[Federal Register Volume 65, Number 83 (Friday, April 28, 2000)]
[Proposed Rules]
[Pages 24882-24887]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-10672]


========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================


Federal Register / Vol. 65, No. 83 / Friday, April 28, 2000 / 
Proposed Rules

[[Page 24882]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-326-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9-80 Series 
Airplanes and Model MD-88 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

-----------------------------------------------------------------------

SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to all McDonnell Douglas Model DC-9-80 
series airplanes and Model MD-88 airplanes, that would have superseded 
an existing AD that currently requires revisions to the Airplane Flight 
Manual (AFM) and installation of tufts and triangular decals on the 
wing upper surfaces. The proposed AD would have required installation 
of an overwing heater blanket system or a primary wing ice detection 
system and a new AFM revision. For certain airplanes, this action 
proposes new repetitive tests and a one-time inspection, as applicable, 
to ensure the integrity of the electrical installation of the overwing 
heater blanket, and corrective action, if necessary. This new action 
also proposes installation of a heater protection panel or an equipment 
protection device on certain overwing heater blanket systems, which 
would constitute terminating action for the new repetitive tests for 
affected airplanes. The actions specified by this proposed AD are 
intended to prevent ice accumulation on the wing upper surfaces, which 
could result in ingestion of ice into one or both engines and 
consequent loss of thrust from one or both engines.

DATES: Comments must be received by June 12, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-326-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 The Boeing Company, Douglas Products 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: Albert Lam, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130L, FAA, Transport Airplane 
Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount 
Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5346; 
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 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 98-NM-326-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. 98-NM-326-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to all 
McDonnell Douglas Model DC-9-80 series airplanes and Model MD-88 
airplanes, was published as a notice of proposed rulemaking (NPRM) in 
the Federal Register on March 8, 1999 (64 FR 10959). That NPRM proposed 
to supersede AD 92-03-02, amendment 39-8156 (57 FR 2014, January 17, 
1992), which is applicable to all McDonnell Douglas Model DC-9-80 
series airplanes and Model MD-88 airplanes. That proposal would have 
continued to require a revision to the Airplane Flight Manual (AFM) to 
specify restrictions on operations during icing conditions, 
installation of tufts and triangular decals on the inboard side of the 
wing upper surfaces, and a revision to the AFM to specify restrictions 
on operations when such tufts or decals are missing. That proposal 
would have added a requirement for installation of an overwing heater 
blanket system or a primary wing ice detection system, and a new 
revision to the AFM to advise the flightcrew of the hazards associated 
with ice accumulation on wing surfaces. That NPRM was prompted by 
incidents in which ice accumulation on the wing upper surfaces shed 
into the engines during takeoff. That condition, if not corrected, 
could result in consequent loss of thrust from one or both engines.

Actions Since Issuance of Previous Proposal

    Since the issuance of that NPRM, the FAA has received several 
reports of

[[Page 24883]]

arcing of overwing heater blankets installed on the wing upper 
surfaces. Investigation revealed that the arcing was caused by damaged 
wiring in an overwing heater blanket. Investigation further revealed 
that the arcing current was too low for the circuit breaker of the 
overwing heater blanket system to disconnect power to the heater 
blanket. This condition, if not corrected, could result in a fire on 
the overwing heater blanket.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas Alert Service 
Bulletin MD80-30A087, dated September 22, 1997. For airplanes on which 
an overwing heater blanket system has been installed in accordance with 
certain service bulletins or supplemental type certificates (STC), that 
service bulletin describes procedures for repetitive dielectric 
withstanding voltage and resistance tests of overwing heater blankets 
to ensure the integrity of the electrical installation of the overwing 
heater blanket and to ensure that there is no damage to the heater 
blanket. For airplanes on which the overwing heater blanket system was 
installed in accordance with TDG Aerospace, Inc., STC SA6042NM, the 
service bulletin also describes procedures for a one-time detailed 
visual inspection to detect discrepancies of the overwing heater 
blanket, including mechanical damage or punctures in the upper skin of 
the blanket, prying damage on the panel, and fuel leakage. McDonnell 
Douglas Alert Service Bulletin MD80-30A087 references TDG Aerospace 
Document E95-451, Revision B, dated January 31, 1996, as an additional 
source of service information for accomplishment of corrective actions, 
including repair or replacement of the overwing heater blanket, if any 
discrepancy is detected.
    The FAA also has reviewed and approved McDonnell Douglas Service 
Bulletin MD80-30-090, dated October 19, 1999. For airplanes on which 
the overwing heater blanket system was installed in accordance with 
certain service bulletins or STC's, that service bulletin describes 
procedures for installation of a heater protection panel (HPP) and 
associated wiring on the overwing heater blanket system, or 
modification of the existing HPP, if one is installed. Installation of 
an HPP is intended to protect the overwing heater blanket from damage 
by detecting abnormal current flow, and interrupting and shutting off 
power to the heater blanket. Accomplishment of the installation or 
modification of the HPP, as applicable, eliminates the need for the 
repetitive tests described in McDonnell Douglas Alert Service Bulletin 
MD80-30A087, dated September 22, 1997.
    Accomplishment of the actions described in these service bulletins 
is intended to adequately address the new identified unsafe condition 
(arcing of overwing heater blankets, which could result in a fire on 
the overwing heater blanket).

