sensors Mode-S transponder

77181F

ICAO 24-bit transponder address · allocated to Sri Lanka

Currently assigned to 4R-EXR · AIRBUS A-320

Hex
77181F
Octal
35614037
Decimal
7,804,959
Country
LK
Tail
4R-EXR
Type
A320
No current signal · last broadcast 1d ago
Flights observed
5
Distinct callsigns
5
Country
LK
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S 77181F.

Country allocation

The ICAO 24-bit address 77181F falls within the block assigned to Sri Lanka (LK) by ICAO Annex 10, Volume III. Every aircraft registered in Sri Lanka 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 5 distinct

Callsign Airline Flights Last seen
EXV922 - 1 2026-04-13
EXV921 Expo Aviation 1 2026-04-13
EXV912 - 1 2026-04-13
EXV911 - 1 2026-04-13
EXV824 - 1 2026-04-12

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-13 EXV912 - Apr 13, 20:35 UTCApr 13, 22:55 UTC2h 20m
2026-04-13 EXV911 - Apr 13, 16:45 UTCApr 13, 19:00 UTC2h 15m
2026-04-13 EXV922 - Apr 13, 05:30 UTCApr 13, 05:55 UTC25m
2026-04-13 EXV921 CMB → MLE Apr 13, 01:50 UTCApr 13, 02:10 UTC20m
2026-04-12 EXV824 - Apr 12, 17:15 UTCApr 12, 18:00 UTC45m

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 4R-EXR page for operator, model, and routing details .

Mode-S 77181F frequently asked

What is Mode-S code 77181F?
77181F is an ICAO 24-bit transponder address. Allocated to Sri Lanka. Assigned to 4R-EXR.
Where is Mode-S 77181F registered?
Mode-S code 77181F is allocated to Sri Lanka (LK). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 77181F broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 77181F, octal 35614037, decimal 7,804,959.
What flights does 77181F operate?
Mode-S 77181F has broadcast 5 distinct callsigns, including EXV922, EXV921, EXV912, EXV911, EXV824.