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sensors Mode-S transponder

AA1FFC

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N751YX · EMBRAER ERJ-170-200 (long wing) · operated by UNITED AIRLINES INC

Hex
AA1FFC
Octal
52417774
Decimal
11,149,308
Country
US
Tail
N751YX
Type
E75L
No current signal · last broadcast 2d ago
Flights observed
602
Distinct callsigns
20
Country
US
Last broadcast
2d ago

Last known position

Most recent position reported by Mode-S AA1FFC.

Country allocation

The ICAO 24-bit address AA1FFC 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
RPA3572 Republic Airlines 11 2026-05-17
RPA3634 Republic Airlines 7 2026-05-17
RPA3424 Republic Airlines 7 2026-06-01
RPA3705 - 6 2026-06-29
RPA3620 - 6 2026-07-07
RPA3503 Republic Airlines 6 2026-06-01
RPA3495 Republic Airlines 6 2026-05-17
RPA3452 Republic Airlines 6 2026-06-01
RPA3448 Republic Airlines 6 2026-06-15
RPA3404 Republic Airlines 6 2026-05-21
RPA3709 - 5 2026-07-09
RPA3708 Republic Airlines 5 2026-05-03
RPA3679 - 5 2026-07-08
RPA3662 - 5 2026-06-20
RPA3657 - 5 2026-07-09
RPA3639 Republic Airlines 5 2026-06-09
RPA3594 - 5 2026-06-16
RPA3593 - 5 2026-07-02
RPA3591 - 5 2026-07-03
RPA3590 - 5 2026-06-14