Comments

    Due consideration has been given to the comments received in 
response to the NPRM, and two comments have resulted in a change to 
this proposed rule.

Request To Incorporate Ground Fault Protection System

    One commenter, the airplane manufacturer, requests that the 
proposed AD be revised to add a requirement for installation of ground 
fault protection for the overwing heater blanket system. The commenter 
states no justification for its request in its comment. However, as 
stated previously, there have been several incidents of arcing of 
overwing heater blankets due to damaged wiring, and the manufacturer 
has issued McDonnell Douglas Service Bulletin MD80-30-090, described 
previously, which describes procedures for installation of ground fault 
protection.
    The FAA partially concurs with the commenter's request. The FAA 
concurs that it is necessary to require installation of ground fault 
protection for the overwing heater blanket systems installed in 
accordance with certain service bulletins or STC's. Therefore, 
paragraphs (f)(1)(i) and (f)(1)(ii) of this supplemental NPRM would 
require installation or modification, as applicable, of an HPP on any 
overwing heater blanket system installed in accordance with McDonnell 
Douglas Service Bulletin MD80-30-071, Revision 02, dated February 6, 
1996; or McDonnell Douglas Service Bulletin MD80-30-078, Revision 01, 
dated April 8, 1997. Similarly, paragraph (f)(1)(iii) of this 
supplemental NPRM proposes to require installation of an equipment 
protection device (EPD) approved by the Manager, Los Angeles Aircraft 
Certification Office, to provide ground fault protection for the 
overwing heater blanket system installed in accordance with TDG 
Aerospace, Inc., Supplemental Type Certificate (STC) SA6042NM. In 
addition, for airplanes on which overwing heater blankets are already 
installed, this supplemental NPRM proposes to require accomplishment of 
the previously described repetitive dielectric withstanding voltage and 
resistance tests of overwing heater blankets.
    However, the FAA finds that it is not necessary to require 
installation of ground fault protection for airplanes on which overwing 
heater blankets are installed in accordance with AlliedSignal STC 
SA6061NM, because a ground fault protection circuit is integrated as 
part of the system.

Request To Reference Holders of STC's

    One commenter states that, although the McDonnell Douglas service 
bulletins are quoted repeatedly in the NPRM by both name and service 
bulletin numbers, the NPRM makes no mention of the holders of the STC's 
referenced in paragraph (d)(1) of the NPRM. The commenter requests that 
the holders of the STC's be identified in the AD.
    The FAA concurs with the commenter's request. Therefore, paragraph 
(f)(1)(iii)(B) identifies TDG Aerospace, Inc., as the holder of STC 
6042NM, and paragraph (f)(1)(iii)(C) of this supplemental NPRM 
identifies AlliedSignal as the holder of STC SA6061NM.

