90-15-18 BEECH: Amendment 39-6667. Docket No. 90-CE-13-AD.
Applicability: Models 99, 99A, and A99A (Serial Numbers (S/N) U-1 through U-147, except U-146); and B99 (S/N U-146 through U-151, except U-147) airplanes certified in any category.
Compliance: Required as indicated after the effective date of this AD, unless already accomplished.
To prevent loss of structural integrity in the vertical stabilizer (fin) main spar, accomplish the following:
(a) For airplanes that have accumulated 2,000 or more hours TIS on the effective date of this AD, within the next 50 hours TIS, unless already accomplished within the last 450 hours TIS per AD 73-03-04, and thereafter at intervals not to exceed 500 hours TIS, visually inspect utilizing a three to five power magnifying glass the vertical fin main spar at each side of the bend location for cracks or nicks as shown in Figure 3 of Beechcraft Service Instructions No. 0530-134, Revision 1, dated June 1975.
(b) If, during any inspection required herein, a crack that does not exceed 0.25 inches in length is found in either a spar flange or in an angle doubler, and no such cracks are found in both members on the same side, prior to further flight either:
(1) Repair the spar by installing a plate doubler in accordance with Beechcraft Service Instructions No. 0530-134, Revision 1, dated June 1975, and reinspect at 500 hour intervals thereafter per Paragraph (a); or
(2) Replace the spar with an equivalent airworthy part and reinspect per the requirements of this AD.
(c) If, during any inspection required herein, a crack is found in both the spar flange and angle doubler flange on the same side, or if a crack exceeds 0.25 inch in length, prior to further flight replace the vertical fin assembly with a Part Number (P/N) 115-640000-605 or -607 or -651 vertical fin.
(d) Within the next 500 hours TIS after the effective date of this AD, or upon the accumulation of 20,000 hours TIS on theoriginal vertical stabilizer, whichever occurs later, either:
(1) Replace the vertical fin with a serviceable P/N 115-640000-605 or -607 or -651 vertical fin; or
(2) Verify that no cracks have ever been detected in the affected structure and install a plate doubler per Beechcraft Service Instructions No. 0530-134, Rev. 1, dated June 1975.
(e) The inspections specified in Paragraph (a) of this AD are no longer required in a P/N 115-640000-605 or -607 or -651 vertical fin or if a plate doubler per Paragraph (d)(2) above has been installed. A doubler installed over previously cracked structure does not comply with this paragraph.
(f) Airplanes may be flown in accordance with FAR 21.197 to a location where this AD can be accomplished.
(g) 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, Wichita Aircraft Certification Office, FAA, 1801 Airport Road, Room 100, Wichita, Kansas 67209.
NOTE: The request should be forwarded through an FAA Maintenance Inspector, who may add comments and send it to the Manager, Wichita Aircraft Certification Office.
All persons affected by this directive may obtain copies of the document referred to herein upon request to the Beech Aircraft Corporation, Commercial Service, Department 52, P.O. Box 85, Wichita, Kansas 67201-0085; or may examine this document at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 East 12th Street, Kansas City, Missouri 64106.
This AD supersedes AD 73-03-04, Amendment 39-3695.
This amendment (39-6667, AD 90-15-18) becomes effective on September 11, 1990.