Airworthiness Directives; McDonnell Douglas Model MD-11 Series Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-216-AD; Amendment 39-8973; AD 94-15-02]

Airworthiness Directives; McDonnell Douglas Model MD-11 Series

Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive

(AD), applicable to certain McDonnell Douglas Model MD-11 series

airplanes, that currently requires inspections to verify the

installation of shear pins, shear pin retainers, and shear pin retainer

attaching parts in the aft end of the center pylon thrust link, and

repair, if necessary. That AD was prompted by a report that both shear

pins that attach the aft end of the center engine pylon thrust link to

the tail pylon were missing. This amendment adds inspections to verify

that the shear pin retainer attaching parts are tightened within

specified limits; and adds a terminating modification for those

inspections. This amendment also expands the applicability of the rule

to include additional airplanes. The actions specified by this AD are

intended to prevent structural damage to the engine mount structure,

which could lead to loss of airplane components.

DATES: Effective August 19, 1994.

The incorporation by reference of McDonnell Douglas Alert Service

Bulletin A54-31, Revision 1, dated June 3, 1993, as listed in the

regulations, is approved by the Director of the Federal Register as of

August 19, 1994.

The incorporation by reference of McDonnell Douglas Alert Service

Bulletin A54-31, dated September 17, 1992, as listed in the

regulations, was previously approved by the Director of the Federal

Register of November 2, 1992 (57 FR 47991, October 21, 1992).

ADDRESSES: The service information referenced in this AD may be

obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach,

CA 90801-1771, Attention: Business Unit Manager, Technical

Administrative Support, Dept. L51, M.C. 2-98. This information may be

examined at the Federal Aviation Administration (FAA), Transport

Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton,

Washington; or at the FAA, Transport Airplane Directorate, Los Angeles

Aircraft Certification Office, 3229 East Spring Street, Long Beach,

California; or at the Office of the Federal Register, 800 North Capitol

Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Wahib Mina, Aerospace Engineer,

Airframe Branch, ANM-121L, FAA, Transport Airplane Directorate, Los

Angeles Aircraft Certification Office, 3229 East Spring Street, Long

Beach, California 90806-2425; telephone (310) 988-5324; fax (310) 988-

5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) by superseding AD 92-23-03,

amendment 39-8403 (57 FR 47991, October 21, 1992), which is applicable

to certain McDonnell Douglas Model MD-11 series airplanes, was

published in the Federal Register on March 17, 1994 (59 FR 12558). The

action proposed to continue to require repetitive visual inspections to

verify the installation of the shear pins, the shear pin retainers, and

the shear pin retainer attaching parts in the aft end of the center

engine (No. 2) pylon thrust link. It also proposed (1) to add

repetitive inspections to verify that the shear pin retainer attaching

parts are tightened within specified limits; (2) to delete the

previously provided ``optional terminating action'' (which consists of

a one-time verification for tightness of the nuts of the four shear pin

retainer attaching bolts); and (3) to require eventual replacement of

the existing retainer and attaching parts with a new retainer and

attaching parts, as terminating action for the currently required

repetitive visual inspections and the proposed repetitive verifications

of tightness.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. Due consideration has been given to

the comments received.

One commenter supports the proposal.

The Air Transport Association (ATA) of America, on behalf of one

member operator, and the manufacturer request that the proposed AD be

revised to indicate that the 60-day repetitive inspection specified in

paragraph (a) and (b) be required only until either the initial

verification for tightness (of the shear pin retainer attaching parts),

the terminating action, or an FAA-approved repair is accomplished.

These commenters state that the FAA already has approved repairs

applicable to paragraphs (a) and (b) of the proposal, which have

consisted of the installation of new parts. New parts obviously will be

tightened upon installation; therefore, reinspection of the tightness

of these parts within 60 days appears to be unwarranted. The commenters

request that the repetitive interval for the inspection for

installation of parts be revised to 18 months in order to be consistent

with the recommendations of Phase 2 of the original issue of McDonnell

Douglas Alert Service Bulletin A54-71.

