[Federal Register Volume 65, Number 91 (Wednesday, May 10, 2000)]
[Proposed Rules]
[Pages 30025-30028]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-11722]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-255-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9-10, -20, -
30, -40 and -50 Series Airplanes and C-9 (Military) Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain McDonnell Douglas 
Model DC-9 series airplanes and C-9 (military) airplanes, that 
currently requires repetitive ultrasonic or magnetic particle 
inspections to detect cracking of the engine pylon aft upper spar 
straps (caps); and if necessary, replacement of the strap with a new 
strap, or modification of the engine pylon rear spar straps, which 
constitutes terminating action for the repetitive inspections. This 
action would require new, improved repetitive ultrasonic inspections, 
and corrective actions, if necessary. This action also would require, 
among other items, a terminating action for the repetitive inspection 
requirements. This proposal is prompted by additional reports of 
fatigue cracking in the subject area on these airplanes. The actions 
specified by the proposed AD are intended to detect and correct such 
fatigue cracking, which could result in major damage to the adjacent 
structure of the pylon aft spar upper cap, and consequent reduced 
structural integrity of the airplane.

DATES: Comments must be received by June 26, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-255-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Aircraft Group, Long Beach Division, 
3855 Lakewood Boulevard, Long Beach, California 90846, Attention: 
Technical Publications Business Administration, Dept. C1-L51 (2-60). 
This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, 
Transport Airplane Directorate, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT: Wahib Mina, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California 90712-4137; telephone (562) 627-5324; fax (562) 
627-5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained

[[Page 30026]]

in this notice may be changed in light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-NM-255-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 99-NM-255-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    In 1978, the FAA issued AD 78-01-16, amendment 39-3117, applicable 
to certain McDonnell Douglas Model DC-9 series airplanes and C-9 
(military) airplanes. That AD requires repetitive ultrasonic or 
magnetic particle inspections to detect cracking of the engine pylon 
aft upper spar straps (caps); and if necessary, replacement of the 
strap with a new strap, or modification of the engine pylon rear spar 
straps (caps), which constitutes terminating action for the repetitive 
inspections. That action was prompted by reports of fatigue cracking of 
the pylon aft upper spar straps (caps). The requirements of that AD are 
intended to detect cracks and prevent failure of the engine pylon aft 
upper spar straps (caps).

Actions Since Issuance of Previous Rule

    Since the issuance of AD 78-01-16, the FAA has received additional 
reports of fatigue cracking in the subject area on these airplanes. The 
airplanes on which the cracking occurred had accumulated between 19,000 
and 36,000 landings. Investigation revealed that the repetitive 
ultrasonic inspections, as required by AD 78-01-16, do not adequately 
detect fatigue cracking in the subject area. Such fatigue cracking, if 
not detected and corrected, could result in major damage to the 
adjacent structure of the pylon aft spar upper cap, and consequent 
reduced structural integrity of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas Alert Service 
Bulletin DC9-54A031, Revision 08, dated January 31, 2000, which 
describes procedures for new repetitive ultrasonic or magnetic particle 
inspections of the engine pylon aft upper spar straps (caps) to detect 
cracking; and corrective actions, if necessary. The corrective actions 
include reapplication of a sealant; modification of the rear spar upper 
strap (cap); and replacement of the bearing on the spar strap (cap) 
with a new annular groove bearing; as applicable. The service bulletin 
references McDonnell Douglas DC-9 Service Bulletin 54-31, Revision 4, 
dated March 28, 1991, as an additional source of service information 
for accomplishment of the modification.
    The FAA also has reviewed and approved McDonnell Douglas DC-9 
Service Bulletin 54-31, Revision 4, dated March 28, 1991. The service 
bulletin describes procedures for modification of the rear spar upper 
strap (cap), which would eliminate the need for the repetitive 
inspections specified in McDonnell Douglas Alert Service Bulletin DC9-
54A031, Revision 08, dated January 31, 2000. The modification includes 
installation of access doors on the pylon rear spars, if applicable; 
replacement of the strap on the pylon upper rear spar cap with a new 
strap using new close tolerance attaching parts; and modification of 
the pylon-to-vibration isolator link.
    Accomplishment of the actions specified in the service bulletins is 
intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would supersede AD 78-01-16 to continue to require 
repetitive ultrasonic or magnetic particle inspections to detect 
cracking of the engine pylon aft upper spar straps (caps); and if 
necessary, replacement of the strap with a new strap, or modification 
of the engine pylon rear spar straps (caps), which constitutes 
terminating action for the repetitive inspections. The proposed AD also 
would require accomplishment of the actions specified in the service 
bulletins described previously.

