# STC ST09972SC

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: Liebherr Aerospace Saline Co., United States
- Description: Installation of an air humidifier system in the Cockpit Environmental Control System.
- Applied: October 5, 1999
- Status date: July 2, 2007
- Product: Aircraft, Large Multi-Engine
- Certification basis: Part 21, Part 25
- Data sheets: [TCDS A20WE](https://openairdocs.org/tcds/A20WE)
- Certificate PDF: https://openairdocs.org/files/sha256/e5/db/e5db8499c0346b12cc4d8acf5991cefcb145d6eac75035f1eb92c3418c2a2daa
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/900618EBDF6D1E378625737C00673DCF.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/ST09972SC

## ADs that name it (0)

None.

## Approved models (1)

- The Boeing Company 747-400 Series ([TCDS A20WE](https://openairdocs.org/tcds/A20WE))

## 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.

1465 Woodland Drive Saline, MI 48176

Part 25 of the Federal Aviation Regulations. ( See Type Certificate Data Sheet A20WE for complete Certification Basis).

Original Product--Type Certificate Number : A20WE Make : Boeing Model : 747-400 Series Description of Type Design Change:

Installation of an Air Humidifier System in the Cockpit Environmental Control System in accordance with the Le Bozec Documents:

1. Master Document List, Document Number TDL4217R25-00, Revision A, dated January 4, 2002, or later FAA approved revision,

2. Airplane Flight Manual Supplement, Document Number FMS4217R25-00, Revision IR, dated January 15, 2002, or later FAA approved revision,

3. Airplane Flight Manual Supplement, Document Number FMS4217R25-01, Revision IR, dated January 15, 2002, or later FAA approved revision, and

4. Instructions for Continued Airworthiness, Document Number ICA4217R25-00, Revision IR, dated April 20, 2000, or later FAA approved revision.

1. Compatibility of this design change with previously approved modifications must be determined by the installer.

2. 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 : October 5, 1999

Date of issuance : January 15, 2002 Date reissued : September 23, 2005, July 2, 2007

( Signature) Charles L. Smalley Manager, Systems and Flight Test Branch Chicago Aircraft Certification Office

( Title)

## Every issue (2)

- July 2, 2007: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/e5/db/e5db8499c0346b12cc4d8acf5991cefcb145d6eac75035f1eb92c3418c2a2daa)
- September 23, 2005: Reissued, Historical. [certificate](https://openairdocs.org/files/sha256/ec/95/ec95f14ed4ac41008fabd1d6c5be96dc17e7b581d8a03a967f657aab6e7e8480)

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