Request To Revise Cost Impact Information

    One commenter, the airplane manufacturer, requests revisions to the 
cost impact estimates for installation of the wing heater system and 
primary wing ice detector system. Certain changes suggested by the 
commenter are related to the incorporation of the ground fault 
protection system along with the wing heater system; various other 
changes relate to the estimate of work hours and costs for installation 
of the primary wing ice detection system. The commenter provides no 
justification for its requests, but does indicate that the cost of 
parts will vary depending on factors such as parts suppliers, airplane 
fleet size, and airplane configuration.
    The FAA partially concurs with the commenter's requests. The FAA 
finds that it is appropriate to update the cost estimate in this 
supplemental NPRM to reflect the work hours and parts costs associated 
with installation of the HPP or EPD along with the wing heater system. 
Therefore, this supplemental NPRM has been revised to update the cost 
of installation of the overwing heater blankets to reflect the figures 
provided by the commenter. The FAA has also determined that it is 
appropriate to revise the estimated costs for installation of the 
primary wing ice detection system; however, the cost estimates have 
been updated to reflect

[[Page 24884]]

the most recent information provided by the manufacturer and do not 
necessarily reflect the figures provided by the commenter in its 
written comment.

Explanation of New Requirements of Proposal

    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 continue to require a revision to the Airplane Flight 
Manual (AFM) to specify restrictions on operations during icing 
conditions, installation of tufts and triangular decals on the inboard 
side of the wing upper surfaces, and a revision to the AFM to specify 
restrictions on operations when such tufts or decals are missing. The 
proposed AD would also require installation of an overwing heater 
blanket system or a primary wing ice detection system, and a new 
revision to the AFM to advise the flightcrew of the hazards associated 
with ice accumulation on wing surfaces. Installation of an overwing 
heater blanket system, if accomplished, would be required to be 
accomplished in accordance with the applicable service bulletin 
described in the NPRM, except as discussed in the ``Differences Between 
Proposed Rule and Service Bulletins'' section of the original NPRM; or 
in accordance with certain STC's. Installation of a primary wing ice 
detection system, if accomplished, would be required to be accomplished 
in accordance with a method approved by the FAA.
    For certain airplanes on which an overwing heater blanket system 
has already been installed prior to the effective date of the AD, the 
proposed AD also would require repetitive tests to ensure the integrity 
of the electrical installation of the overwing heater blanket; a one-
time inspection to detect discrepancies in repaired areas of the 
overwing heater blanket system, as applicable; and corrective action, 
if necessary. The proposed AD also would require installation or 
modification of an HPP, as applicable, or installation of an EPD, to 
provide circuit protection to the overwing heater blanket system. Such 
installation or modification, as applicable, would constitute 
terminating action for the new proposed repetitive tests for affected 
airplanes. The repetitive inspections and installation or modification 
of an HPP, as applicable, would be required to be accomplished in 
accordance with the service bulletins described previously, except as 
discussed below. Installation of an EPD would be required to be 
accomplished in accordance with a method approved by the FAA.

Explanation of Differences Between Service Bulletins and 
Supplemental NPRM

    Operators should note that, although McDonnell Douglas Service 
Bulletin MD80-30-090 recommends that an HPP be installed in conjunction 
with installation of an overwing heater blanket within 18 months after 
receipt of that service bulletin, this supplemental NPRM proposes to 
require installation of an HPP (or an EPD) within 3 years after the 
effective date of this AD. The FAA finds that it is appropriate for the 
HPP (or EPD) to be installed in conjunction with the overwing heater 
blanket system, and the compliance time for installation of the 
overwing heater blanket system specified in this proposed AD is 3 years 
after the effective date of this AD. Therefore, the FAA finds that it 
is appropriate to require installation of both the overwing heater 
blanket system and an HPP or EPD within 3 years after the effective 
date of this AD. However, for overwing heater blankets installed prior 
to the effective date of this AD without an HPP or EPD, this proposed 
AD would require repetitive tests, described previously, to ensure the 
integrity of the electrical installation of the overwing heater blanket 
(and a one-time detailed visual inspection to detect discrepancies in 
repaired areas of the overwing heater blanket system, if applicable) 
until an HPP or EPD is installed.

Conclusion

    Since these changes expand the scope of the originally proposed 
rule, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.

