Apparatus

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sensors Mode-S transponder

AA39FD

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N758YX · EMBRAER ERJ-170-200 (long wing) · operated by REPUBLIC AIRWAYS INC

Hex
AA39FD
Octal
52434775
Decimal
11,155,965
Country
US
Tail
N758YX
Type
E75L
No current signal · last broadcast Jul 26, 20:20 UTC
Flights observed
605
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 20:20 UTC

Last known position

Most recent position reported by Mode-S AA39FD.

Country allocation

The ICAO 24-bit address AA39FD 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
RPA3696 Republic Airlines 10 2026-07-24
RPA3656 - 8 2026-07-08
RPA3624 Republic Airlines 8 2026-07-17
RPA3473 Republic Airlines 7 2026-06-12
RPA3708 - 6 2026-07-11
RPA3685 - 6 2026-07-02
RPA3631 - 6 2026-07-05
RPA3629 Republic Airlines 6 2026-06-06
RPA3617 Republic Airlines 6 2026-06-19
RPA3596 - 6 2026-07-02
RPA3587 - 6 2026-07-11
RPA3563 - 6 2026-06-26
RPA3495 - 6 2026-07-12
RPA3487 Republic Airlines 6 2026-07-22
RPA3426 Republic Airlines 6 2026-07-22
RPA3669 - 5 2026-07-09
RPA3605 - 5 2026-06-30
RPA3553 - 5 2026-06-19
RPA3510 Republic Airlines 5 2026-07-03
RPA3507 - 5 2026-06-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 RPA3530 EWR → SAV Jul 26, 19:00 UTCJul 26, 20:10 UTC1h 10m
2026-07-26 RPA3446 CLT → EWR Jul 26, 16:05 UTCJul 26, 17:40 UTC1h 35m
2026-07-26 RPA3482 DCA → EWR Jul 26, 11:40 UTCJul 26, 13:25 UTC1h 45m
2026-07-25 RPA3620 ORF → EWR Jul 25, 23:15 UTCJul 26, 01:15 UTC2h 0m
2026-07-25 RPA3450 DCA → EWR Jul 25, 18:50 UTCJul 25, 20:10 UTC1h 20m
2026-07-25 RPA3450 DCA → EWR Jul 25, 18:58 UTCJul 25, 19:55 UTC57m
2026-07-25 RPA3450 DCA → EWR Jul 25, 15:45 UTCJul 25, 17:20 UTC1h 35m
2026-07-25 RPA3429 MEM → EWR Jul 25, 11:35 UTCJul 25, 12:25 UTC50m
2026-07-24 RPA3545 EWR → CMH Jul 24, 22:10 UTCJul 24, 23:25 UTC1h 15m
2026-07-24 RPA3686 DCA → ORD Jul 24, 19:15 UTCJul 24, 20:15 UTC1h 0m
2026-07-24 RPA3457 EWR → ATL Jul 24, 16:15 UTCJul 24, 17:45 UTC1h 30m
2026-07-24 RPA3696 EWR → CLT Jul 24, 13:30 UTCJul 24, 14:25 UTC55m
2026-07-24 RPA3696 EWR → CLT Jul 24, 13:17 UTCJul 24, 14:19 UTC1h 2m
2026-07-23 RPA3415 AVL → EWR Jul 23, 22:25 UTCJul 24, 00:05 UTC1h 40m
2026-07-23 RPA3686 DCA → ORD Jul 23, 19:30 UTCJul 23, 20:30 UTC1h 0m
2026-07-23 RPA3686 DCA → ORD Jul 23, 19:28 UTCJul 23, 20:19 UTC51m
2026-07-23 RPA3457 EWR → ATL Jul 23, 16:10 UTCJul 23, 17:45 UTC1h 35m
2026-07-23 RPA3696 EWR → CLT Jul 23, 14:30 UTCJul 23, 14:35 UTC5m
2026-07-23 RPA3696 EWR → CLT Jul 23, 13:25 UTCJul 23, 14:35 UTC1h 10m
2026-07-23 RPA3696 EWR → CLT Jul 23, 13:17 UTCJul 23, 14:15 UTC58m
