85-16-09 PILATUS AIRCRAFT, LTD., AND FAIRCHILD-HILLER: Amendment 39-5107. Applies to Model(s) PC-6 (S/N 1 to and including 844, and S/N 2001 to and including 2092) airplanes certificated in any category.
NOTE: Service Bulletin (S/N) Numbers (no.) 142, 143, and 144 all dated December 1984, are applicable to Pilatus Aircraft Ltd., built airplanes which are identified by Serial Numbers (S/N) below 1000, and Service Letters (S/L) PC6-55-2, PC6-55-3 and PC6-55-4 all dated April 9, 1985, are applicable to Fairchild-Hiller built airplanes which are identified by S/N's above 2000.
Compliance: Required as indicated after the effective date of this AD, unless already accomplished.
To prevent a possible loss of airplane control, accomplish the following:
(a) Within the next 25 hours time-in-service (TIS) after the effective date of this AD:
(1) On airplanes S/N 1 to and including 826 and 2001 to and including 2092 (except 524, 676, 707, 710 and 816), perform the required inspection and corrective action if needed in accordance with paragraphs (b), (c) and (d) of this AD, and
(2) On airplanes S/N 827 to and including 844 perform the required inspection and corrective action if needed in accordance with paragraph (d) of this AD.
(b) Using a dye penetrant test method, inspect the Left Hand and Right Hand cap angles adjacent to the rudder hinge attachment points on the vertical stabilizer for cracks, in accordance with S/B No. 142 Section 2, "ACCOMPLISHMENT INSTRUCTIONS", PARAGRAPH (para.) A "INSPECTION" or S/L PC6-55-2.
If cracks are found, prior to further flight replace the defective cap angle and modify the vertical stabilizer in accordance with S/B No. 142, Section 2, "ACCOMPLISHMENT INSTRUCTIONS" para. B "MODIFICATION", or S/L PC6-55-2.
(c) Using a dye penetrant test method inspect the upper and lower cap angles adjacent to the elevator bearing bracket attachment points on the horizontal stabilizer in accordance with S/B No. 143, Section 2 "ACCOMPLISHMENT INSTRUCTIONS", para. A "INSPECTION", or S/L PC6-55-3.
(1) If cracks are found, prior to further flight, repair in accordance with the repair scheme of S/B No. 143 or S/L PC6-55-3, and in addition;
(2) If the bolt hole is less than 0.120 inches (in.) (3mm) from the edge of the cap angle, modify the horizontal stabilizer prior to further flight in accordance with S/B No. 143, Section 2 "ACCOMPLISHMENT INSTRUCTIONS", para. B "MODIFICATION" or S/L PC6-55-3.
(d) Visually inspect the area around the rectangular cutout located in the front spar of the horizontal stabilizer, adjacent to the elevator control cables pulley assembly, in accordance with S/B No. 144, Section 2 "ACCOMPLISHMENT OF INSTRUCTIONS", para. B "CRACK INSPECTION", or S/L PC6-55-4. If cracks are found and;
(1) If no crack is longer than 0.20 inches (5mm) install within the next 50 hours TIS standard repair plate (P/N 113.45.06.027) in accordance with S/B No. 144, Section 2 "ACCOMPLISHMENT INSTRUCTIONS", para. D "INSTALLATION OF STANDARD REPAIR PLATE" or S/L PC6-55-4.
(2) If any crack is longer than 0.20 inches (5mm) but less than 0.80 inches (20mm), prior to further flight install standard repair plate (P/N 113.45.06.027) in accordance with para. (d)(1) of this AD.
(3) If any crack is longer than 0.80 inches (20mm), prior to further flight repair the horizontal stabilizer in accordance with S/B No. 144, Section 2 "ACCOMPLISHMENT INSTRUCTIONS", para. C "SPECIAL PROCEDURES" or S/L PC6-55-4.
(e) Each 100 hours TIS after the initial inspection:
(1) On airplanes S/N 1 to and including 826 and 2001 to and including 2092 (except 524, 676, 707, 710 and 816) repeat the inspection required by para. (b) of this AD, until the modification described in S/B No. 142, para. 2.B "MODIFICATION" or S/L PC6-55-2 is complied with, at which time this repetitive inspection is no longer required.
(2) On airplanes S/N 1 to and including 844 and S/N 2001 to and including 2092, repeat the inspection required by para. (d) of this AD.
(f) The intervals between the repetitive 100 hour TIS inspections required by para. (e) of this AD may be adjusted up to 10 percent of the specified interval to allow accomplishment of these inspections concurrent with other scheduled maintenance of the airplane.
(g) Aircraft may be flown in accordance with Federal Aviation Regulation 21.197 to a location where this AD can be accomplished.
(h) An equivalent method of compliance with this AD, if used, must be approved by the Manager, Aircraft Certification Staff, AEU-100, Europe, Africa, and Middle East Office, FAA, c/o American Embassy, 1000 Brussels, Belgium.
All persons affected by this directive may obtain copies of the documents referred to herein upon request to Pilatus Aircraft, Ltd., CH6370-Stans, Switzerland, or Fairchild-Republic Corp., Showalter Road, Hagerstown, Maryland 21740, or FAA, Office of the Regional Counsel, Room 1558, 601 East 12th Street, Kansas City, Missouri64106.
This amendment becomes effective on August 31, 1985.