Cost Impact

    There are approximately 1,153 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 643 airplanes of U.S. 
registry would be affected by this proposed AD.
    The AFM revision that is currently required by AD 92-03-02 takes 
approximately 1 work hour 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 AFM revision on U.S. operators is 
estimated to be $38,580, or $60 per airplane.
    The revision of the CDL that is currently required by AD 92-03-02 
takes approximately 1 work hour per airplane to accomplish, at an 
average labor rate of $60 per work hour. Based on these figures, the 
cost impact of the CDL revision on U.S. operators is estimated to be 
$38,580, or $60 per airplane.
    The installation of tufts and decals that is currently required by 
AD 92-03-02 takes approximately 3 work hours per airplane to 
accomplish, at an average labor rate of $60 per work hour. Required 
parts cost approximately $25 per airplane. Based on these figures, the 
cost impact of the currently required installation of tufts and decals 
on U.S. operators is estimated to be $131,815, or $205 per airplane.
    The installation of the wing heater system that is proposed as one 
option for compliance with this AD action would take approximately 200 
to 350 work hours per airplane to accomplish, at an average labor rate 
of $60 per work hour. Required parts would cost approximately $76,000 
to $130,000 per airplane, depending on suppliers, airplane fleet size, 
and configuration. Based on these figures, the cost impact of the 
installation proposed by this AD on U.S. operators is estimated to 
range from $88,000 to $151,000 per airplane.
    In lieu of installation of a wing heater system, this proposed AD 
provides for installation of a primary wing ice detector system. 
Because the manufacturer has not issued service information that 
describes the procedures for such an installation, the FAA is unable at 
this time to provide specific information as to the number of work 
hours or cost of parts that would be required to accomplish that 
proposed installation. However, based on estimated costs provided by 
the manufacturer, the FAA can reasonably estimate that the proposed 
installation would require 290 work hours to accomplish, at an average 
labor rate of $60 per work hour. The cost of required parts is 
estimated to range from $30,000 to $70,000 per airplane, depending on 
fleet size and airplane configuration. Based on these figures, the cost 
impact of the installation of a primary wing ice detector system 
proposed by this AD on U.S. operators is estimated to range from 
$47,400 to $87,400 per airplane.
    The new AFM revision that is proposed in this AD action would take 
approximately 1 work hour per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the new AFM revision proposed by this AD on U.S. operators is 
estimated to be $38,580, or $60 per airplane.
    For affected airplanes, the new repetitive tests proposed in this 
AD action would take approximately 3 work hours per airplane to 
accomplish, at an

[[Page 24885]]

average labor rate of $60 per work hour. Based on these figures, the 
cost impact of the repetitive tests proposed by this AD on U.S. 
operators is estimated to be $180 per airplane, per test cycle.
    For affected airplanes, the one-time detailed visual inspection 
proposed in this AD action would take 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 detailed visual 
inspection proposed by this AD on U.S. operators is estimated to be 
$180 per airplane.
    For airplanes listed in Group 1 of McDonnell Douglas Alert Service 
Bulletin MD80-30-090, the modification of the existing HPP would take 
approximately 5 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. The manufacturer has committed 
previously to its customers that it will bear the cost of necessary 
parts. As a result, the cost of those parts is not attributable to this 
proposed AD. Based on these figures, the cost impact of the proposed AD 
on U.S. operators is estimated to be $300 per airplane.
    For airplanes listed in Group 2 of McDonnell Douglas Alert Service 
Bulletin MD80-30-090, the installation of the HPP and associated wiring 
would take approximately 3 work hours per airplane to accomplish, at an 
average labor rate of $60 per work hour. The manufacturer has committed 
previously to its customers that it will bear the cost of necessary 
parts. As a result, the cost of those parts is not attributable to this 
proposed AD. Based on these figures, the cost impact of the proposed AD 
on U.S. operators is estimated to be $180 per airplane.
    Because no service information that describes procedures for 
installation of an EPD has been issued, such installation for affected 
airplanes would be required to be accomplished in accordance with a 
method approved by the FAA, and the FAA is unable at this time to 
provide specific information as to the number of work hours that would 
be required to accomplish the proposed installation. However, based on 
the information available for installation of an HPP, the FAA estimates 
that the proposed installation of an EPD would require approximately 3 
hours per airplane, at an average labor rate of $60 per work hour. 
Based on information from the supplier on parts cost for the EPD, the 
cost of required parts is estimated to be $5,475 per airplane. Based on 
these figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $5,655 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. However, the 
FAA has been advised that the terminating modification has already been 
installed on a number of airplanes that are subject to this AD. 
Therefore, the future economic cost impact of this rule on U.S. 
operators is expected to be less than the cost impact figures indicated 
above.

