# STC SL898SO - Type: Supplemental type certificate - Status: Current, Reissued - Holder: McGrath Michael D, United States - Description: Modification of Model A50S hot air balloon by adding 2 appendages to the envelope and an additional burner. - Applied: March 31, 1976 - Status date: July 18, 2005 - Product: Aircraft, Balloon - Certification basis: Part 21 - Data sheets: [TCDS A15SO](https://openairdocs.org/tcds/A15SO) - Certificate PDF: https://openairdocs.org/files/sha256/48/df/48dfed37b92fc5c7289e69864c211546bad142509f948e011658bd672951d99e - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/E01FEFE41A877B96862570F2005C45AB.0001 - DRS record last changed: December 6, 2025 - Page: https://openairdocs.org/stc/SL898SO ## ADs that name it (0) None. ## Approved models (1) - McNeely Sr. John A. A50S ([TCDS A15SO](https://openairdocs.org/tcds/A15SO)) ## What the certificate says This is OCR from the scanned FAA certificate. OCR can misread letters and numbers. United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate Number S189850 Reissued on July 18, 2005 to supersede the original STC which has been lost or misplaced. This certificate issued to: Michael D. McGrath. 8502 Wium Road Cary, Illinois 60013 Part 31 of the Federal Aviation Rogulations. Original Product -- Typs Certifioato Number: A1550 Make: Micheal D. Adams Model: A505 Description of Type Design Change: Modification of Model ASOS Hot Air Balloon by adding two appendages to the envelope and an additional burner in accordance with Michael D. Adams Drawing List Model AS0S-C, dated May 10, 1976, or latest FAA approved revision. Limitations and Conditions: The approval of this change applies to Michael D. Adams Model ASOS Hot Air Balloons only. This approval should not be extended to other airplanes of this model on which other previously approved modifications are incorporated unless it is determined by the installer that the interrelationship between this change and any of those other previously approved modifications will produce no adverse effect upon the airworthiness of that balloon. Model ASOS-C Balloon Flight Manual, dated May 10, 1976, is a required part of this STC. Model A5OS Balloon Flight Manual, dated December 23, 1974, is no longer required for balloons modified in accordance with this STC. Date of Application: March 31, 1976 Dato moissued: October 31, 1985, March 15, 1989 Date of Issuance: May 10, 1976 July 18, 2005; July 30, 2005 reissued to Michael D. McGrath Dato am nded: January 11, 1977 FEDERAL AVIATION Bey dircotipon of the Aaps (Signature) TOMNISTRATIO Manager Small Aircraft Certification Office ## Every issue (1) - July 18, 2005: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/48/df/48dfed37b92fc5c7289e69864c211546bad142509f948e011658bd672951d99e) --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.