# STC SA551AL

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: Aircraft Innovations, LLC, United States
- Description: Installation of Day & Night 4-1 fiberglass propeller spinner.
- Applied: May 24, 1974
- Status date: September 11, 2009
- Product: Aircraft, Single-Engine
- Certification basis: Part 3, Part 21
- Data sheets: [TCDS 1A2](https://openairdocs.org/tcds/1A2)
- Certificate PDF: https://openairdocs.org/files/sha256/6f/4a/6f4a9d64972216ab86dfb4a4668315aa9e23ae95a1c32c3ba82cb07009b9644c
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/38E82BB5CD8EB5AD86257639005E828B.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA551AL

## ADs that name it (0)

None.

## Approved models (8)

- Piper Aircraft Inc. PA-18-135 ([TCDS 1A2](https://openairdocs.org/tcds/1A2))
- Piper Aircraft Inc. PA-18-150 ([TCDS 1A2](https://openairdocs.org/tcds/1A2))
- Piper Aircraft Inc. PA-18A-135 ([TCDS 1A2](https://openairdocs.org/tcds/1A2))
- Piper Aircraft Inc. PA-18A-150 ([TCDS 1A2](https://openairdocs.org/tcds/1A2))
- Piper Aircraft Inc. PA-18AS-135 ([TCDS 1A2](https://openairdocs.org/tcds/1A2))
- Piper Aircraft Inc. PA-18AS-150 ([TCDS 1A2](https://openairdocs.org/tcds/1A2))
- Piper Aircraft Inc. PA-18S-135 ([TCDS 1A2](https://openairdocs.org/tcds/1A2))
- Piper Aircraft Inc. PA-18S-150 ([TCDS 1A2](https://openairdocs.org/tcds/1A2))

## What the certificate says

Read from the PDF's text layer, without the form's printed wording; the layout is lost and the order can differ. The PDF is the record.

This certificate issued to Aircraft Innovations, LLC PO Box 110164 Anchorage, AK 99511 Part 3 of the Civil Air Regulations.

Original Product — Type Certificate Number: 1A2 Make: Piper Model: PA-18 “135”, PA-18A “135”, PA-18S “135”, PA- 18AS “135”, PA-18 “150”, PA-18A “150”, PA-18S “150, PA-18AS “150”

Description of Type Design Change: Installation of Day & Night, Inc. 4-1 fiberglass propeller spinner which is manufactured and installed per revision A (sheet 1 of 1) of Day & Night, Inc., sealed drawing number 4-1 and pages 1 through 6 of Day & Night, Inc., sealed report “Manufacturing & Installation Instructions for Day & Night, Inc., 4-1 Fiberglass Spinner” dated February 4, 1975.

1. The approval of this change in type design applies basically to Piper models PA-18 “135”, PA-18A “135”, PA-18S “135”, PA-18AS “135”, PA-18 “150”, PA-18A “150”, PA-18S “150, and PA-18AS “150” only. Compatibility of this design change with previously approved modifications must be determined by the installer. This determination should include consideration of significant changes in weight distribution, such as an increase in the fixed disposable weight in the fuselage.

2. The Day & Night, Inc. 4-1 propeller spinner is approved for installation on only those aircraft on which the standard Piper metal propeller spinner (Piper part number 14422-00) is approved.

3. If the holder agrees to permit another person to use this certificate to alter the product, the holder shall give the other person written evidence of that permission.

Date of application: May 24, 1974 Date reissued : May 7, 1979; September 11, 2009

Date of issuance: May 5, 1975 Date amended: September 11, 2009

( Signature) David D. Swartz Acting Manager, Anchorage Aircraft Certification Office

( Title)

## Every issue (2)

- September 11, 2009: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/6f/4a/6f4a9d64972216ab86dfb4a4668315aa9e23ae95a1c32c3ba82cb07009b9644c)
- May 7, 1979: Reissued, Historical. [certificate](https://openairdocs.org/files/sha256/05/c1/05c12b5e556fcd9db5ec0d2b5bdf8811c153e0e7ad4afef9c6ff8b00a601a8c8)

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