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 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 39-8156 (57 FR 
2014, January 17, 1992), and by adding a new airworthiness directive 
(AD), to read as follows:

McDonnell Douglas: Docket 98-NM-326-AD. Supersedes AD 92-03-02, 
Amendment 39-8156.

    Applicability: All Model DC-9-81, -82, -83, and -87 series 
airplanes; and Model MD-88 airplanes; 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 (h)(1) 
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 prevent ice accumulation on the wing upper surfaces, which 
could result in ingestion of ice into one or both engines and 
consequent loss of thrust from one or both engines, accomplish the 
following:

Restatement of Requirements of AD 92-03-02

Airplane Flight Manual Revision

    (a) Within 10 days after January 17, 1992 (the effective date of 
AD 92-03-02, amendment 39-8156), revise the Limitations Section of 
the FAA-approved Airplane Flight Manual (AFM) to include the 
following. This may be accomplished by inserting a copy of this AD 
in the AFM.

``Ice on Wing Upper Surfaces

Caution

    Ice shedding from the wing upper surface during takeoff can 
cause severe damage to one or both engines, leading to surge, 
vibration, and complete thrust loss. The formation of ice can occur 
on wing surfaces during exposure of the airplane to normal icing 
conditions. Clear ice can also occur on the wing upper surfaces when 
cold-soaked fuel is in the main wing fuel tanks, and the airplane is 
exposed to conditions of high humidity, rain, drizzle, or fog at 
ambient temperatures well above freezing. Often, the ice 
accumulation is clear and difficult to detect visually. The ice 
forms most frequently on the inboard, aft corner of the main wing 
tanks. [END OF CAUTIONARY NOTE]
    The wing upper surfaces must be physically checked for ice when 
the airplane has been exposed to conditions conducive to ice 
formation. Takeoff may not be initiated unless the flight crew 
verifies that a visual check and a physical (hands-on) check of the 
wing upper surfaces have been accomplished, and that the wing is 
clear of ice accumulation when any of the following conditions 
occur:

[[Page 24886]]

    (1) When the ambient temperature is less than 50 degrees F and 
high humidity or visible moisture (rain, drizzle, sleet, snow, fog, 
etc.) is present;
    (2) When frost or ice is present on the lower surface of either 
wing;
    (3) After completion of de-icing.
    When tufts and triangular decals are installed in accordance 
with McDonnell Douglas MD-80 Service Bulletin 30-59, the physical 
check may be made by assuring that all installed tufts move freely.

Note

    This limitation does not relieve the requirement that aircraft 
surfaces are free of frost, snow, and ice accumulation, as required 
by Federal Aviation Regulations Sections 91.527 and 121.629. [END OF 
NOTE]''

AFM Configuration Deviation List Revision

    (b) Within 10 days after January 17, 1992, revise the 
Configuration Deviation List (CDL) Appendix of the FAA-approved AFM 
to include the following. This may be accomplished by inserting a 
copy of this AD in the AFM.

``30-80-01 Triangular Decal and Tuft Assemblies

    Up to two (2) decals or tufts per side may be missing, provided:
    (a) At least one decal and tuft on each side is located along 
the aft spar line; and
    (b) The tufts are used for performing the physical check to 
determine that the upper wing is free of ice by observing that the 
tufts move freely.
    Up to eight (8) decals and/or tufts may be missing, provided:
    (a) Takeoff may not be initiated unless the flight crew verifies 
that a physical (hands-on) check is made of the upper wing in the 
location of the missing decals and/or tufts to assure that there is 
no ice on the wing when icing conditions exist;

OR
    (b) When the ambient temperature is more than 50 degrees F.''

Installation of Tufts and Triangular Decals

    (c) Within 30 days after January 17, 1992, install tufts and 
triangular decals on the inboard side of the wings' upper surfaces, 
in accordance with McDonnell Douglas Service Bulletin 30-59, dated 
September 18, 1989; Revision 1, dated January 5, 1990; or Revision 
2, dated August 15, 1990.

