AD 89-08-01

89-08-01 McDONNELL DOUGLAS: Amendment 39-6178.

Applicability: Model DC-8 series airplanes, equipped with control columns, P/N 5614272-1 and/or -2, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To prevent the loss of airplane control in critical flight regimes due to fatigue failure of the control column, accomplish the following:

A. Within the next 1,250 hours time-in-service after September 25, 1974 (the effective date of Amendment 39-1967), unless already accomplished within the last 1,250 hours time-in-service, and thereafter at intervals not to exceed 2,500 hours time-in-service, except as provided below, conduct a dye penetrant or eddy current inspection of the control columns in accordance with the instructions in McDonnell Douglas All Operators Letter 8-632, issued October 11, 1972, or equivalent inspection technique approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region.

1. If surface indications of cracking exist, consisting of small specks not yet joined to form a linear crack of at least 1/8-inch in length, no rework is required, but the inspection interval is thereafter reduced to 2,000 hours time-in-service.

2. If linear cracks of 1/8-inch or more exist, blendout may be accomplished, in lieu of replacement, subject to the following qualifications: Blendout shall not exceed .030-inch in depth from the original surface and shall be blended over an area 10 times the depth. The defect shall not exceed an initial length of 1/4-inch. No more than two defects can occur in the same horizontal plane, and the defects shall be separated by at least 2-inch center-to-center spacing. Additional defects may be blended if the vertical distance between horizontal planes is at least 1/4-inch and the 2-inch center-to-center spacing requirement in the same horizontal plane is observed. After this rework, inspect at intervals not to exceed 2,500 hours time-in-service.

3. If cracks which exceed the limits described in paragraph A.2 of this AD are discovered as a result of any inspection, remove and replace the control columns, P/N's 5614272-1 and/or -2, in accordance with paragraph C. of this AD, or rework in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region.

B. Within the next 1,250 hours time-in-service after the effective date of this AD, unless already accomplished within the last 1,250 hours time-in-service, conduct a dye penetrant or eddy current inspection of the control columns, in accordance with the instructions in McDonnell Douglas DC-8 Alert Service Bulletin A27-267, dated February 18, 1987, Revision 1, dated May 22, 1987, or Revision 2, dated February 14, 1989, or equivalent inspection technique approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region.

1. If no cracks are found, accomplish repetitive inspections at intervals not to exceed 2,500 hours time-in-service.

2. If cracks are found, prior to further flight, remove and replace the control column in accordance with paragraph C. of this AD.

Accomplishment of the provisions of paragraph B., constitutes terminating action for the inspection requirements of paragraph A. of this AD. However, for areas specified in the McDonnell Douglas All Operators Letter 8-632, dated October 11, 1972, allowable limits and blendout criteria established in accordance with paragraph A. of this AD still apply.

C. Replacement of both pilot's and copilot's control columns, P/N's 5614272-1 or 5614272-2, respectively, with new control columns, SB 09270288-3, 5614272-501, or -503 (pilot's), and SB 09270288-4, 5614272-502, or -504 (co-pilot's), in accordance with McDonnell Douglas DC-8 Service Bulletin 27-267, issued January 20, 1988, or Revision 1, dated February 17, 1989, constitutes terminating action for the requirements of this AD.

D. 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, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain 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, Los Angeles Aircraft Certification Office.

E. 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 documents from the manufacturer may obtain copies upon request to McDonnell Douglas Corporation, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Director of Publications, C1-LOO (54-60). These documents may be examined at the FAA, NorthwestMountain Region, 17900 Pacific Highway South, Seattle, Washington, or at 3229 E. Spring Street, Long Beach, California.

This amendment supersedes AD 73-07-09, (Amendment 39-1967) which was effective on September 25, 1974.

This amendment (39-6178, AD 89-08-01) becomes effective May 2, 1989.