89-04-07 CANADAIR: Amendment 39-6141.
Applicability: Model CL-44D4 and CL-44J series airplanes, certificated in any category.
Compliance: Required as indicated, unless previously accomplished.
To prevent wing failure due to exfoliation corrosion on the wing upper skin, accomplish the following:
A. Within 225 hours time-in-service or 30 days after the effective date of this AD, whichever occurs first, and thereafter at intervals not to exceed 12 months, perform a visual inspection of the upper wing skin area between the front and rear spars over the total wing span for corrosion, including raised blistering or bulging, in accordance with Canadair Alert Wire 44T-1340/2431, dated October 28, 1988.
1. If the extent of such corrosion exceeds 20 sq.in. in any one skin panel, between chordwise joints, prior to further flight conduct a non-destructive testing (NDT) inspection, using ultrasonic or eddy current inspection techniques, to determine the skin thickness,in accordance with the Alert Wire. Repair the corrosion area prior to further flight, in accordance with a method approved by the Manager, New York Aircraft Certification Office, FAA, New England Region.
2. If the extent of such corrosion exists within an area equal to or less than 20 sq.in. in any one skin panel, between chordwise joints, repair corrosion area within 900 hours time-in-service or 6 months after the effective date of this AD, whichever occurs first. Repair must be accomplished in accordance with a method approved by the Manager, New York Aircraft Certification Office, FAA, New England Region.
B. Within 48 hours after performing the inspections required by paragraph A., above, submit a report of results to Canadair, in accordance with Canadair Alert Wire 44T- 1340/2431, dated October 28, 1988. The report must include information as to the extent and location of the corrosion, and the inspection method used.
C. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, New York Aircraft Certification Office, FAA, New England Region.
NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who may add any comments and then send it to the Manager, New York Aircraft Certification Office.
D. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.
All persons affected by this directive who have not already received the appropriate service information from the manufacturer may obtain copies upon request to Bombardier, Inc., Canadair Aerospace Group, P.O. Box 6087, Station A, Montreal, Quebec H3C 3G9, Canada. This information may be examined at FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or FAA, New England Region, New York Aircraft Certification Office, 181 South Franklin Avenue, Room 202, Valley Stream, New York.
This amendment (39-6141, AD 89-04-07) becomes effective March 7, 1989.