SAIB ACE-96-04 —

No. ACE-96-04 August 7, 1996

Published by: FAA, AFS-610, P.O. Box 26460, Oklahoma City, OK 73125 This is issued for informational purposes only and any recommendation for corrective action is not mandatory.

INTRODUCTION: The purpose of this Special Airworthiness Information Bulletin is to advise owners/operators of The New Piper Aircraft, Inc. (Piper) PA-18-150 (Super Cub) of the need to comply with Service Bulletin (SB) 966, dated January 21, 1994.

BACKGROUND: Issuance of SB 966 was prompted by reports from the field that some aircraft showed evidence of premature internal corrosion in the steel tube structure of the vertical fin and the five tail surfaces (stabilizers, elevators, and rudder). The manufacturing process employed for these aircraft and the service history from the field were reviewed, and analysis of the corroded areas indicates that over time the integrity of the structure will be compromised.

Part I of SB 966 addresses replacement of the tail surfaces on the following serial numbered aircraft:

1809002; 1809004 through 1809011; 1809013 through 1809032; 1809034

through 1809038; 1809043 through 1809045; 1809047; and 1809050 through

1809052.

Part II of SB 966 requires the complete sealing of the forward and aft tubes of the vertical fin (leading edge and tail posts) on the following serial numbered aircraft:

1809001 through 1809011; 1809013 through 1809032; 1809034 through

1809038; 1809043 through 1809045; 1809047; 1809050 through 1809052; and

1809054.

RECOMMENDATIONS: Routine visual inspections of the tail surface structure will yield some information as to when the replacement should be accomplished. In addition, the internal condition of a portion of the tubular structure may be determined with the use of a boroscope instrument. Should any corrosion be detected, it is recommended that replacement of the tail surfaces be immediately accomplished.

In addition, variance in the timeframe to replace the tail surfaces may be based on the aircraft’s storage history and/or geographical location(s). Similarly, it may be permissible to minimize the aircraft “down time” if compliance with the SB is performed in conjunction with the recovering of the aircraft.

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The Federal Aviation Administration is continuing to monitor the compliance status and service history and may elect to mandate compliance with the SB by the initiation of an Airworthiness Directive (AD) in the future.

A copy of SB 966 may be obtained from:

The New Piper Aircraft, Inc.

Attn: Customer Service

2926 Piper Drive

Vero Beach, FL 32960

FOR FURTHER INFORMATION CONTACT: Christina Marsh, Aerospace Engineer, FAA, Atlanta Aircraft Certification Office, Campus Building, 1701 Columbia Avenue, Suite 2-160, College Park, Georgia 30337-2748; telephone (404) 305-7362; facsimile (404) 305-7348.