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sensors Mode-S transponder

AC22E4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N881PU · operated by TRUSTEES OF PURDUE UNIVERSITY

Hex
AC22E4
Octal
53021344
Decimal
11,281,124
Country
US
Tail
N881PU
No current signal · last broadcast 4h ago
Flights observed
189
Distinct callsigns
1
Country
US
Last broadcast
4h ago

Last known position

Most recent position reported by Mode-S AC22E4.

Country allocation

The ICAO 24-bit address AC22E4 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 1 distinct

Callsign Airline Flights Last seen
PDU81 - 189 2026-07-14

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 PDU81 - Jul 14, 16:30 UTCJul 14, 17:30 UTC1h 0m
2026-07-14 PDU81 LAF → LAF Jul 14, 14:00 UTCJul 14, 15:15 UTC1h 15m
2026-07-13 PDU81 - Jul 13, 21:00 UTCJul 13, 22:05 UTC1h 5m
2026-07-13 PDU81 - Jul 13, 18:55 UTCJul 13, 20:15 UTC1h 20m
2026-07-13 PDU81 - Jul 13, 11:55 UTCJul 13, 14:25 UTC2h 30m
2026-07-10 PDU81 LAF → LAF Jul 10, 12:50 UTCJul 10, 14:20 UTC1h 30m
2026-07-09 PDU81 - Jul 9, 20:15 UTCJul 9, 21:10 UTC55m
2026-07-09 PDU81 - Jul 9, 17:00 UTCJul 9, 18:55 UTC1h 55m
2026-07-09 PDU81 LAF → LAF Jul 9, 11:40 UTCJul 9, 13:35 UTC1h 55m
2026-07-08 PDU81 LAF → LAF Jul 8, 22:45 UTCJul 9, 00:00 UTC1h 15m
2026-07-08 PDU81 LAF → LAF Jul 8, 18:35 UTCJul 8, 20:15 UTC1h 40m
2026-07-08 PDU81 LAF → LAF Jul 8, 14:40 UTCJul 8, 16:10 UTC1h 30m
2026-07-08 PDU81 LAF → LAF Jul 8, 11:35 UTCJul 8, 13:30 UTC1h 55m
2026-07-08 PDU81 - Jul 8, 02:30 UTCJul 8, 04:55 UTC2h 25m
2026-07-07 PDU81 - Jul 7, 16:05 UTCJul 7, 17:15 UTC1h 10m
2026-07-07 PDU81 - Jul 7, 13:10 UTCJul 7, 14:15 UTC1h 5m
2026-07-06 PDU81 - Jul 6, 18:55 UTCJul 6, 20:20 UTC1h 25m
2026-07-02 PDU81 LAF → LAF Jul 2, 14:45 UTCJul 2, 16:10 UTC1h 25m
2026-07-01 PDU81 LAF → LAF Jul 1, 17:10 UTCJul 1, 18:30 UTC1h 20m
2026-07-01 PDU81 LAF → LAF Jul 1, 15:05 UTCJul 1, 16:15 UTC1h 10m
2026-07-01 PDU81 - Jul 1, 01:50 UTCJul 1, 05:15 UTC3h 25m
2026-06-30 PDU81 LAF → LAF Jun 30, 19:10 UTCJun 30, 20:25 UTC1h 15m
2026-06-30 PDU81 LAF → LAF Jun 30, 15:50 UTCJun 30, 17:15 UTC1h 25m
2026-06-29 PDU81 - Jun 29, 21:50 UTCJun 29, 22:10 UTC20m
2026-06-29 PDU81 - Jun 29, 20:00 UTCJun 29, 21:09 UTC1h 10m
2026-06-29 PDU81 - Jun 29, 12:05 UTCJun 29, 13:00 UTC55m
2026-06-27 PDU81 - Jun 27, 19:00 UTCJun 27, 19:59 UTC1h 0m
2026-06-26 PDU81 - Jun 26, 12:59 UTCJun 26, 13:49 UTC50m
2026-06-25 PDU81 LAF → LAF Jun 25, 21:59 UTCJun 25, 23:30 UTC1h 30m
2026-06-25 PDU81 LAF → LAF Jun 25, 14:44 UTCJun 25, 16:09 UTC1h 25m
2026-06-24 PDU81 LAF → LAF Jun 24, 21:04 UTCJun 24, 22:10 UTC1h 5m
2026-06-24 PDU81 LAF → LAF Jun 24, 18:29 UTCJun 24, 19:15 UTC45m
2026-06-24 PDU81 LAF → LAF Jun 24, 15:59 UTCJun 24, 17:10 UTC1h 10m
2026-06-23 PDU81 - Jun 23, 14:55 UTCJun 23, 16:05 UTC1h 10m
2026-06-23 PDU81 LAF → LAF Jun 23, 12:49 UTCJun 23, 13:55 UTC1h 5m
2026-06-22 PDU81 - Jun 22, 22:34 UTCJun 23, 00:04 UTC1h 30m
2026-06-22 PDU81 LAF → LAF Jun 22, 21:14 UTCJun 22, 22:05 UTC50m
2026-06-22 PDU81 - Jun 22, 18:04 UTCJun 22, 20:00 UTC1h 55m
2026-06-22 PDU81 - Jun 22, 14:10 UTCJun 22, 14:55 UTC45m
2026-06-22 PDU81 - Jun 22, 12:34 UTCJun 22, 12:59 UTC25m
2026-06-20 PDU81 - Jun 20, 20:55 UTCJun 20, 21:34 UTC40m
2026-06-20 PDU81 - Jun 20, 18:24 UTCJun 20, 18:59 UTC35m
2026-06-20 PDU81 LAF → LAF Jun 20, 15:49 UTCJun 20, 17:04 UTC1h 15m
2026-06-20 PDU81 LAF → LAF Jun 20, 13:14 UTCJun 20, 14:29 UTC1h 15m
2026-06-19 PDU81 LAF → LAF Jun 19, 21:09 UTCJun 19, 22:14 UTC1h 5m
2026-06-19 PDU81 LAF → LAF Jun 19, 16:55 UTCJun 19, 18:25 UTC1h 30m
2026-06-19 PDU81 LAF → LAF Jun 19, 14:49 UTCJun 19, 16:14 UTC1h 25m
2026-06-19 PDU81 LAF → LAF Jun 19, 13:09 UTCJun 19, 14:44 UTC1h 35m
2026-06-19 PDU81 LAF → LAF Jun 19, 02:19 UTCJun 19, 05:09 UTC2h 50m
2026-06-18 PDU81 LAF → LAF Jun 18, 22:50 UTCJun 19, 00:20 UTC1h 29m

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 N881PU page for operator, model, and routing details .

Mode-S AC22E4 frequently asked

What is Mode-S code AC22E4?
AC22E4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N881PU.
Where is Mode-S AC22E4 registered?
Mode-S code AC22E4 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 AC22E4 broadcasting right now?
No active broadcast right now. Last signal was 4h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AC22E4, octal 53021344, decimal 11,281,124.
What flights does AC22E4 operate?
Mode-S AC22E4 has broadcast 1 distinct callsign, including PDU81.