AD 88-14-03 ACTIVE

88-14-03 BOEING HELICOPTER COMPANY (BOEING VERTOL; VERTOL) AND KAWASAKI HEAVY INDUSTRIES, LTD: Amendment 39-5962. Applies to Boeing Helicopter Model 107-II and Kawasaki Model KV107-II and KV107-IIA helicopters certificated in any category. (Docket No. 88-ASW-28)

Compliance is required as indicated, unless already accomplished.

To prevent failure of a main rotor hub, P/N 107R2550, which could result in loss of control of the helicopter accomplish the following:

(a) Within the next 10 hours' time in service (TIS) after the effective date of this AD, unless accomplished within the last 40 hours TIS, or before the accumulation of 1,200 hours TIS, whichever comes later, gain access to the forward and aft main rotor hubs, remove paint from the lower surface on both forward and aft center hubs, and conduct an inspection of the lower plate area of the forward and aft main rotor hubs for cracks as follows:

(1) Conduct an eddy current inspection of the lower plate surface.

(i) Direct particular attention to the transition radius between the lag lug and lower plate,

(ii) Replace cracked hubs with serviceable parts.

(2) If eddy current facilities are not available, conduct a dye penetrant inspection of the lower plate surface.

(i) Apply dye penetrant to the lower plate surface.

(ii) Allow 5 to 15 minutes of dwell time for dye penetration before removal.

(iii) Remove excess penetrant.

(iv) Apply the developer to the lower plate surface.

(v) Allow 5 to 15 minutes of drying time for the developer.

(vi) Visually inspect the developed areas for cracks (dye bleed through).

(vii) Direct particular attention to the transition radius between the lag lug and lower plate.

(viii) Clean surface to remove penetrant and developer from hubs.

(ix) After cleaning, reinspect the transition radius using a 7X power (or greater) magnifying glass.

(x) Replace cracked hubs with serviceable parts.

Note: Do not paint the lower surface of the forward and aft center hubs after the inspections. Also, Boeing Helicopter Company Service Bulletin No. 107-372 pertains to this inspection.

(b) Inspect, in accordance with paragraph (a), both the upper and lower plate areas of hubs which have been inverted and moved to the other head.

(c) After the initial inspections of paragraphs (a) and (b), repeat the inspections at intervals not to exceed 50 hours TIS from the last inspection.

(d) Upon submission of substantiating data by an owner or operator through an FAA maintenance inspector, the Manager, New York Aircraft Certification Office, FAA, New England Region, may adjust the compliance times specified in this AD.

(e) An alternate method of compliance which provides an equivalent level of safety with this AD may be used when approved by the Manager, New York Aircraft Certification Office, 181 South Franklin Avenue, Valley Stream, New York 11581.

(f) 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, 39-5962, becomes effective July 5, 1988.