New Requirements of This AD

Repetitive Tests and One-Time Inspection

    (d) For airplanes on which an overwing heater blanket system was 
installed without installation of a heater protection panel (HPP) or 
an equipment protection device (EPD) prior to the effective date of 
this AD: Within 60 days after the effective date of this AD, 
accomplish the actions specified in paragraph (d)(1) or (d)(2) of 
this AD, as applicable.
    (1) For airplanes on which the overwing heater blanket system 
was installed in accordance with McDonnell Douglas Service Bulletin 
MD80-30-071, Revision 02, dated February 6, 1996; or McDonnell 
Douglas Service Bulletin MD80-30-078, Revision 01, dated April 8, 
1997: Accomplish paragraphs (d)(1)(i) and (d)(1)(ii) of this AD.
    (i) Remove secondary access covers, and perform a one-time 
detailed visual inspection to detect discrepancies (mechanical 
damage or punctures in the upper skin of the blanket, prying damage 
on the panel, and fuel leakage) of the overwing heater blanket, in 
accordance with McDonnell Douglas Alert Service Bulletin MD80-
30A087, dated September 22, 1997. And,
    (ii) Accomplish paragraph (d)(1)(ii)(A) or (d)(1)(ii)(B) of this 
AD.
    (A) Perform dielectric withstanding voltage and resistance tests 
in accordance with McDonnell Douglas Alert Service Bulletin MD80-
30A087, dated September 22, 1997. Repeat the tests thereafter at 
intervals not to exceed 150 days, until installation of an HPP in 
accordance with paragraph (f)(1)(i) or (f)(1)(ii) of this AD, as 
applicable.
    (B) Deactivate the overwing heater blanket system until 
accomplishment of dielectric withstanding voltage and resistance 
tests specified in paragraph (1)(2)(ii)(A). If the overwing heater 
blanket system is deactivated as provided by this paragraph, 
continue to accomplish the requirements of paragraphs (a), (b), and 
(c) of this AD.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

    (2) For airplanes on which the overwing heater blanket system 
was installed in accordance with TDG Aerospace, Inc., STC SA6042NM: 
Accomplish paragraphs (d)(2)(i) and (d)(2)(ii) of this AD.
    (i) Remove secondary access covers, and perform a one-time 
detailed visual inspection to detect discrepancies (mechanical 
damage or punctures in the upper skin of the blanket, prying damage 
on the panel, and fuel leakage) of the overwing heater blanket, in 
accordance with McDonnell Douglas Alert Service Bulletin MD80-
30A087, dated September 22, 1997. And,
    (ii) Accomplish paragraph (d)(2)(ii)(A) or (d)(2)(ii)(B) of this 
AD.
    (A) Perform dielectric withstanding voltage and resistance tests 
in accordance with McDonnell Douglas Alert Service Bulletin MD80-
30A087, dated September 22, 1997. Repeat the tests thereafter at 
intervals not to exceed 150 days, until installation of an EPD in 
accordance with paragraph (f)(1)(iii)(B) of this AD.
    (B) Deactivate overwing heater blanket system until 
accomplishment of dielectric withstanding voltage and resistance 
tests specified in paragraph (d)(2)(ii)(A). If the overwing heater 
blanket system is deactivated as provided by this paragraph, 
continue to accomplish the requirements of paragraphs (a), (b), and 
(c) of this AD.

Corrective Action

    (e) If any discrepancy is detected during any inspection or test 
performed in accordance with paragraph (d) of this AD, prior to 
further flight, repair or replace the affected heater blanket, in 
accordance with McDonnell Douglas Alert Service Bulletin MD80-
30A087, dated September 22, 1997.

    Note 3: McDonnell Douglas Alert Service Bulletin MD80-30A087, 
dated September 22, 1997, references TDG Aerospace Document E95-451, 
Revision B, dated January 31, 1996, as an additional source of 
service information for accomplishment of repair or replacement of 
the overwing heater blanket.