The FAA concurs in part with the commenter's request. Upon further

consideration of the procedures specified in the referenced service

bulletin, the FAA concurs that a 60-day repetitive inspection interval

is not necessary in certain situations, explained as follows:

Paragraphs (a)(1) and (b)(1)(i) of the final rule apply to

situations where the shear pins, shear pin retainers, and shear pin

retainer attaching parts have been inspected and found to be installed.

The FAA finds that inspections to verify the installation of these

parts must be repeated every 60 days, so long as there is no other

action accomplished that will ensure the tightness of the attaching

parts. These inspections for installation may be terminated, however,

when the initial verification for tightness of the shear pin retainer

attaching parts is accomplished in 18 months in accordance with

paragraph (c) of the rule; or when the terminating modification

described in paragraph (d) is installed, if earlier than 18 months.

The FAA has revised paragraphs (a)(2) and (b)(1)(ii) of the final

rule, which apply to situations where any shear pin is missing or has

migrated, and any shear pin retainer or shear pin retainer attaching

part is missing. In such cases, an FAA-approved repair is required to

be installed; the FAA has determined that these approved repairs will

be such that no further inspections for installation of parts will be

necessary once the approved repair is installed. The FAA has revised

these paragraphs of the final rule to reflect this determination.

Additionally, the FAA has added new paragraphs (a)(3) and

(b)(1)(iii), which specify that, in situations where the shear pin

retainers or shear pin retainer attaching parts are missing or loose,

and the shear pin has not migrated, operators may accomplish a repair

in accordance with procedures specified as ``Condition II'' in

McDonnell Douglas Alert Service Bulletin A54-31, Revision 1, dated June

3, 1993. Subsequent to this repair, no further inspections for

installation of parts are required. These paragraphs have been added in

order to provide operators with an additional repair procedure that may

be used in lieu of obtaining prior FAA-approval of repairs (which was

the only option provided for in the proposal).

These same commenters contend that the 15-day compliance time for

the initial inspection required by proposed paragraph (b) is not

warranted for certain airplanes. The commenters point out that a

tightness check was accomplished on airplanes in Groups V and VI (as

specified in the referenced McDonnell Douglas service bulletin) prior

to delivery; therefore, an initial inspection for installation of the

subject parts should not be required for these airplanes. The

commenters request that, for these airplanes, only a ``re-

verification'' for tightness be required within 18 months.

Additionally, the commenters point out that an initial visual

inspection for installation of parts was accomplished on airplanes in

Group III and IV prior to delivery; therefore, the compliance time for

initial inspection for installation of parts required by this proposed

rule should be extended. The commenters suggest extending the initial

compliance time to 60 days, since this is the compliance time

recommended by the manufacturer in the referenced service bulletin.

The FAA concurs in part with the commenter's requests. The FAA

acknowledges that it is appropriate to revise paragraph (b) of the

final rule to differentiate between the requirements of the various

groups of airplanes specified in the referenced service bulletin:

As for airplanes in Groups III and IV, the FAA does not concur with

the commenter's request to extend the initial compliance time for the

inspection for installation of parts on these airplanes. While these

airplanes may have been inspected prior to delivery, and while the

manufacturer's revised service bulletin recommends a repetitive

inspection interval of 60 days, the FAA points out that the inspection

procedures described in that service bulletin have not been mandated

previously. Since the revised service bulletin was released over a year

ago, there is no way to guarantee that affected airplanes have been

repetitively inspected prior to the issuance of this final rule. In

light of this, the FAA considers a compliance time of 15 days necessary

in order to ensure that the accomplishment of what may be the first

repetitive inspection for some airplanes is carried out in a timely

manner. However, the FAA has revised the compliance terms of paragraph

(b)(1) to provide a ``grace period'' for operators of airplanes that

may have been visually (re-)inspected recently. The final rule now

reflects a compliance time for the initial visual inspection as

``within 15 days after the effective date of the AD, or prior to the

accumulation of 60 days since the last visual inspection, whichever

occurs later.''

