. Map zoomed to live position.

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
UAL1573 - 6 2026-06-16
UAL2463 - 5 2026-06-16
UAL2194 United Airlines 5 2026-05-01
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
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
UAL2005 - 3 2026-07-09
UAL1992 - 3 2026-07-02

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 UAL2419 - Jul 14, 02:45 UTCJul 14, 03:45 UTC1h 0m
2026-07-13 UAL624 PHX → DEN Jul 13, 23:35 UTCJul 14, 01:05 UTC1h 30m
2026-07-13 UAL624 PHX → DEN Jul 13, 23:37 UTCJul 14, 01:00 UTC1h 23m
2026-07-13 UAL455 - Jul 13, 18:55 UTCJul 13, 21:50 UTC2h 55m
2026-07-13 UAL2171 - Jul 13, 13:30 UTCJul 13, 17:10 UTC3h 40m
2026-07-13 UAL658 ORD → ONT Jul 13, 02:10 UTCJul 13, 05:40 UTC3h 30m
2026-07-12 UAL1494 - Jul 12, 23:00 UTCJul 13, 00:20 UTC1h 20m
2026-07-12 UAL1349 ORD → PIT Jul 12, 20:15 UTCJul 12, 21:10 UTC55m
2026-07-12 UAL2207 PHL → ORD Jul 12, 15:50 UTCJul 12, 17:45 UTC1h 55m
2026-07-12 UAL2038 - Jul 12, 12:50 UTCJul 12, 14:15 UTC1h 25m
2026-07-11 UAL1121 - Jul 11, 20:15 UTCJul 12, 00:10 UTC3h 55m
2026-07-11 UAL1121 - Jul 11, 19:15 UTCJul 11, 19:25 UTC10m
2026-07-11 UAL1121 LIR → ORD Jul 11, 19:19 UTCJul 11, 23:55 UTC4h 36m
2026-07-11 UAL1120 - Jul 11, 13:10 UTCJul 11, 17:05 UTC3h 55m
2026-07-11 UAL1754 LAX → ORD Jul 11, 02:35 UTCJul 11, 06:05 UTC3h 30m
2026-07-11 UAL1754 LAX → ORD Jul 11, 02:28 UTCJul 11, 06:05 UTC3h 37m
2026-07-10 UAL1275 - Jul 10, 19:55 UTCJul 11, 00:35 UTC4h 40m
2026-07-10 UAL1275 CUN → LAX Jul 10, 19:54 UTCJul 11, 00:27 UTC4h 33m
2026-07-10 UAL1198 ORD → CUN Jul 10, 14:45 UTCJul 10, 18:20 UTC3h 35m
2026-07-10 UAL1672 LAS → ORD Jul 10, 03:10 UTCJul 10, 06:00 UTC2h 50m
2026-07-09 UAL1875 ORD → LAS Jul 9, 22:40 UTCJul 10, 02:05 UTC3h 25m
2026-07-09 UAL2784 PHL → ORD Jul 9, 18:55 UTCJul 9, 20:40 UTC1h 45m
2026-07-09 UAL2784 PHL → ORD Jul 9, 18:44 UTCJul 9, 20:22 UTC1h 38m
2026-07-09 UAL2752 ORD → PHL Jul 9, 14:40 UTCJul 9, 16:15 UTC1h 35m
2026-07-09 UAL307 MSP → ORD Jul 9, 11:10 UTCJul 9, 12:35 UTC1h 25m
2026-07-09 UAL2005 ORD → MSP Jul 9, 01:25 UTCJul 9, 02:35 UTC1h 10m
2026-07-08 UAL403 - Jul 8, 20:30 UTCJul 8, 23:05 UTC2h 35m
2026-07-08 UAL279 ORD → FLL Jul 8, 16:25 UTCJul 8, 19:00 UTC2h 35m
2026-07-08 UAL2488 EWR → ORD Jul 8, 12:20 UTCJul 8, 14:30 UTC2h 10m
2026-07-07 UAL733 - Jul 7, 20:00 UTCJul 8, 01:05 UTC5h 5m
2026-07-07 UAL1292 ORD → YVR Jul 7, 14:15 UTCJul 7, 18:10 UTC3h 55m
2026-07-07 UAL2483 - Jul 7, 10:05 UTCJul 7, 11:15 UTC1h 10m
2026-07-06 UAL2827 ORD → TYS Jul 6, 23:28 UTCJul 7, 00:43 UTC1h 15m
2026-07-06 UAL2827 - Jul 6, 23:40 UTCJul 7, 00:50 UTC1h 10m
2026-07-06 UAL1748 IAH → JAX Jul 6, 21:25 UTCJul 6, 21:30 UTC5m
2026-07-06 UAL1748 IAH → JAX Jul 6, 18:25 UTCJul 6, 21:30 UTC3h 5m
2026-07-06 UAL1748 IAH → JAX Jul 6, 18:26 UTCJul 6, 21:10 UTC2h 44m
2026-07-06 UAL659 - Jul 6, 16:05 UTCJul 6, 17:00 UTC55m
2026-07-06 UAL2110 - Jul 6, 11:15 UTCJul 6, 14:05 UTC2h 50m
2026-07-05 UAL1392 - Jul 5, 22:05 UTCJul 6, 02:15 UTC4h 10m
2026-07-05 UAL1536 EWR → BOS Jul 5, 19:30 UTCJul 5, 20:30 UTC1h 0m
2026-07-05 UAL210 - Jul 5, 15:30 UTCJul 5, 18:05 UTC2h 35m
2026-07-05 UAL210 FLL → EWR Jul 5, 15:29 UTCJul 5, 18:03 UTC2h 34m
2026-07-05 UAL1364 - Jul 5, 11:25 UTCJul 5, 13:50 UTC2h 25m
2026-07-04 UAL1206 TPA → EWR Jul 4, 20:35 UTCJul 4, 23:35 UTC3h 0m
2026-07-04 UAL1206 TPA → EWR Jul 4, 20:34 UTCJul 4, 23:29 UTC2h 55m
2026-07-04 UAL2277 IAD → TPA Jul 4, 17:05 UTCJul 4, 19:05 UTC2h 0m
2026-07-04 UAL1392 MSY → IAD Jul 4, 13:05 UTCJul 4, 15:05 UTC2h 0m
2026-07-04 UAL2042 IAD → MSY Jul 4, 00:10 UTCJul 4, 02:10 UTC2h 0m
2026-07-03 UAL721 BOS → IAD Jul 3, 18:55 UTCJul 3, 20:00 UTC1h 5m

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?
Yes. Mode-S A4943F is currently airborne.
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 UAL1573, UAL2463, UAL2194, UAL1689, UAL572.