2026-07-22 RPA3598 - Jul 22, 23:15 UTCJul 23, 00:05 UTC50m
2026-07-22 RPA3598 ORD → SDF Jul 22, 23:23 UTCJul 23, 00:00 UTC37m
2026-07-22 RPA3426 EYW → EWR Jul 22, 19:30 UTCJul 22, 21:30 UTC2h 0m
2026-07-22 RPA3426 EYW → EWR Jul 22, 19:25 UTCJul 22, 21:15 UTC1h 50m
2026-07-22 RPA3487 YYZ → EWR Jul 22, 17:05 UTCJul 22, 18:20 UTC1h 15m
2026-07-22 RPA3717 - Jul 22, 14:20 UTCJul 22, 15:35 UTC1h 15m
2026-07-21 RPA3295 TUL → IAH Jul 21, 20:00 UTCJul 21, 22:10 UTC2h 10m
2026-07-21 RPA3295 TUL → IAH Jul 21, 19:33 UTCJul 21, 22:11 UTC2h 38m
2026-07-21 RPA3312 ITH → MKE Jul 21, 15:05 UTCJul 21, 16:40 UTC1h 35m
2026-07-20 RPA3586 EWR → GSO Jul 20, 22:25 UTCJul 20, 23:45 UTC1h 20m
2026-07-20 RPA3686 - Jul 20, 19:25 UTCJul 20, 20:20 UTC55m
2026-07-20 RPA3457 EWR → ATL Jul 20, 16:20 UTCJul 20, 17:15 UTC55m
2026-07-20 RPA3457 EWR → ATL Jul 20, 16:14 UTCJul 20, 17:52 UTC1h 38m
2026-07-20 RPA3696 EWR → CLT Jul 20, 13:15 UTCJul 20, 14:15 UTC1h 0m
2026-07-19 RPA3598 - Jul 19, 23:40 UTCJul 20, 00:30 UTC50m
2026-07-19 RPA3598 ORD → SDF Jul 19, 23:48 UTCJul 20, 00:27 UTC39m
2026-07-19 RPA3426 EYW → EWR Jul 19, 20:15 UTCJul 19, 22:15 UTC2h 0m
2026-07-19 RPA3426 EYW → EWR Jul 19, 20:02 UTCJul 19, 21:55 UTC1h 53m
2026-07-19 RPA3487 - Jul 19, 17:45 UTCJul 19, 19:00 UTC1h 15m
2026-07-18 RPA3463 CVG → EWR Jul 18, 22:15 UTCJul 18, 23:05 UTC50m
2026-07-18 RPA3463 CVG → EWR Jul 18, 22:15 UTCJul 18, 22:49 UTC34m
2026-07-18 RPA3463 CVG → EWR Jul 18, 17:40 UTCJul 18, 19:55 UTC2h 15m
2026-07-18 RPA3463 CVG → EWR Jul 18, 17:45 UTCJul 18, 19:56 UTC2h 11m
2026-07-18 RPA3462 ORD → CVG Jul 18, 14:00 UTCJul 18, 16:05 UTC2h 5m
2026-07-18 RPA3462 ORD → CVG Jul 18, 13:37 UTCJul 18, 16:10 UTC2h 33m
2026-07-18 RPA3551 BOS → EWR Jul 18, 10:00 UTCJul 18, 11:20 UTC1h 20m
2026-07-18 RPA3622 - Jul 18, 02:19 UTCJul 18, 03:30 UTC1h 11m
2026-07-17 RPA3520 EWR → BUF Jul 17, 23:55 UTCJul 18, 00:35 UTC40m
2026-07-17 RPA3624 EWR → ROC Jul 17, 21:55 UTCJul 17, 22:35 UTC40m
2026-07-17 RPA3624 EWR → ROC Jul 17, 21:53 UTCJul 17, 22:32 UTC39m

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 N758YX page for operator, model, and routing details .

Mode-S AA39FD frequently asked

What is Mode-S code AA39FD?
AA39FD is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N758YX.
Where is Mode-S AA39FD registered?
Mode-S code AA39FD 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 AA39FD broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 20:20 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA39FD, octal 52434775, decimal 11,155,965.
What flights does AA39FD operate?
Mode-S AA39FD has broadcast 20 distinct callsigns, including RPA3696, RPA3656, RPA3624, RPA3473, RPA3708.