As for airplanes in Groups V and VI, the FAA concurs that these

airplanes need not be subject to the initial inspection for

installation of parts as required by paragraph (b), as long as

repetitive verifications for tightness are conducted. Therefore, the

FAA has revised paragraph (b) by adding a new paragraph (b)(2), which

addresses these airplanes and allows them the option of either

repetitively inspecting for installation of parts (as originally

proposed), or conducting a verification for tightness within 18 months

after the last verification was performed. If operators of these

airplanes elect to perform the verification for tightness, it must be

repeated every 18 months until the terminating modification is

accomplished in accordance with paragraph (d) of the rule.

These same commenters request that proposed paragraph (c) be

revised to indicate that accomplishment of the verification for

tightness of the shear pin retainer attaching parts terminates the

requirement for the repetitive visual inspections for installation of

these same parts required by paragraph (a) and (b). The FAA concurs and

has revised paragraph (c) of the final rule accordingly.

These commenters also request that proposed paragraph (d) be

revised to extend the compliance time for accomplishment of the

terminating modification from the proposed 3 years to 5 years. The

commenters consider this modification to be only an ``improvement

change,'' and operators should be allowed to install it during a

convenient and regularly scheduled maintenance period in order to avoid

special scheduling of airplanes and additional associated costs. The

FAA does not concur. In developing the compliance time for the

terminating action, the FAA considered not only the safety

implications, but the manufacturer's recommendations, the availability

of required modification parts, and the practical aspects of an orderly

modification of the fleet. In consideration of all of these items, the

FAA determined that 3 years is an appropriate interval that will

coincide with regularly scheduled maintenance periods (``C'' checks)

for the majority of the affected operators. However, under the

provisions of paragraph (f) of the final rule, the FAA may approve

requests for adjustments to the compliance time if data are submitted

to substantiate that such an adjustment would provide an acceptable

level of safety.

After careful review of the available data, including the comments

noted above, the FAA has determined that air safety and the public

interest require the adoption of the rule with the changes previously

described. The FAA has determined that these changes will neither

increase the economic burden on any operator nor increase the scope of

the AD.

There are approximately 94 Model MD-11 series airplanes of the

affected design in the worldwide fleet. The FAA estimates that 42

airplanes of U.S. registry will be affected by this AD.

Accomplishment of the required inspections for installation of

parts will take approximately 4 work hours per airplane, at an average

labor rate of $55 per work hour. Based on these figures, the total cost

impact of these requirements of this AD on U.S. operators is estimated

to be $9,240, or $220 per airplane, per inspection.

Accomplishment of the required verification for tightness of the

shear pin retainer attaching parts will take approximately 6 work hours

per airplane, at an average labor rate of $55 per work hour. Based on

these figures, the total cost impact of these requirements of this AD

on U.S. operators is estimated to be $13,860, or $330 per airplane, per

verification.

Accomplishment of the required terminating modification will take

approximately 6 work hours per airplane, at an average labor rate of

$55 per work hour. Required parts will be provided by the manufacturer

at no cost to operators. Based on these figures, the total cost impact

of these requirements of this AD on U.S. operators is estimated to be

$13,860, or $330 per airplane.

The total cost impact figures discussed above are based on

assumptions that no operator has yet accomplished any of the

requirements of this AD action, and that no operator would accomplish

those actions in the future if this AD were not adopted.

The regulations adopted herein will not have substantial direct

effects on the States, on the relationship between the national

government and the States, or on the distribution of power and

responsibilities among the various levels of government. Therefore, in

accordance with Executive Order 12612, it is determined that this final

rule does not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is

not a ``significant regulatory action'' under Executive Order 12866;

(2) is not a ``significant rule'' under DOT Regulatory Policies and

Procedures (44 FR 11034, February 26, 1979); and (3) will not have a

significant economic impact, positive or negative, on a substantial

number of small entities under the criteria of the Regulatory

Flexibility Act. A final evaluation has been prepared for this action

and it is contained in the Rules Docket. A copy of it may be obtained

from the Rules Docket at the location provided under the caption

ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by

reference, Safety. Adoption of the Amendment

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 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.