Cost Impact

    There are approximately 809 Model DC-9-10, -20, -30, -40 and -50 
series airplanes and C-9 (military) airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 572 airplanes of U.S. 
registry would be affected by this proposed AD.
    The ultrasonic inspection that is currently required by AD 78-01-
16, and retained in this proposed AD, takes approximately 3 work hours, 
per airplane to accomplish, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of the currently required 
actions on U.S. operators is estimated to be $180 per airplane, per 
inspection cycle.
    The new ultrasonic inspection that is proposed in this AD action 
would take approximately 4 work hours per airplane to accomplish, at an 
average labor rate of $60 per work hour. Based on these figures, the 
cost impact of the new ultrasonic inspection proposed by this AD on 
U.S. operators is estimated to be $240 per airplane, per inspection 
cycle.
    The new modification of the rear spar upper strap (cap) that is 
proposed in this AD action would take between approximately 349 and 412 
work hours depending on the configuration of the affected airplane to 
accomplish, at an average labor rate of $60 per work hour. The cost of 
required parts would be between approximately $1,865 and $7,947 per 
airplane. Based on these figures, the cost impact of the new 
modification proposed by this AD on U.S. operators is estimated to be 
between $22,805 and $32,667 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the current or proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    Should an operator elect to accomplish the optional magnetic 
particle inspection that would be provided by this AD action, it would 
take approximately 7 work hours to accomplish it, at an average labor 
rate of $60 per work hour. Based on these figures, the cost impact of 
this action would be $420 per airplane, per inspection cycle.

Regulatory Impact

    The regulations proposed herein would not have a substantial direct 
effect on the States, on the relationship between the national 
Government and the States, or on the distribution of power and 
responsibilities among the

[[Page 30027]]

various levels of government. Therefore, it is determined that this 
proposal would not have federalism implications under Executive Order 
13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-3117, and by 
adding a new airworthiness directive (AD), to read as follows:

McDonnell Douglas: Docket 99-NM-255-AD. Supersedes AD 78-01-16, 
Amendment 39-3117.

    Applicability: Model DC-9-10, -20, -30, -40, and -50 series 
airplanes, and C-9 (military) airplanes, fuselage numbers 1 through 
851, inclusive; certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (p) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To detect and correct fatigue cracking of the pylon aft upper 
spar straps (caps), which could result in major damage to the 
adjacent structure of the pylon aft spar upper cap, and consequent 
reduced structural integrity of the airplane, accomplish the 
following:

Restatement of Requirements of AD 78-01-16, Amendment 39-3117

Compliance Times

    (a) For airplanes that have accumulated 35,000 or more total 
landings as of February 13, 1978 (the effective date of AD 78-01-16, 
amendment 39-3117): Within 600 landings after February 13, 1978, 
unless already accomplished within the last 1,800 landings, and 
thereafter at intervals not to exceed 2,400 landings, accomplish the 
actions specified in paragraph (f) of this AD.
    (b) For airplanes that have accumulated between 30,000 and 
34,999 total landings inclusive, as of February 13, 1978: Within 900 
landings after February 13, 1978, unless already accomplished within 
the last 1,500 landings, and thereafter at intervals not to exceed 
2,400 landings, accomplish the actions specified in paragraph (f) of 
this AD.
    (c) For airplanes that have accumulated between 25,000 and 
29,999 total landings inclusive, as of February 13, 1978: Within 
1,200 landings after February 13, 1978, unless already accomplished 
within the last 1,200 landings, and thereafter at intervals not to 
exceed 2,400 landings, accomplish the actions specified in paragraph 
(f) of this AD.
    (d) For airplanes that have accumulated between 15,000 and 
24,999 total landings inclusive, as of February 13, 1978: Within 
2,000 landings after February 13, 1978, unless already accomplished 
within the last 400 landings, and thereafter at intervals not to 
exceed 2,400 landings, accomplish the actions specified in paragraph 
(f) of this AD.
    (e) For airplanes that have accumulated less than 15,000 total 
landings as of February 13, 1978: Within 2,000 landings after the 
accumulation of 15,000 total landings, and thereafter at intervals 
not to exceed 2,400 landings, accomplish the actions specified in 
paragraph (f) of this AD.

Repetitive Inspections and Corrective Actions

    (f) At the times specified in paragraphs (a) through (e), except 
as provided by paragraph (g) of this AD, perform an ultrasonic 
inspection of the engine pylon aft upper spar straps (caps), part 
number (P/N) 9958154-5/-6, or P/N 9958154-37/-38, to detect 
cracking, in accordance with paragraph 2.B of McDonnell Douglas DC-9 
Service Bulletin A54-31, dated December 22, 1976, or in accordance 
with a method approved by the Manager, Los Angeles Aircraft 
Certification Office (ACO), FAA, Transport Airplane Directorate.

    Note 2: Alternative methods of compliance approved previously 
prior to the effective date of this AD in accordance with the Chief, 
Aircraft Engineering Division, Western Region, are considered 
acceptable for compliance with paragraph (f) of this AD.

    (1) If there is evidence of cracking, the magnetic particle 
inspection specified in paragraph 2.C of the service bulletin may be 
used to confirm the evidence of cracking.
    (2) If any cracking is detected, prior to further flight, 
accomplish either paragraph (f)(2)(i) or (f)(2)(ii) of this AD in 
accordance with the service bulletin.
    (i) Replace the strap with a new strap, P/N 9958154-5/-6, or P/N 
9958154-37/-38, and repeat the inspection thereafter at intervals 
not to exceed 15,000 landings. Or
    (ii) Modify the engine pylon rear spar straps (caps) in 
accordance with the service bulletin. Accomplishment of the 
modification constitutes terminating action for the repetitive 
inspection requirements of this AD.

    Note 3: Modification of the engine pylon rear spar straps (caps) 
accomplished prior to the effective date of this AD in accordance 
with McDonnell Douglas DC-9 Alert Service Bulletin A54-31, Revision 
2, dated December 22, 1977; Revision 3, dated June 20, 1986; 
Revision 4, dated March 26, 1987; Revision 5, dated March 25, 1991; 
or Revision 6, dated November 23, 1992; is considered acceptable for 
compliance with the requirements of paragraph (f)(2)(ii) of this AD.

Optional Magnetic Particle Inspection

    (g) In lieu of accomplishing the ultrasonic inspection, at the 
times specified in paragraphs (a) through (e) of this AD, perform a 
magnetic particle inspection of the engine pylon aft upper spar 
straps (caps), P/N 9958154-5/-6, or P/N 9958154-37/-38, to detect 
cracking, in accordance with paragraph 2.C of McDonnell Douglas DC-9 
Service Bulletin A54-31, dated December 22, 1976. If any cracking is 
detected, prior to further flight, accomplish the action specified 
in paragraph (f) of this AD. After two bearing replacements, 
accomplish the action specified in either paragraph (f)(2)(i) or 
(f)(2)(ii) of this AD.

    Note 4: Ultrasonic or magnetic particle inspection of the engine 
pylon aft upper spar straps (caps) accomplished prior to the 
effective date of this AD in accordance with McDonnell Douglas DC-9 
Alert Service Bulletin A54-31, Revision 2, dated December 22, 1977; 
Revision 3, dated June 20, 1986; Revision 4, dated March 26, 1987; 
Revision 5, dated March 25, 1991; or Revision 6, dated November 23, 
1992; is considered acceptable for compliance with the inspection 
requirements of paragraph (f) or (g) of this AD, as applicable.

New Requirements of This AD

Repetitive Ultrasonic Inspections

    (h) For airplanes on which the modification/replacement 
specified in paragraph (f)(2)(ii) or (n) of this AD has not been 
accomplished, and on which the replacement specified in paragraph 
(f)(2)(i) of this AD has not been accomplished: Except as provided 
by paragraph (m) of this AD, perform an ultrasonic inspection of the 
engine pylon aft upper spar straps (caps) to detect cracking, in 
accordance with McDonnell Douglas Alert Service Bulletin DC9-54A031, 
Revision 08, dated January 31, 2000; at the time specified in 
paragraph

[[Page 30028]]

(h)(1), (h)(2), (h)(3), or (h)(4) of this AD, as applicable. Repeat 
this inspection thereafter at intervals not to exceed 2,400 
landings.
    Accomplishment of the ultrasonic inspection constitutes 
terminating action for the repetitive inspection requirements of 
paragraphs (a) through (f), (f)(2)(i), and (g) of this AD.
    (1) For airplanes that have accumulated between 15,000 and 
24,999 total landings as of the effective date of this AD: Within 
2,000 landings or 6 months after the effective date of this AD, 
whichever occurs later.
    (2) For airplanes that have accumulated between 25,000 and 
29,999 total landings as of the effective date of this AD: Within 
1,200 landings or 6 months after the effective date of this AD, 
whichever occurs later.
    (3) For airplanes that have accumulated between 30,000 and 
34,999 total landings as of the effective date of this AD: Within 
900 landings or 6 months after the effective date of this AD, 
whichever occurs later.
    (4) For airplanes that have accumulated 35,000 or more total 
landings as of the effective date of this AD: Within 600 landings or 
6 months after the effective date of this AD, whichever occurs 
later.
    (i) For airplanes on which the modification/replacement 
specified in paragraph (f)(2)(ii) or (n) of this AD has not been 
accomplished, and on which the replacement specified in paragraph 
(f)(2)(i) of this AD has been accomplished: Except as provided by 
paragraph (m) of this AD, perform an ultrasonic inspection of the 
engine pylon aft upper spar straps (caps) to detect cracking, in 
accordance with McDonnell Douglas Alert Service Bulletin DC9-54A031, 
Revision 08, dated January 31, 2000; at the time specified in 
paragraph (i)(1), (i)(2), (i)(3), or (i)(4) of this AD, as 
applicable. Repeat this inspection thereafter at intervals not to 
exceed 2,400 landings.
    (1) For airplanes that have accumulated between 15,000 and 
24,999 landings since installation of the new spar strap (cap): 
Within 2,000 landings or 6 months after the effective date of this 
AD, whichever occurs later.
    (2) For airplanes that have accumulated between 25,000 and 
29,999 landings since installation of the new spar strap (cap): 
Within 1,200 landings or 6 months after the effective date of this 
AD, whichever occurs later.
    (3) For airplanes that have accumulated between 30,000 and 
34,999 landings since installation of the new spar strap (cap): 
Within 900 landings or 6 months after the effective date of this AD, 
whichever occurs later.
    (4) For airplanes that have accumulated 35,000 or more landings 
since installation of the new spar strap (cap): Within 600 landings 
or 6 months after the effective date of this AD, whichever occurs 
later.
    (j) If no cracking is detected during any inspection required by 
paragraph (h), (i), or (m) of this AD, prior to further flight, 
reapply sealant in accordance with McDonnell Douglas Alert Service 
Bulletin DC9-54A031, Revision 08, dated January 31, 2000.
    (k) If any cracking is detected during any inspection required 
by paragraph (h) or (i) of this AD, prior to further flight, 
accomplish the actions specified in paragraph (m) of this AD.
    (l) If any cracking is detected during any inspection required 
by paragraph (h), (i), or (m) of this AD, prior to further flight, 
modify the rear spar upper strap (cap) in accordance with McDonnell 
Douglas DC-9 Service Bulletin 54-31, Revision 4, dated March 28, 
1991. Accomplishment of the modification constitutes terminating 
action for the repetitive inspection requirements of paragraphs (h) 
and (i) of this AD.
    (m) In lieu of accomplishing the ultrasonic inspection required 
by paragraphs (h) and (i) of this AD, at the applicable times 
specified in paragraphs (h), (h)(1), (h)(2), (h)(3), (h)(4), (i), 
(i)(1), (i)(2), (i)(3), or (i)(4) of this AD, perform a magnetic 
particle inspection of the engine pylon aft upper spar strap (cap) 
for cracks, in accordance with McDonnell Douglas Alert Service 
Bulletin DC9-54A031, Revision 08, dated January 31, 2000. If no 
cracking is detected, prior to further flight, replace the bearing 
on the spar strap (cap) with a new annular groove bearing, in 
accordance with the service bulletin.

Terminating Modification

    (n) Prior to the accumulation of 100,000 total landings, or 
within 6 months after the effective date of this AD, whichever 
occurs later, modify the rear spar upper strap (cap) in accordance 
with McDonnell Douglas DC-9 Service Bulletin 54-31, Revision 4, 
dated March 28, 1991. Accomplishment of the modification constitutes 
terminating action for the repetitive inspection requirements of 
paragraphs (h) and (i) of this AD.
    (o) Accomplishment of the modification required by paragraph (l) 
or (n) of this AD constitutes compliance with the following:
    (1) The actions specified in McDonnell Douglas Service Bulletin 
54-27, Revision 4, dated April 2, 1990, that are required by AD 96-
10-11, amendment 39-9618 (61 FR 24675, May 16, 1996) [which 
references ``DC-9/MD80 Aging Aircraft Service Action Requirements 
Document'' (SARD), McDonnell Douglas Report MDC K1572, Revision B, 
dated January 15, 1993, as the appropriate source of service 
information for accomplishment of the modification]; and
    (2) The requirements of AD 72-09-01, amendment 39-2844 (which 
references McDonnell Douglas Service Bulletin 54-31, dated August 
24, 1976, and McDonnell Douglas Service Bulletin 54-27, Revision 4, 
dated April 2, 1990, as appropriate sources of service information 
for accomplishment of the modification).

Alternative Methods of Compliance

    (p) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Los Angeles Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Los Angeles ACO.

    Note 5: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.


    Note 6: Alternative methods of compliance, approved previously 
in accordance with AD 78-01-16, amendment 39-3117, are approved as 
alternative methods of compliance with this AD.

Special Flight Permits

    (q) 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.

    Issued in Renton, Washington, on May 3, 2000.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-11722 Filed 5-9-00; 8:45 am]
BILLING CODE 4910-13-U