AD 90-20-05

Final rule

90-20-05 CHRISTEN INDUSTRIES, INC: Amendment 39-6741. Docket No. 90-CE-30-AD.

Applicability: Model A-1 (Husky), (Serial Numbers 1001 thru 1125) airplanes, certificated in any category.

Compliance: Required as indicated unless already accomplished.

To prevent failure of the forward seat back, which could result in loss of control of the airplane, accomplish the following:

(a) Within the next 25 hours time-in-service (TIS) after the effective date of this AD, visually inspect both sides of the front seat back for cracks using a 10x glass on the weld area where the diagonal support tube Part Number (P/N) 35039-008 is attached to the back support tube P/N 35034-005.

(1) If no cracks are found, reinspect this welded area at intervals of 25 hours TIS thereafter.

(2) If cracks are found, prior to further flight modify the seat by the installation of the seat reinforcement kit as specified in Christen Industries Inc., Service Bulletin No. 2, dated July 25, 1990.

(b) Within the next 100 hours TIS after the effective date of this AD, unless accomplished per the instructions in paragraph (a) (2) of this AD, modify the airplane by installing the seat reinforcement kit as specified by Christen Industries Inc., Service Bulletin No. 2, dated July 25, 1990. The inspections required by paragraph (a) of this AD are no longer required when the airplane has been modified with the seat reinforcement kit.

(c) Airplanes may be flown in accordance with FAR 21.197 to a location where the AD may be accomplished.

(d) An alternate method of compliance or adjustment of the initial or repetitive compliance times, which provides an equivalent level of safety, may be approved by the Manager, Denver Aircraft Certification Field Office, FAA, Northwest Mountain Region.

NOTE: The request should be forwarded through an FAA Maintenance Inspector, who may add comments and then send it to the Manager, Denver Aircraft Certification Field Office. All persons affected by this directive may obtain copies of the document referred to herein upon request to Christen Industries, Inc., P.O. Box 547, Afton, Wyoming 83110, Telephone (307) 886- 3151, or may examine this document at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

This amendment (39-6741, AD 90-20-05) becomes effective on October 15, 1990.