sensors Mode-S transponder

491D8D

ICAO 24-bit transponder address · allocated to Portugal

Currently assigned to CS-GLM · BOMBARDIER BD-700 Global 5000/5500

Hex
491D8D
Octal
22216615
Decimal
4,791,693
Country
PT
Tail
CS-GLM
Type
GL5T
No current signal · last broadcast 1h ago
Flights observed
9
Distinct callsigns
4
Country
PT
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S 491D8D.

Country allocation

The ICAO 24-bit address 491D8D falls within the block assigned to Portugal (PT) by ICAO Annex 10, Volume III. Every aircraft registered in Portugal 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 4 distinct

Callsign Airline Flights Last seen
NJE2RB - 5 2026-04-16
NJE206K - 2 2026-04-17
NJE331T - 1 2026-04-17
NJE257E - 1 2026-04-18

Recent flights last 9

DateFlightRouteTakeoffLandingDuration
2026-04-18 NJE257E - Apr 18, 07:40 UTCApr 18, 17:15 UTC9h 35m
2026-04-17 NJE206K - Apr 17, 15:20 UTCApr 17, 17:00 UTC1h 40m
2026-04-17 NJE206K - Apr 17, 14:30 UTCApr 17, 15:15 UTC45m
2026-04-17 NJE331T - Apr 17, 12:30 UTCApr 17, 13:15 UTC45m
2026-04-16 NJE2RB - Apr 16, 09:10 UTCApr 16, 10:09 UTC1h 0m
2026-04-16 NJE2RB - Apr 16, 08:09 UTCApr 16, 09:05 UTC55m
2026-04-16 NJE2RB - Apr 16, 01:10 UTCApr 16, 01:40 UTC30m
2026-04-14 NJE2RB - Apr 14, 17:05 UTCApr 14, 17:20 UTC15m
2026-04-12 NJE2RB - Apr 12, 17:15 UTCApr 12, 18:15 UTC1h 0m

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 CS-GLM page for operator, model, and routing details .

Mode-S 491D8D frequently asked

What is Mode-S code 491D8D?
491D8D is an ICAO 24-bit transponder address. Allocated to Portugal. Assigned to CS-GLM.
Where is Mode-S 491D8D registered?
Mode-S code 491D8D is allocated to Portugal (PT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 491D8D broadcasting right now?
No active broadcast right now. Last signal was 1h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 491D8D, octal 22216615, decimal 4,791,693.
What flights does 491D8D operate?
Mode-S 491D8D has broadcast 4 distinct callsigns, including NJE2RB, NJE206K, NJE331T, NJE257E.