sensors Mode-S transponder
A536DE
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N435NA · AIRBUS HELICOPTERS EC-135/635 · operated by NATIONAL AERONAUTICS AND SPACE ADMINISTRATION, C/O JOHN GRAVES
- Hex
- A536DE
- Octal
- 51233336
- Decimal
- 10,827,486
- Country
- US
- Tail
- N435NA
- Type
- EC35
- Flights observed
- 29
- Distinct callsigns
- 1
- Country
- US
- Last broadcast
- Jul 23, 14:45 UTC
Last known position
Country allocation
The ICAO 24-bit address A536DE 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 |
|---|---|---|---|
| NASA435 | - | 29 | 2026-07-23 |
Recent flights last 29
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-23 | NASA435 | - | Jul 23, 14:30 UTC | Jul 23, 14:45 UTC | 15m |
| 2026-07-21 | NASA435 | - | Jul 21, 14:30 UTC | Jul 21, 14:45 UTC | 15m |
| 2026-07-21 | NASA435 | - | Jul 21, 13:05 UTC | Jul 21, 13:25 UTC | 20m |
| 2026-07-17 | NASA435 | - | Jul 17, 16:00 UTC | Jul 17, 16:59 UTC | 1h 0m |
| 2026-07-16 | NASA435 | - | Jul 16, 14:35 UTC | Jul 16, 15:25 UTC | 50m |
| 2026-07-15 | NASA435 | - | Jul 15, 14:00 UTC | Jul 15, 15:30 UTC | 1h 30m |
| 2026-07-13 | NASA435 | - | Jul 13, 14:05 UTC | Jul 13, 15:05 UTC | 1h 0m |
| 2026-07-09 | NASA435 | - | Jul 9, 15:25 UTC | Jul 9, 15:50 UTC | 25m |
| 2026-07-07 | NASA435 | - | Jul 7, 14:00 UTC | Jul 7, 14:25 UTC | 25m |
| 2026-07-02 | NASA435 | - | Jul 2, 14:30 UTC | Jul 2, 15:05 UTC | 35m |
| 2026-06-30 | NASA435 | - | Jun 30, 18:20 UTC | Jun 30, 19:20 UTC | 1h 0m |
| 2026-06-25 | NASA435 | - | Jun 25, 16:05 UTC | Jun 25, 16:35 UTC | 30m |
| 2026-06-23 | NASA435 | - | Jun 23, 13:05 UTC | Jun 23, 14:49 UTC | 1h 45m |
| 2026-06-18 | NASA435 | - | Jun 18, 18:25 UTC | Jun 18, 19:10 UTC | 45m |
| 2026-06-11 | NASA435 | - | Jun 11, 18:45 UTC | Jun 11, 19:35 UTC | 50m |
| 2026-06-05 | NASA435 | - | Jun 5, 13:00 UTC | Jun 5, 14:45 UTC | 1h 45m |
| 2026-05-29 | NASA435 | - | May 29, 21:05 UTC | May 29, 22:00 UTC | 55m |
| 2026-05-29 | NASA435 | - | May 29, 15:25 UTC | May 29, 15:45 UTC | 20m |
| 2026-05-28 | NASA435 | - | May 28, 13:40 UTC | May 28, 14:35 UTC | 55m |
| 2026-05-26 | NASA435 | - | May 26, 14:24 UTC | May 26, 15:14 UTC | 50m |
| 2026-05-21 | NASA435 | - | May 21, 18:35 UTC | May 21, 19:35 UTC | 1h 0m |
| 2026-05-19 | NASA435 | - | May 19, 15:05 UTC | May 19, 15:55 UTC | 50m |
| 2026-05-19 | NASA435 | - | May 19, 13:55 UTC | May 19, 14:25 UTC | 30m |
| 2026-05-14 | NASA435 | - | May 14, 18:10 UTC | May 14, 18:25 UTC | 15m |
| 2026-05-07 | NASA435 | - | May 7, 18:40 UTC | May 7, 19:15 UTC | 35m |
| 2026-04-24 | NASA435 | - | Apr 24, 13:05 UTC | Apr 24, 13:30 UTC | 25m |
| 2026-04-21 | NASA435 | - | Apr 21, 01:20 UTC | Apr 21, 01:45 UTC | 25m |
| 2026-04-16 | NASA435 | - | Apr 16, 15:15 UTC | Apr 16, 16:15 UTC | 1h 0m |
| 2026-04-16 | NASA435 | - | Apr 16, 14:50 UTC | Apr 16, 15:10 UTC | 20m |
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 N435NA page for operator, model, and routing details .