Installation of Overwing Heater Blanket or Primary Wing Ice Detection 
System

    (f) Within 3 years after the effective date of this AD, 
accomplish the requirements of either paragraph (f)(1) or (f)(2) of 
this AD.
    (1) Accomplish the actions specified in paragraph (f)(1)(i), 
(f)(1)(ii), or (f)(1)(iii) of this AD, as applicable.
    (i) For airplanes listed in Group 1 in McDonnell Douglas Service 
Bulletin MD80-30-090, dated October 19, 1999: Install an overwing 
heater blanket system in accordance with McDonnell Douglas Service 
Bulletin MD80-30-071, Revision 02, dated February 6, 1996; and 
modify and reidentify the existing HPP in accordance with McDonnell 
Douglas Service Bulletin MD80-30-090. Modification of the existing 
HPP in accordance with this paragraph constitutes terminating action 
for the repetitive inspections required by (d)(1)(ii)(A) of this AD.
    (ii) For airplanes listed in Group 2 in McDonnell Douglas 
Service Bulletin MD80-30-090, dated October 19, 1999: Install an 
overwing heater blanket system in accordance with McDonnell Douglas 
Service Bulletin MD80-30-078, Revision 01, dated April 8, 1997; and 
install an HPP and associated wiring in accordance with McDonnell 
Douglas Service Bulletin MD80-30-090. Installation of an HPP and 
associated wiring in accordance with this paragraph constitutes 
terminating action for the repetitive inspections required by 
(d)(1)(ii)(A) of this AD.
    (iii) For airplanes other than those identified in paragraph 
(f)(1)(i) or (f)(1)(ii) of this AD: Accomplish the requirements of 
paragraph (f)(1)(iii)(A), (f)(1)(iii)(B), or (f)(1)(iii)(C) of this 
AD.
    (A) Accomplish the actions specified in either paragraph 
(f)(1)(i) or (f)(1)(ii) of this AD.
    (B) Install an overwing heater blanket system in accordance with 
TDG Aerospace, Inc., Supplemental Type Certificate (STC) SA6042NM, 
and install an EPD that provides a circuit protection function to 
the overwing heater blanket, in accordance with a method approved by 
the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, 
Transport Airplane Directorate. Installation of an EPD in accordance 
with this paragraph constitutes terminating action for the 
repetitive inspections required by (d)(2)(ii)(A) of this AD.
    (C) Install an overwing heater blanket system in accordance with 
AlliedSignal STC SA6061NM.

[[Page 24887]]

    (2) Install an FAA-approved primary wing ice detection system in 
accordance with a method approved by the Manager, Los Angeles ACO.

    Note 4: McDonnell Douglas has received FAA approval of an 
acceptable primary wing ice detection system. This modification has 
been assigned a McDonnell Douglas service bulletin number but, at 
this time, no service bulletin is available.

AFM Revision

    (g) Prior to further flight after accomplishment of the 
installation required by paragraph (f)(1) or (f)(2) of this AD, 
revise the Limitations Section of the FAA-approved AFM to include 
the following. This may be accomplished by inserting a copy of this 
AD in the AFM. After accomplishment of the installation required by 
paragraph (f) of this AD and this AFM revision, the AFM revisions 
required by paragraphs (a) and (b) of this AD may be removed from 
the AFM, and the tufts and triangular decals required by paragraph 
(c) of this AD may be removed from the airplane.

``Ice on Wing Upper Surfaces

Caution

    Ice shedding from the wing upper surface during takeoff can 
cause severe damage to one or both engines, leading to surge, 
vibration, and complete thrust loss. The formation of ice can occur 
on wing surfaces during exposure of the airplane to normal icing 
conditions. Clear ice can also occur on the wing upper surfaces when 
cold-soaked fuel is in the main wing fuel tanks, and the airplane is 
exposed to conditions of high humidity, rain, drizzle, or fog at 
ambient temperatures well above freezing. Often, the ice 
accumulation is clear and difficult to detect visually. The ice 
forms most frequently on the inboard, aft corner of the main wing 
tanks. [END OF CAUTIONARY NOTE]''

Alternative Methods of Compliance

    (h)(1) 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 ACO. 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.
    (2) Alternative methods of compliance, approved previously in 
accordance with AD 92-03-02, amendment 39-8156, are NOT approved as 
alternative methods of compliance with this AD.

    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.

Special Flight Permits

    (i) 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 April 24, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-10672 Filed 4-27-00; 8:45 am]
BILLING CODE 4910-13-P