sensors Mode-S transponder

503E77

ICAO 24-bit transponder address · allocated to Lithuania

Currently assigned to LY-API · PIPER PA-28-140/150/160/180

Hex
503E77
Octal
24037167
Decimal
5,258,871
Country
LT
Tail
LY-API
Type
P28A
No current signal · last broadcast 2h ago
Flights observed
7
Distinct callsigns
1
Country
LT
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S 503E77.

Country allocation

The ICAO 24-bit address 503E77 falls within the block assigned to Lithuania (LT) by ICAO Annex 10, Volume III. Every aircraft registered in Lithuania 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
LYAPI - 7 2026-04-18

Recent flights last 7

DateFlightRouteTakeoffLandingDuration
2026-04-18 LYAPI - Apr 18, 14:00 UTCApr 18, 15:20 UTC1h 20m
2026-04-18 LYAPI - Apr 18, 12:50 UTCApr 18, 13:00 UTC10m
2026-04-18 LYAPI - Apr 18, 09:05 UTCApr 18, 11:00 UTC1h 55m
2026-04-17 LYAPI - Apr 17, 15:20 UTCApr 17, 16:30 UTC1h 10m
2026-04-17 LYAPI - Apr 17, 14:40 UTCApr 17, 15:15 UTC34m
2026-04-17 LYAPI - Apr 17, 11:20 UTCApr 17, 12:20 UTC1h 0m
2026-04-17 LYAPI - Apr 17, 06:25 UTCApr 17, 06:35 UTC10m

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 LY-API page for operator, model, and routing details .

Mode-S 503E77 frequently asked

What is Mode-S code 503E77?
503E77 is an ICAO 24-bit transponder address. Allocated to Lithuania. Assigned to LY-API.
Where is Mode-S 503E77 registered?
Mode-S code 503E77 is allocated to Lithuania (LT). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 503E77 broadcasting right now?
No active broadcast right now. Last signal was 2h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 503E77, octal 24037167, decimal 5,258,871.
What flights does 503E77 operate?
Mode-S 503E77 has broadcast 1 distinct callsign, including LYAPI.