AD 95-13-11 R1

On June 22, 1995, the FAA issued AD 95-13-11, amendment 39-9291 (60 FR 35326, July 7, 1995), which is applicable to certain McDonnell Douglas Model DC-10-10 airplanes. That AD requires repetitive eddy current test high frequency (ETHF) surface inspections to detect fatigue cracking, and repair of the upper cap in the front spar of the wing if any cracking is found. That AD also requires additional repetitive inspections after any repair of the upper cap. Additionally, that AD stipulates that, if the preventive modification is installed on an airplane on which no cracks are found during the initial inspection, the repetitive inspections may be terminated. That action was prompted by reports of fatigue cracking in the upper cap of the front spar of the wing in the forward flange area. The actions required by that AD are intended to prevent progression of fatigue cracking, which could cause reduced structural integrity of the wing front spar and damage toadjacent structures.

Since the issuance of that AD, the FAA has received communications from affected operators that the area defined for the ETHF surface inspection is unclear. Specifically, these operators have indicated that the referenced McDonnell Douglas DC-10 Service Bulletin 57-129, dated August 12, 1994, recommends inspection of the upper cap of the front spar of the left and right wing "between" stations Xos 667.678 and Xos 789.645 in certain paragraphs but describes the inspection "at" stations Xos 667.678 and Xos 789.645 in the accomplishment instructions. AD 95-13-11 requires inspection "between" stations Xos 667.678 and Xos 789.645.

These operators have therefore, requested that the FAA clarify the AD to indicate exactly what area is required to be inspected.

In considering this request, and upon further review of the wording of the current AD, the FAA concurs that some clarification is necessary.

It was the FAA's intent that the requirements of AD 95-13-11 be parallel to those actions recommended by the manufacturer in the accomplishment instructions of its referenced service bulletin. The intended requirements of the AD were that affected operators would conduct the ETHF inspections to detect fatigue cracks at the areas where cracking had been reported, namely at stations Xos 667.678 and Xos 789.645. However, as AD 95-13-11 is currently worded, operators may incorrectly conduct ETHF inspections "between" these stations, rather than "at" those stations. Such misunderstanding could result in operators unnecessarily conducting ETHF inspections at other stations, which would be of no significant safety value and would entail incurring needless additional costs in labor and downtime.

Operators should note that the economic information supplied in the preamble of AD 95-13-11 remains unchanged since that information was based on the workhours required to perform the ETHF inspection at stations Xos 667.678 and Xos 789.645, in accordance with data supplied in McDonnell Douglas Service Bulletin 57-129, dated August 12, 1994.

Since it is obvious that the required ETHF inspection area is not totally clear in the way that AD 95-13-11 is currently worded, the FAA has determined that the wording of paragraph (a) of the AD must be revised to clarify the intent of the required actions. This action revises that paragraph to specify that the inspection area is at stations Xos 667.678 and Xos 789.645.

Action is taken herein to clarify these requirements of AD 95-13-11 and to correctly add the AD as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13).

The final rule is being reprinted in its entirety for the convenience of affected operators. The effective date remains August 7, 1995.

Since this action only clarifies a current requirement, it has no adverse economic impact and imposes no additional burden on any person. Therefore, notice and public procedures hereon are unnecessary.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Correction

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39 - AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 USC 106(g), 40113, 44701.

§ 39.13 - (Amended)

2. Section 39.13 is amended by removing amendment 39-9291 (60 FR 35326, July 7, 1995), and by adding a new airworthiness directive (AD), amendment 39-9498, to read as follows: