STC SA3988SW-D

United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate Number SA 3988 SW-D This certificate issued to: American Airlines, Inc.

P. O. Box 582809, MD 176 Tulsa, Oklahoma 74158-2809 Certifies that the change in the type design for the following product with the limitations and conditions therefor as specified hereon meels the airvorthiness requivements of Part 25 of the Federal Aviation Regulations.

Original Product -Type Certificate Number: AGWE Маке: McDonnell Douglas Model: DC9-82/-83 Description of Type Design Change:

Modify the cabin pressurization low flow annunciator system by connecting the low flow signal to the Master Caution Annunciator in accordance with American Airlines Engineering Change Order K1975XX, dated January 6, 1997, or later DAS1SW approved revision Limitations and Conditions:

This approval should not be incorporated in any aircraft of this specific model until compatibility of this modification with other previously approved modifications has been determined by the installer.

r of the Federal Aviation Administration .

Date of Application: December 9, 1996 Jute missed:

Date of Issuance: February 28, 1997 Jale umended:

FEDERAL AVIATION E. I. Grewe ( Signage) TAMIN STRATO DAS1SW Coordinator (Title) 47 FAA FORM 8110-2 (10-68)

TRANSFER ENDORSEMENT Transter the ownership of Supplemental Type Certificate Number to (Name of transferee) (Address of transferee) (Number and street) (City, State, and ZIP code) from (Name of grantor) (Print or type) - (Address of grantor) (Number and street) (City, State, and ZIP code ) Extent of Authority (if licensing agreement):

Date of Transfer: - Signature of grantor (In ink): -