106(g); and 14 CFR 11.89.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing amendment 39-8403 (57 FR

47991, October 21, 1992), and by adding a new airworthiness directive

(AD), amendment 39-8973, to read as follows:

94-15-02 McDonnell Douglas: Amendment 39-8973. Docket 93-NM-216-AD.

Supersedes AD 92-23-03, Amendment 39-8403.

Applicability: Model MD-11 series airplanes; as listed in

McDonnell Douglas MD-11 Alert Service Bulletin A54-31, dated

September 17, 1992, and McDonnell Douglas MD-11 Alert Service

Bulletin A54-31, Revision 1, dated June 3, 1993; certificated in any

category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent structural damage to the engine mount structure,

which could lead to loss of airplane components, accomplish the

following:

(a) For airplanes listed in McDonnell Douglas MD-11 Alert

Service Bulletin A54-31, dated September 17, 1992: Within 15 days

after November 5, 1992 (the effective date of AD 92-23-03, amendment

39-8403), unless previously accomplished within the last 30 days,

perform a visual inspection of the thrust link of the center engine

forward mount to verify installation of the shear pins, the shear

pin retainers, and the shear pin retainer attaching parts in

accordance with McDonnell Douglas MD-11 Alert Service Bulletin A54-

31, dated September 17, 1992, or Revision 1, dated June 3, 1993.

(1) If shear pins, shear pin retainers, and shear pin retainer

attaching parts are installed, repeat the visual inspection

thereafter at intervals not to exceed 60 days until accomplishment

of paragraph (c) or (d) of this AD.

(2) If any shear pin retainer or shear pin retainer attaching

part is missing or loose, and if any shear pin has migrated, prior

to further flight, repair in accordance with a method approved by

the Manager, Los Angeles Aircraft Certification Office (ACO), FAA,

Transport Airplane Directorate.

(3) If any shear pin retainer or shear pin retainer attaching

part is missing or loose, and if no shear pin has migrated, prior to

further flight, repair in acordance with ``Condition II'' of

McDonnell Douglas MD-11 Alert Service Bulletin A54-31, Revision 1,

dated June 3, 1994.

(b) For airplanes listed in McDonnell Douglas MD-11 Alert

Service Bulletin A54-31, Revision 1, dated June 3, 1993, and not

subject to the requirements of paragraph (a) of this AD, accomplish

the following:

(1) For airplanes specified as Groups III and IV in that service

bulletin: Within 15 days after the effective date of this AD or

prior to the accumulation of 60 days since the last visual

inspection performed before the effective date of this AD in

accordance McDonnell Douglas MD-11 Alert Service Bulletin A54-31,

Revision 1, dated June 3, 1993, or equivalent, whichever occurs

later, perform a visual inspection of the thrust link of the center

engine forward mount to verify installation of the shear pins, the

shear pin retainers, and the shear pin retainer attaching parts in

accordance with McDonnell Douglas MD-11 Alert Service Bulletin A54-

31, Revision 1, dated June 3, 1993.

(i) If shear pins, shear pin retainers, and shear pin retainer

attaching parts are installed, repeat the visual inspection

thereafter at intervals not to exceed 60 days until accomplishment

of paragraph (c) or (d) of this AD.

(ii) If any shear pin retainer or shear pin retainer attaching

part is loose or missing, and if any shear pin has migrated, prior

to further flight, repair in accordance with a method approved by

the Manager, Los Angeles Aircraft Certification Office (ACO), FAA,

Transport Airplane Directorate.

