# N21SX: 1993 Luebke Ralph C STD CLS AMER SPIRIT

- Status: Valid registration
- Airframe: [Luebke Ralph C STD CLS AMER SPIRIT](https://openairdocs.org/model/luebke-ralph-c-std-cls-amer-spirit) (registry code 05624ND, 1 seats)
- Engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000)
- Serial number: 11
- Year built: 1993
- Type: Glider
- Engine type: None
- Airworthiness: Experimental, amateur built
- Airworthiness date: April 16, 1999
- Certificate issued: September 4, 2018
- Expires: September 30, 2028
- Mode S code: A1B8CF
- Registered owner: [Cantwell Paul M](https://openairdocs.org/faa-owner/CANTWELL%20PAUL%20M)
- Location: [Momence, IL](https://openairdocs.org/faa-place/IL/Momence)
- Owner type: Individual
- Owner's area on the map: 41.1477° N, 87.6225° W: Placed by OpenAirDocs at the center of ZIP code 60954, within about 5 miles (OpenAirDocs). The owner's mailing address, not where the aircraft is based
- FAA registry: https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=21SX
- Page: https://openairdocs.org/aircraft/N21SX

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.

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

### Matched by airframe (Luebke Ralph C STD CLS AMER SPIRIT)

None in force.

### Matched by engine (NONE)

None in force.

## Information bulletins (advisory)

None matched.

## NTSB investigations

None matched to N21SX.

## NTSB investigations on N21SX not matched to an aircraft (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB ATL90LA168](https://openairdocs.org/ntsb/ATL90LA168), Sep 7, 1990: Schleicher ASK-21 (N21SX), Memphis, TN, substantial damage. Probable cause: AN INFLIGHT COLLISION WITH A TREE DUE TO MISJUDGING HIS GLIDEPATH.

## FAA accident and incident reports

None matched to N21SX.

## Reports on N21SX not matched to an aircraft (1)

They name N21SX, but no registry record covers the date, the aircraft registered then was built later, or the report describes another aircraft.

- [Accident 19900907038499A](https://openairdocs.org/incident/19900907038499A), Sep 7, 1990: Schler ASK21 (N21SX), Memphis, TN, Substantial damage. Ran out of lift. Struck tree on off airport landing.

## 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.

## Related

- Other Luebke Ralph C STD CLS AMER SPIRIT aircraft: https://openairdocs.org/model/luebke-ralph-c-std-cls-amer-spirit/aircraft.md
- The NONE engine: https://openairdocs.org/engine/none.md

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