# N4436A: 1987 Quad City Ultralight CHALLENGER II CWS

- Status: Valid registration
- Airframe: [Quad City Ultralight CHALLENGER II CWS](https://openairdocs.org/model/quad-city-ultralight-challenger-ii-cws) (registry code 05904OX, 2 seats)
- Engine: [Rotax 503 series](https://openairdocs.org/engine/rotax-503-series) (registry code 55564)
- Serial number: TKR0245
- Year built: 1987
- Type: Fixed wing single engine
- Engine type: 2 cycle
- Airworthiness: Experimental, registered before 01/31/08
- Airworthiness date: January 24, 2008
- Certificate issued: November 29, 2016
- Expires: November 30, 2029
- Mode S code: A558ED
- Registered owner: [Robertson Johnny T](https://openairdocs.org/faa-owner/ROBERTSON%20JOHNNY%20T)
- Location: [Slaton, TX](https://openairdocs.org/faa-place/TX/Slaton)
- Owner type: Individual
- Owner's area on the map: 33.4455° N, 101.6319° W: Placed by OpenAirDocs at the center of ZIP code 79364, within about 8 miles (OpenAirDocs). The owner's mailing address, not where the aircraft is based
- FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=4436A
- Page: https://openairdocs.org/aircraft/N4436A

From the FAA registry file of October 24, 2026. ADs below are matched by the registry's airframe and engine model codes. They may apply; each AD's applicability can narrow it by serial number, part number or installed equipment. This is not a compliance determination. The registry lists only the engine series, so ADs for every Rotax 503 model are included.

## ADs that may apply (OpenAirDocs): 0 in force

### Matched by airframe (Quad City Ultralight CHALLENGER II CWS)

None in force.

### Matched by engine (Rotax 503 series)

None in force.

## Information bulletins (advisory)

None matched.

## NTSB investigations

None matched to N4436A.

## FAA accident and incident reports

None matched to N4436A.

## Service difficulty reports

None filed for this aircraft. Matched to this aircraft by N-number and event date, checked against the reported serial number, make and model.

## STCs that may be installed (OpenAirDocs)

None matched to this aircraft's models.

## Earlier aircraft with N4436A

The FAA can reassign an N-number once a registration is cancelled. These aircraft carried N4436A before.

- [Cancelled 2003-07-15](https://openairdocs.org/deregistered/N4436A-2003-07-15): Low Dave QUICKSILVER MX II, S/N 1527, built 1983. Triennial form not returned. Owner: [Green River Livestock Co](https://openairdocs.org/faa-owner/GREEN%20RIVER%20LIVESTOCK%20CO), [Rock Springs, WY](https://openairdocs.org/faa-place/WY/Rock%20Springs)
- [Cancelled 1965-05-06](https://openairdocs.org/deregistered/N4436A-1965-05-06): Piper PA-22-150, S/N 22-3765. Owner: [Big Four Paving Inc](https://openairdocs.org/faa-owner/BIG%20FOUR%20PAVING%20INC), [Albuquerque, NM](https://openairdocs.org/faa-place/NM/Albuquerque)

## Related

- Other Quad City Ultralight CHALLENGER II CWS aircraft: https://openairdocs.org/model/quad-city-ultralight-challenger-ii-cws/aircraft.md
- The Rotax 503 series engine: https://openairdocs.org/engine/rotax-503-series.md

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