(iii) If any shear pin retainer or shear pin retainer attaching

part is loose or missing, and if no shear pin has migrated, prior to

further flight, repair in accordance with ``Condition II'' of

McDonnell Douglas MD-11 Alert Service Bulletin A54-31, Revision 1,

dated June 3, 1993.

(2) For airplanes specified as Groups V and VI in that service

bulletin: Accomplish the procedures specified in either paragraph

(b)(2)(i) or (b)(2)(ii) of this AD:

(i) Accomplish the visual inspection(s) and necessary follow-on

procedures specified in paragraph (b)(1) of this AD, or

(ii) Prior to the accumulation of 18 months since the last

verification for tightness of the shear pin retainer parts was

accomplished, or within 6 months after the effective date of this

AD, whichever occurs later, verify that the tightness of the shear

pin retainer parts is within the limits specified in accordance with

McDonnell Douglas MD-11 Alert Service Bulletin A54-31, Revision 1,

dated June 3, 1993. Repeat the verification for tightness thereafter

at intervals not to exceed 18 months until the accomplishment of

paragraph (d) of this AD.

(c) For all airplanes, except those subject to paragraph

(b)(2)(ii) of this AD: Within 18 months after the effective date of

this AD, verify that the tightness of the shear pin retainer

attaching parts is within the limits specified in accordance with

McDonnell Douglas MD-11 Alert Service Bulletin A54-31, Revision 1,

dated June 3, 1993. Repeat this verification thereafter at intervals

not to exceed 18 months until accomplishment of paragraph (d) of

this AD. Accomplishment of the verification for tightness required

by this paragraph constitutes terminating action for the repetitive

inspections for installation of parts required by paragraphs (a) and

(b) of this AD.

(d) For all airplanes: Within 3 years after the effective date

of this AD, replace the existing retainer and bolts with safety wire

with a new retainer and new bolts with safety wire in accordance

with McDonnell Douglas MD-11 Alert Service Bulletin A54-31, Revision

1, dated June 3, 1993. Accomplishment of this replacement

constitutes terminating action for the repetitive actions required

by paragraphs (a), (b) and (c) of this AD.

(e) Within 15 days after detecting any discrepancy during any

inspection or verification action required by this AD, submit a

report of the inspection results to the Manager, Los Angeles ACO,

FAA, Transport Airplane Directorate, 3229 East Spring Street, Long

Beach, California 90806-2425; fax (310) 988-5210. Information

collection requirements contained in this regulation have been

approved by the Office of Management and Budget (OMB) under the

provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et

seq.) and have been assigned OMB Control Number 2120-0056.

(f) Special flight permits may be issued in accordance with

sections 21.197 and 21.199 of the Federal Aviation Regulations (14

CFR 21.197 and 21.199) to operate the airplane to a location where

the requirements of this AD can be accomplished.

(g) The actions shall be done in accordance with McDonnell

Douglas MD-11 Alert Service Bulletin A54-31, dated September 17,

1992; and McDonnell Douglas MD-11 Alert Service Bulletin A54-31,

Revision 1, dated June 3, 1993. The incorporation by reference of

the former service bulletin was approved previously by the Director

of the Federal Register, in accordance with 5 U.S.C. 552(a) and 1

CFR part 51, as of November 2, 1992 (57 FR 47991, October 21, 1992).

The incorporation by reference of the latter service bulletin was

approved by the Director of the Federal Register in accordance with

5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from

McDonnell Douglas Corporation, P.O. Box 1771, Long Beach, CA 90801-

1771, Attention: Business Unit Manager, Technical Administrative

Support, Dept. L51, M.C. 2-98. Copies may be inspected at the FAA,

Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,

Washington; or at the FAA, Transport Airplane Directorate, Los

Angeles Aircraft Certification Office, 3229 East Spring Street, Long

Beach, California; or at the Office of the Federal Register, 800

North Capitol Street, NW., suite 700, Washington, DC.

(h) This amendment becomes effective on August 19, 1994.

Issued in Renton, Washington, on July 11, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-17196 Filed 7-19-94; 8:45 am]

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