[Federal Register Volume 71, Number 18 (Friday, January 27, 2006)]
[Rules and Regulations]
[Pages 4482-4484]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-734]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-20034; Directorate Identifier 2004-NM-178-AD; 
Amendment 39-14463; AD 2006-02-11]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-10-10, DC-
10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, 
DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain McDonnell Douglas transport category airplanes. This AD 
requires doing repetitive detailed inspections for accumulation of 
debris (blockage) in the drain holes of the pitot tubes, and cleaning 
the hole if any evidence of debris is found. This AD results from 
reports of blocked drain holes of the pitot tubes. We are issuing this 
AD to prevent blocked drain holes of the pitot tubes, which could 
result in the accumulation of water in the pitot-static system and 
consequent failure of that system. Failure of the pitot-static system 
could result in erroneous airspeed indications in the cockpit and 
consequent loss of airspeed control.

DATES: This AD becomes effective March 3, 2006.

ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street SW., Nassif Building, 
Room PL-401, Washington, DC.
    Contact Boeing Commercial Airplanes, Long Beach Division, 3855 
Lakewood Boulevard, Long Beach, California 90846, Attention: Data and 
Service Management, Dept. C1-L5A (D800-0024), for service information 
identified in this AD.

FOR FURTHER INFORMATION CONTACT: Brett Portwood, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft 
Certification Office, 3960 Paramount Boulevard, Lakewood, California 
90712-4137; telephone (562) 627-5350; fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Examining the Docket

    You may examine the airworthiness directive (AD) docket on the 
Internet at http://dms.dot.gov or in person at the Docket Management 
Facility office between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Management Facility office 
(telephone (800) 647-5227) is located on the plaza level of the Nassif 
Building at the street address stated in the ADDRESSES section.

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that would apply to certain McDonnell 
Douglas Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-
10A and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and 
MD-11F airplanes. That NPRM was published in the Federal Register on 
January 12, 2005 (70 FR 2062). That NPRM proposed to require doing 
repetitive detailed inspections for accumulation of debris (blockage) 
of the drain holes of the pitot tubes, and cleaning the hole if any 
evidence of debris is found.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Support for the NPRM

    One commenter supports the NPRM.

Requests To Extend Repetitive Interval

    Three commenters request that the 650-flight-hour interval for the 
repetitive detailed inspections in paragraph (f) of the NPRM be 
increased. One commenter, the airplane manufacturer, states that it 
originally recommended an interval of 650 flight hours because that was 
believed to be greater than the A-check interval in use at that time. 
The commenter points out that an A-check for some operators is now 
approaching 1,000 flight hours and recommends that interval. The 
commenter also states that inspection data, which cover as much as ten 
years, show that there have been no findings of blockage of the holes 
of the pitot tube drain tube since implementation of repetitive 
inspections.
    A second commenter states that it has performed the proposed 
repetitive inspections on its fleet every 2,000 flight hours since July 
1999. The results of an analysis conducted by the commenter revealed no 
events of all three pitot tube drains being blocked and only two events 
where the drain holes on one of the three pitot tubes were blocked. 
Based on this service history, the commenter does not support a 
repetitive interval of less than 2,000 flight hours.
    A third commenter states that an interval shorter than an A-check 
would require operators to perform the proposed visual and forced-air 
inspections during turnaround of the airplane. The commenter's normal 
turnaround time is 2 hours. The commenter further states that the 
proposed visual and forced air inspections take at least one hour, and 
that it takes at least an additional 20 minutes for the pitot probes to 
cool down. In addition, the commenter states that its airplanes have 
never had blockage through calcium build-up; however, it has heard from 
other operators that calcium blockage takes more than a year to build 
up. Therefore, the commenter concludes that it would be costly to do 
the proposed inspections during a turnaround and suggests an interval 
of at least 850 flight hours, preferably 1,000 flight hours.
    We agree that the repetitive inspection interval can be extended 
somewhat. Since issuance of the NPRM, we have analyzed further in-
service data from the airplane manufacturer and failure rate data for a 
blocked pitot tube from DC-10, MD-10, and MD-11 service history, which 
included 22 reported events.
    The airplane manufacturer performed an analysis using four 
maintenance intervals: 650, 700, 1,000, and 1,500 flight hours. The 
results of the analysis

[[Page 4483]]

predicted the expected number of occurrences of a single blocked pitot 
tube and the expected number of occurrences of multiple blocked pitot 
tubes, assuming the blockage occurred as a random event. Based on the 
results of this analysis, the calculated probability of multiple 
blocked pitot tubes within the four maintenance intervals was 
documented. The airplane manufacturer assumed that treating the 
blockage as a random event would address a slow blockage build-up, such 
as calcium build-up, but would not adequately address foreign object 
blockage. Furthermore, it was noted that, if the right environmental 
conditions are present, such as flying through a bug storm, a large 
blockage of more than one pitot tube could occur within a maintenance 
interval established solely based on a slow blockage build-up.
    Based on the results of the airplane manufacturer's analysis, we 
determined that we cannot rely on the random event analysis, alone, to 
determine a minimum, safe maintenance interval. As a result, we 
assessed additional safety margins to account for the non-random large 
blockage events and determined that a maintenance interval of more than 
1,000 flight hours would result in an unacceptable risk of additional 
occurrences of multiple blocked pitot tubes. Therefore, we have made a 
change to the final rule to increase the repetitive time interval to 
1,000 flight hours.

