Apparatus

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sensors Mode-S transponder

770591

ICAO 24-bit transponder address · allocated to Sri Lanka

Currently assigned to 4R-ALQ · AIRBUS A-330-300

Hex
770591
Octal
35602621
Decimal
7,800,209
Country
LK
Tail
4R-ALQ
Type
A333
No current signal · last broadcast 1h ago
Flights observed
191
Distinct callsigns
20
Country
LK
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S 770591.

Country allocation

The ICAO 24-bit address 770591 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 20 distinct

Callsign Airline Flights Last seen
ALK504 - 33 2026-07-13
ALK503 - 32 2026-07-13
ALK604 - 20 2026-07-02
ALK455 - 14 2026-07-04
ALK26L - 13 2026-06-28
ALK25L SriLankan Airlines 11 2026-06-21
ALK501 SriLankan Airlines 10 2026-05-17
ALK605 - 8 2026-07-02
ALK454 - 8 2026-07-03
ALK266 - 5 2026-06-16
ALK606 - 4 2026-07-04
ALK90L SriLankan Airlines 3 2026-05-04
ALK600 SriLankan Airlines 3 2026-05-29
ALK141 - 3 2026-07-02
ALK89L SriLankan Airlines 2 2026-05-04
ALK607 - 2 2026-07-05
ALK564 - 2 2026-07-12
ALK318 SriLankan Airlines 2 2026-04-14
ALK265 SriLankan Airlines 2 2026-05-21
ALK142 - 2 2026-07-02

