Airworthiness Directive · Amendment 39-21174 · Main rotor drive system
PZL Swidnik S.A. Helicopters
This AD applies to PZL Swidnik S.A. (PZL) Model PZL W-3A helicopters, certificated in any category, with a main rotor (M/R) vibration absorber star part number (P/N) 30.23.005.01.04 installed.
The FAA is adopting a new airworthiness directive (AD) for PZL Swidnik S.A. Model PZL W-3A helicopters. This AD requires repetitively inspecting the main rotor (M/R) vibration absorber star and depending on the inspection outcome, performing more in-depth inspections and repairing, replacing, or removing the vibration absorber star from service. This AD was prompted by a report of corrosion detected on an M/R vibration absorber star. The actions of this AD are intended to address an unsafe condition on these products.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
For helicopters with a serial number (S/N) up to 37.10.12 inclusive, within 25 hours time-in-service (TIS) or 15 days, whichever occurs first; and for helicopters with an S/N above 37.10.12, within 300 hours TIS or 12 months after the date of manufacture, whichever occurs first:
(1) Access the M/R vibration absorber by following Attachment 1, Procedure—Removal, Inspection, Repair, and Installation of Vibration Absorber Star, section II., of WYTWORNIA SPRZĘTU KOMUNIKACYJNEGO “PZL-Swidnik” Spolka Akcyjna Mandatory Bulletin No. BO-37-18-291, dated March 13, 2018 (MB BO-37-18-291 Attachment 1).
(i) Clean the M/R vibration absorber star surface. Visually inspect the M/R vibration absorber star for paint coating delamination, blistering, discoloration, and missing paint coating, a scratch, a dent, a nick, and corrosion.
(ii) If there is any paint coating delamination, blistering, or discoloration, or missing paint, any scratch, any dent, any nick, or corrosion, before further flight, mechanically remove any remaining paint coating and inspect the M/R vibration absorber star for a scratch, a dent, a nick, and corrosion. Additionally, inspect the heads of each bolt P/N 30.23.000.08.04 that secures the vibration absorber star to the bracket for corrosion under the bolt heads.
Note 1 to paragraph (e)(1)(ii) of this AD: the anodic coating may become damaged while removing the paint coating.
(A) If there is no scratch, dent, nick, or corrosion on the M/R vibration absorber star, before further flight, repair the paint coating.
(B) If there is a scratch, a dent, a nick, or corrosion on the M/R vibration absorber star not exceeding the accumulated maximum total polishing depth of 0.5 mm, using 80-100 grit abrasive paper or an equivalent grit file or scraper, polish out any scratch, dent, nick, and corrosion and do the following:
(1) Using 150-180 grit abrasive paper, blend the repaired surface and make a smooth chamfer as shown in Sketch 2. Blending Method, MB BO-37-18-291 Attachment 1. The blending width “S” must be at least 10 times greater than blending depth “h.” The radii “R1” and “R2” must be at least 5 times greater than depth “h.”
(2) Using 600-900 grit abrasive paper, polish the repaired surface and repair the paint coating.
(C) If there is a scratch, a dent, a nick, or corrosion on the M/R vibration absorber star that meets or exceeds the accumulated maximum total polishing depth of 0.5 mm, before further flight, remove from service the M/R vibration absorber star.
(D) If there is corrosion on the head of any bolt P/N 30.23.000.08.04 that secures the vibration absorber star to the bracket, before further flight, repair or replace the M/R vibration absorber star in accordance with FAA approved procedures.
(2) Thereafter, at intervals not to exceed 300 hours TIS or 1 year, whichever occurs first, perform the actions required by paragraph (e)(1) of this AD.
(3) After the effective date of this AD, do not install an M/R vibration absorber star on any helicopter unless the requirements of paragraph (e)(1) of this AD have been accomplished.