Request To Delete Forced-Air Check

    One commenter, the airplane manufacturer, requests that the forced-
air check in paragraph (h) of the NPRM be deleted. The commenter states 
that it is unsure that the forced-air check provides a benefit, and 
that there is a potential for damaging the air data equipment if the 
system were to be overpressurized during the test procedure.
    We agree. Although the forced-air check is intended to provide 
additional assurance that any microscopic debris is cleared from the 
drain holes of the pitot tubes, the airplane manufacturer is aware of 
in-service reports or incident data indicating that the forced-air 
check has caused damage to air data equipment on airplanes. Therefore, 
we have made a change to the final rule to remove the forced-air check.

Request To Revise Reference to Airplane Maintenance Manual (AMM)

    One commenter, the airplane manufacturer, requests that the 
reference to Chapter 34-11-02 of the AMM specified in paragraph (j) of 
the NPRM (re-designated as paragraph (h) in final rule) be revised to 
Chapter 34-11. The commenter states that Chapter 34-11-02 is correct 
for Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A 
and KDC-10), DC-10-40, DC-10-40F, MD-10-10F, and MD-10-30F airplanes, 
but Chapter 34-11-01 is correct for Model MD-11 and MD-11F airplanes.
    We partially agree. We do not agree to reference Chapter 34-11 
because that reference is too general. However, we will revise 
paragraph (h) of the AD to refer to the correct chapter for the 
affected airplane models as indicated by the commenter.

Request To Change Reference to Special Compliance Item (SCI)

    One commenter requests that Boeing SCI 34-2 be approved as an 
alternative method of compliance (AMOC) in the NPRM. The commenter 
believes that the current Boeing MD-11 Time Controlled Task Card, 
developed per Boeing SCI 34-2, provides an equivalent level of safety 
and complies with the intent of the NPRM.
    We do not agree. We have determined that Boeing SCI 34-2 is not 
reasonably available to all operators and the public like most Boeing 
service bulletins referenced in ADs are. Therefore, we have determined 
that incorporating by reference that service document in this AD would 
be inappropriate. However, under the provisions of paragraph (i) of 
this AD, we may consider requests for approval of such an AMOC.

Clarification of AMOC Paragraph

    We have revised this action to clarify the appropriate procedure 
for notifying the principal inspector before using any approved AMOC on 
any airplane to which the AMOC applies.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    There are about 314 airplanes of the affected design in the 
worldwide fleet. This AD will affect about 216 airplanes of U.S. 
registry. The required inspections will take about 2 work hours per 
airplane, at an average labor rate of $65 per work hour. Based on these 
figures, the estimated cost of the AD for U.S. operators is $28,080, or 
$130 per airplane, per inspection cycle.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
subtitle VII, part A, subpart III, section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will 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.
    For the reasons discussed above, I certify that this AD:
    (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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD and placed it in the AD docket. See the ADDRESSES 
section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

[[Page 4484]]

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

2006-02-11 McDonnell Douglas: Amendment 39-14463. Docket No. FAA-
2005-20034; Directorate Identifier 2004-NM-178-AD.

Effective Date

    (a) This AD becomes effective March 3, 2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all McDonnell Douglas Model DC-10-10, DC-
10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, 
DC-10-40F, MD-10-10F, MD-10-30F, MD-11, and MD-11F airplanes; 
certificated in any category.

Unsafe Condition

    (d) This AD was prompted by reports of blocked drain holes of 
the pitot tubes. We are issuing this AD to prevent blocked drain 
holes of the pitot tubes, which could result in the accumulation of 
water in the pitot-static system and consequent failure of that 
system. Failure of the pitot-static system could result in erroneous 
airspeed indications in the cockpit and consequent loss of airspeed 
control.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Repetitive Inspections

    (f) Within 90 days after the effective date of this AD, do a 
detailed inspection for accumulation of debris (blockage) in the 
drain holes of the pitot tubes in accordance with paragraph (g) of 
this AD. Repeat the inspection thereafter at intervals not to exceed 
1,000 flight hours.

    Note 1: For the purposes of this AD, a detailed inspection is 
``an intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids such as 
mirrors magnifying lenses, etc. may be necessary. Surface cleaning 
and elaborate procedures may be required.''

Visual Check

    (g) Do a visual check in accordance with paragraphs (g)(1) 
through (g)(3) of this AD. The visual check must be done by 
certificated maintenance personnel.
    (1) Make certain that the pitot heat is off and the pitot tubes 
are not hot.

    Note 2: Caution. Exercise care in checking pitot tubes to 
prevent severe burns to your hands.

    (2) Attempt to look through the left and right drain holes of 
each pitot tube.
    (3) Make sure that ambient light (or flashlight) is visible 
through both drain holes of each pitot tube.

Corrective Action

    (h) If any evidence of drain hole blockage is found during any 
inspection required by paragraph (f) or (g) of this AD, before 
further flight, clean the hole in accordance with a method approved 
by the Manager, Los Angeles Aircraft Certification Office (ACO), 
FAA. Chapter 34-11-02 of the Boeing DC-10 or MD-10 Airplane 
Maintenance Manual is one approved method for Model DC-10-10, DC-10-
10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40, 
DC-10-40F, MD-10-10F, and MD-10-30F airplanes; as applicable. 
Chapter 34-11-01 of the applicable Boeing MD-11 Airplane Maintenance 
Manual is one approved method for Model MD-11 and MD-11F airplanes.

Alternative Methods of Compliance (AMOCs)

    (i)(1) The Manager, Los Angeles ACO, FAA, has the authority to 
approve AMOCs for this AD, if requested in accordance with the 
procedures found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

Material Incorporated by Reference

    (j) None.

    Issued in Renton, Washington, on January 19, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 06-734 Filed 1-26-06; 8:45 am]
BILLING CODE 4910-13-P