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 ALK504 - Jul 13, 20:55 UTCJul 14, 01:15 UTC4h 20m
2026-07-13 ALK503 - Jul 13, 02:05 UTCJul 13, 18:55 UTC16h 50m
2026-07-12 ALK503 - Jul 12, 22:30 UTCJul 13, 18:55 UTC20h 25m
2026-07-12 ALK503 - Jul 12, 20:20 UTCJul 13, 18:55 UTC22h 35m
2026-07-12 ALK503 - Jul 12, 20:01 UTCJul 13, 18:15 UTC22h 15m
2026-07-12 ALK503 - Jul 12, 17:01 UTCJul 13, 16:15 UTC23h 15m
2026-07-12 ALK564 - Jul 12, 14:20 UTCJul 13, 14:15 UTC23h 55m
2026-07-12 ALK564 - Jul 12, 13:25 UTCJul 13, 11:55 UTC22h 30m
2026-07-11 ALK563 - Jul 11, 20:35 UTCJul 12, 07:01 UTC10h 25m
2026-07-05 ALK607 - Jul 5, 06:50 UTCJul 5, 13:50 UTC7h 0m
2026-07-04 ALK606 - Jul 4, 10:20 UTCJul 5, 04:50 UTC18h 30m
2026-07-04 ALK455 - Jul 4, 09:25 UTCJul 5, 04:50 UTC19h 25m
2026-07-04 ALK455 - Jul 4, 06:20 UTCJul 5, 04:50 UTC22h 30m
2026-07-04 ALK455 - Jul 4, 04:20 UTCJul 5, 04:15 UTC23h 55m
2026-07-04 ALK455 - Jul 4, 04:10 UTCJul 4, 11:00 UTC6h 50m
2026-07-03 ALK454 - Jul 3, 13:00 UTCJul 4, 02:30 UTC13h 30m
2026-07-03 ALK308 - Jul 3, 05:15 UTCJul 3, 11:35 UTC6h 20m
2026-07-02 ALK142 - Jul 2, 22:35 UTCJul 3, 00:10 UTC1h 35m
2026-07-02 ALK141 - Jul 2, 20:00 UTCJul 2, 20:25 UTC25m
2026-07-02 ALK605 - Jul 2, 06:30 UTCJul 2, 19:30 UTC13h 0m
2026-07-02 ALK604 - Jul 2, 03:20 UTCJul 2, 04:35 UTC1h 15m
2026-07-01 ALK604 - Jul 1, 09:45 UTCJul 2, 04:35 UTC18h 50m
2026-07-01 ALK605 MEL → MEL Jul 1, 06:50 UTCJul 2, 04:35 UTC21h 45m
2026-07-01 ALK604 - Jul 1, 03:25 UTCJul 1, 04:40 UTC1h 15m
2026-06-30 ALK604 - Jun 30, 08:20 UTCJul 1, 04:40 UTC20h 20m
2026-06-30 ALK604 - Jun 30, 06:20 UTCJul 1, 04:40 UTC22h 20m
2026-06-30 ALK455 - Jun 30, 06:00 UTCJul 1, 04:15 UTC22h 15m
2026-06-30 ALK455 - Jun 30, 03:10 UTCJun 30, 08:50 UTC5h 40m
2026-06-29 ALK454 - Jun 29, 08:39 UTCJun 29, 23:29 UTC14h 50m
2026-06-28 ALK26L - Jun 28, 19:29 UTCJun 28, 23:29 UTC4h 0m
2026-06-27 ALK504 - Jun 27, 22:20 UTCJun 28, 17:19 UTC19h 0m
2026-06-27 ALK504 - Jun 27, 21:44 UTCJun 28, 17:19 UTC19h 35m
2026-06-27 ALK503 - Jun 27, 08:10 UTCJun 27, 19:05 UTC10h 55m
2026-06-26 ALK103 - Jun 26, 14:19 UTCJun 27, 05:10 UTC14h 50m
2026-06-25 ALK605 - Jun 25, 06:35 UTCJun 25, 07:49 UTC1h 15m
2026-06-25 ALK604 - Jun 25, 01:40 UTCJun 25, 04:35 UTC2h 55m
2026-06-24 ALK604 - Jun 24, 09:15 UTCJun 25, 04:35 UTC19h 20m
2026-06-24 ALK604 MEL → MEL Jun 24, 06:35 UTCJun 25, 04:35 UTC22h 0m
2026-06-24 ALK604 - Jun 24, 03:24 UTCJun 24, 04:30 UTC1h 5m
2026-06-22 ALK504 - Jun 22, 20:55 UTCJun 23, 07:05 UTC10h 10m
2026-06-22 ALK503 - Jun 22, 08:10 UTCJun 22, 19:05 UTC10h 55m
2026-06-21 ALK26L - Jun 21, 22:24 UTCJun 21, 23:10 UTC45m
2026-06-21 ALK26L - Jun 21, 19:20 UTCJun 21, 19:39 UTC20m
2026-06-21 ALK25L CMB → DXB Jun 21, 13:39 UTCJun 21, 14:10 UTC30m
2026-06-20 ALK504 - Jun 20, 20:49 UTCJun 21, 06:10 UTC9h 20m
2026-06-20 ALK503 - Jun 20, 07:59 UTCJun 20, 18:49 UTC10h 50m
2026-06-19 ALK26L - Jun 19, 22:14 UTCJun 19, 23:00 UTC45m
2026-06-19 ALK26L - Jun 19, 19:14 UTCJun 19, 19:34 UTC20m
2026-06-19 ALK25L CMB → DXB Jun 19, 17:19 UTCJun 19, 17:29 UTC10m
2026-06-18 ALK504 - Jun 18, 21:35 UTCJun 19, 14:09 UTC16h 34m

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-ALQ page for operator, model, and routing details .

Mode-S 770591 frequently asked

What is Mode-S code 770591?
770591 is an ICAO 24-bit transponder address. Allocated to Sri Lanka. Assigned to 4R-ALQ.
Where is Mode-S 770591 registered?
Mode-S code 770591 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 770591 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 770591, octal 35602621, decimal 7,800,209.
What flights does 770591 operate?
Mode-S 770591 has broadcast 20 distinct callsigns, including ALK504, ALK503, ALK604, ALK455, ALK26L.