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-12 RPA3519 EWR → IND Jul 12, 00:10 UTCJul 12, 01:55 UTC1h 45m
2026-07-11 RPA3562 - Jul 11, 17:00 UTCJul 11, 19:00 UTC2h 0m
2026-07-11 RPA3562 MSP → EWR Jul 11, 17:06 UTCJul 11, 19:18 UTC2h 12m
2026-07-11 RPA3649 IAD → MSP Jul 11, 14:00 UTCJul 11, 16:10 UTC2h 10m
2026-07-11 RPA3543 BOS → IAD Jul 11, 01:35 UTCJul 11, 02:45 UTC1h 10m
2026-07-10 RPA3615 IAD → BOS Jul 10, 20:15 UTCJul 10, 21:15 UTC1h 0m
2026-07-09 RPA3709 - Jul 9, 14:25 UTCJul 9, 15:40 UTC1h 15m
2026-07-09 RPA3709 IND → IAD Jul 9, 14:36 UTCJul 9, 15:38 UTC1h 2m
2026-07-09 RPA3550 - Jul 9, 12:55 UTCJul 9, 13:30 UTC35m
2026-07-09 RPA3479 - Jul 9, 10:10 UTCJul 9, 10:55 UTC45m
2026-07-09 RPA3479 IND → ORD Jul 9, 10:20 UTCJul 9, 10:42 UTC22m
2026-07-09 RPA3660 - Jul 9, 03:20 UTCJul 9, 03:50 UTC30m
2026-07-09 RPA3660 ORD → IND Jul 9, 02:58 UTCJul 9, 03:44 UTC46m
2026-07-09 RPA3657 - Jul 9, 00:35 UTCJul 9, 01:25 UTC50m
2026-07-09 RPA3657 IND → ORD Jul 9, 00:24 UTCJul 9, 01:06 UTC42m
2026-07-08 RPA3585 IAD → IND Jul 8, 21:40 UTCJul 8, 22:55 UTC1h 15m
2026-07-08 RPA3695 MSP → IAD Jul 8, 17:25 UTCJul 8, 19:25 UTC2h 0m
2026-07-08 RPA3649 IAD → MSP Jul 8, 13:06 UTCJul 8, 15:09 UTC2h 3m
2026-07-08 RPA3649 IAD → MSP Jul 8, 13:05 UTCJul 8, 15:10 UTC2h 5m
2026-07-08 RPA3679 PIT → IAD Jul 8, 10:26 UTCJul 8, 10:50 UTC24m
2026-07-08 RPA3679 - Jul 8, 10:10 UTCJul 8, 10:50 UTC40m
2026-07-07 RPA3403 - Jul 7, 23:50 UTCJul 8, 00:45 UTC55m
2026-07-07 RPA3620 - Jul 7, 20:05 UTCJul 7, 21:00 UTC55m
2026-07-07 RPA3535 - Jul 7, 17:25 UTCJul 7, 18:35 UTC1h 10m
2026-07-07 RPA3500 - Jul 7, 14:30 UTCJul 7, 15:35 UTC1h 5m
2026-07-07 RPA3672 - Jul 7, 11:45 UTCJul 7, 13:05 UTC1h 20m
2026-07-07 RPA3301 CRE → EWR Jul 7, 02:25 UTCJul 7, 03:55 UTC1h 30m
2026-07-07 RPA3301 MYR → EWR Jul 7, 02:16 UTCJul 7, 03:48 UTC1h 32m
2026-07-06 RPA3589 - Jul 6, 23:25 UTCJul 7, 01:10 UTC1h 45m
2026-07-06 RPA3568 - Jul 6, 20:05 UTCJul 6, 21:25 UTC1h 20m
2026-07-06 RPA3673 EWR → YQB Jul 6, 15:12 UTCJul 6, 16:10 UTC58m
2026-07-06 RPA3673 - Jul 6, 15:10 UTCJul 6, 16:20 UTC1h 10m
2026-07-05 RPA3633 - Jul 5, 23:25 UTCJul 6, 00:30 UTC1h 5m
2026-07-05 RPA3616 EWR → CLE Jul 5, 18:55 UTCJul 5, 20:15 UTC1h 20m
2026-07-05 RPA3480 - Jul 5, 16:20 UTCJul 5, 17:30 UTC1h 10m
2026-07-05 RPA3641 EWR → CMH Jul 5, 13:00 UTCJul 5, 14:10 UTC1h 10m
2026-07-05 RPA3691 ORF → EWR Jul 5, 03:50 UTCJul 5, 04:00 UTC10m
2026-07-05 RPA3691 ORF → EWR Jul 5, 02:25 UTCJul 5, 04:00 UTC1h 35m
2026-07-05 RPA3691 ORF → EWR Jul 5, 02:22 UTCJul 5, 03:31 UTC1h 9m
2026-07-04 RPA3509 ORD → YOW Jul 4, 19:26 UTCJul 4, 21:00 UTC1h 34m
2026-07-04 RPA3687 JAX → EWR Jul 4, 17:00 UTCJul 4, 17:30 UTC30m
2026-07-04 RPA3486 EWR → DCA Jul 4, 13:20 UTCJul 4, 14:50 UTC1h 30m
2026-07-04 RPA3423 - Jul 4, 10:00 UTCJul 4, 11:30 UTC1h 30m
2026-07-04 RPA3667 EWR → CVG Jul 4, 04:50 UTCJul 4, 06:20 UTC1h 30m
2026-07-04 RPA3667 EWR → CVG Jul 4, 04:53 UTCJul 4, 06:07 UTC1h 14m
2026-07-03 RPA3591 - Jul 3, 15:15 UTCJul 3, 16:05 UTC50m
2026-07-03 RPA3591 BTV → EWR Jul 3, 15:19 UTCJul 3, 16:04 UTC45m
2026-07-03 RPA3505 IAD → BTV Jul 3, 12:56 UTCJul 3, 13:52 UTC56m
2026-07-03 RPA3505 IAD → BTV Jul 3, 12:50 UTCJul 3, 13:55 UTC1h 5m
2026-07-03 RPA3693 - Jul 3, 10:15 UTCJul 3, 10:55 UTC40m

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 N751YX page for operator, model, and routing details .

Mode-S AA1FFC frequently asked

What is Mode-S code AA1FFC?
AA1FFC is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N751YX.
Where is Mode-S AA1FFC registered?
Mode-S code AA1FFC 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 AA1FFC broadcasting right now?
No active broadcast right now. Last signal was 2d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA1FFC, octal 52417774, decimal 11,149,308.
What flights does AA1FFC operate?
Mode-S AA1FFC has broadcast 20 distinct callsigns, including RPA3572, RPA3634, RPA3424, RPA3705, RPA3620.