AD 90-06-10

90-06-10 SCHWEIZER AIRCRAFT CORPORATION: Amendment 39-6529. Docket No. 88-ASW-37.

Applicability: All Schweizer Model 269A, 269A-1, 269B, and 269C helicopters, certificated in any category, with Serial Numbers 0004 through 0819 and those subsequent to 0819, which have had throttle cables replaced.

Compliance: Required as indicated, unless already accomplished.

To prevent loss of throttle control, accomplish the following:

(a) Within the next 25 hours' time in service or within 30 days, whichever occurs first after the effective date of this AD, identify, inspect, and replace as indicated, the throttle cable assembly as follows:

(1) Determine if aluminum fittings are installed as follows:

(i) Check both end fittings of the cable assembly with a magnet to determine whether they are magnetic. Cables which incorporate magnetic fittings (magnet adheres to fitting) do not require the hardness test specified by paragraph (a)(1)(ii) below. For these cableassemblies, omit step (a)(1)(ii), and continue inspection with step (a)(2) below.

(ii) If the magnet does not adhere to the fitting, perform a hardness test on the fitting. If Rockwell hardness is less than B-85, remove and replace the cable assembly with a swaged steel cable assembly in accordance with paragraph (c) of this AD before further flight. Performance of the hardness test will require removal of the throttle cable assembly from the helicopter in accordance with standard maintenance instructions.

(2) Visually check both ends of the cable to determine whether the cable incorporates swaged or threaded steel end fittings.

NOTE: Throttle cables which incorporate swaged end fittings may be identified by six evenly spaced flat spots around the barrel of the fitting just behind the lug. Threaded end fittings incorporate a cylindrical barrel (no flat spots).

(3) If the cable incorporates swaged steel end fittings (as determined from steps (a)(1) and (2) above), further compliance is not required except to record compliance in the helicopter log book as "THROTTLE CABLE WITH SWAGED STEEL END FITTINGS INSTALLED."

(4) If cable incorporates a threaded steel end fitting (as determined from steps (a)(1) and (2) above), perform an inspection before further flight and perform repetitive daily inspections in accordance with paragraph (b) of this AD until the cable is replaced in accordance with paragraph (c) of this AD.

(5) Record compliance with paragraph (a) of this AD in the compliance record of the helicopter log book.

(b) Prior to the first flight of each day, conduct a visual check of throttle cable assemblies with threaded steel end fittings as follows:

(1) Inspect cable end fittings for general condition and security of attachment. If any abnormality or damage is noted, replace cable assembly in accordance with paragraph (c) of this AD.

(2) Using a flashlight, visually inspect cable push rod for exposed threads adjacent to end fitting (both ends of cable assembly).

NOTE: The cable push rod is the moveable rod that is attached directly to the cable end fitting (lug).

(3) If threads are visible, replace cable assembly before further flight in accordance with paragraph (c) of this AD.

(4) Record compliance with paragraph (b) of this AD in the compliance record of the helicopter log book.

(c) Within the next 400 hours' time in service from the effective date of this AD, or within 12 months, whichever occurs first, replace with swaged steel end fittings all threaded steel end fittings which were not replaced during the inspections and rework required by paragraphs (a) and (b) of this AD. Replacement parts applicability is as follows:

Model Swaged Steel Cable Assembly Part Numbers (P/N) 269A 269A4683-9 269A-1 269A4683-9 269B 269A4683-7 269C 269A4683-7

(1) Remove throttle control cable (reference Basic Helicopter Maintenance Instructions (HMI), paragraph 4-11). Donot bend throttle cable support tubes more than 8 degrees from centerline of cable; doing so could cause deformation of the support tubes, premature failure of the cable, and loss of throttle control.

NOTE: The cable support tube is the stationary cylinder on the end of the cable through which the cable push rod slides.

(2) Install P/N 269A4683-7 or -9 throttle control cable assembly (reference Basic HMI, paragraph 4-11).

(3) Rig throttle control (reference Basic HMI).

(4) Check idle speed and idle mixture in accordance with appropriate maintenance instructions, and adjust as required. Installation of the upgraded cable assembly, P/N 269A4683-7 or -9, cancels the repetitive inspection required by paragraph (b) of this AD.

(5) Record compliance with paragraph (c) of this AD in the compliance record and in the maintenance record of the helicopter log book.

NOTE: The instructions in this AD are similar to those contained in Schweizer SIN N-210, dated April15, 1988.

An alternate method of compliance which provides an equivalent level of safety with this AD may be used upon the submission of substantiating data by an owner or operator through an FAA Maintenance Inspector, when approved by the Manager, New York Aircraft Certification Office, 181 South Franklin Avenue, Valley Stream, New York 11581.

(e) In accordance with FAR Sections 21.197 and 21.199, flight is permitted to a base where the requirements of this AD may be accomplished.

This amendment (39-6529, AD 90-06-10) becomes effective on April 6, 1990.