[Federal Register Volume 71, Number 236 (Friday, December 8, 2006)]
[Proposed Rules]
[Pages 71099-71101]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-20863]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-26441; Directorate Identifier 2006-NM-204-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Airplanes

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

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for all Boeing Model 747 airplanes. This proposed AD would require an 
inspection of the number (No.) 2 and No. 3 windows on the left and 
right sides of the airplane to determine their part numbers, and 
related investigative and corrective actions if necessary. This 
proposed AD results from loss of a No. 3 window in-flight. We are 
proposing this AD to detect and correct cracking in the fail-safe 
interlayer of certain No. 2 and No. 3 glass windows, which could result 
in loss of the window and consequent rapid loss of cabin pressure. Loss 
of the window could also result in crew communication difficulties or 
incapacitation of the crew.

DATES: We must receive comments on this proposed AD by January 22, 
2007.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for the service information identified in this 
proposed AD.

FOR FURTHER INFORMATION CONTACT: Gary Oltman, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6443; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``FAA-2006-
26441; Directorate Identifier 2006-NM-204-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.

Examining the Docket

    You may examine the 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 DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the Docket Management System 
receives them.

Discussion

    We have received a report indicating that a number (No.) 3 window 
departed in-flight from a Boeing Model 747 airplane. Loss of the window 
resulted in rapid loss of cabin pressure, and the flightcrew made an 
emergency landing. The airplane had accumulated 36,131 total flight 
hours and 5,607 total flight cycles. Investigation revealed that a 
crack was present in the fail-safe interlayer of the No. 3 window, 
along the inner edge of the window's aluminum edge insert. When the 
structural inner glass pane cracked due to an electrical arcing event 
unassociated with the interlayer cracking, the interlayer was not able 
to support the cabin pressurization load and the window departed from 
the airplane. Subsequently, Boeing and some operators have also found 
cracks in the fail-safe interlayer of certain No. 2 and No. 3 glass 
windows, on many Model 747 airplanes. This condition, if not corrected, 
could result in loss of the window and consequent rapid loss of cabin 
pressure. Loss of the window could also result in crew communication 
difficulties or incapacitation of the crew.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 747-56A2012, dated 
August 24, 2006. The service bulletin describes procedures for doing a 
one-time inspection of the No. 2 and No. 3 windows on the left and 
right sides of the airplane to determine their part numbers (P/Ns) and 
doing related investigative and corrective actions if necessary. The 
service bulletin states that, instead of an inspection to determine the 
part number of a window, a review of maintenance records is acceptable 
if the part number of the window can be positively determined from that 
review. The service bulletin also states that if acrylic windows having 
P/N 65B07639-( ) or 65B07640-( ) are installed, no further inspections 
are necessary. The service bulletin also states that if the part number 
of the left No. 2 window, left No. 3 window, right No. 2 window, or 
right No. 3 window cannot be identified, you must assume that it is P/N 
65B27042-1, 65B27043-1, 65B27042-2, or 65B27043-2, respectively. If 
glass windows having

[[Page 71100]]

P/N 65B27042-( ), 65B27043-( ), 65B27046-( ), or 65B27047-( ) are 
installed, the service bulletin specifies doing the related 
investigative actions, which are repetitive detailed inspections for 
cracking or damage to the window. The corrective action is replacement 
of the affected window with a new window, if any of the following 
conditions are found during a detailed inspection: cracks in any fail-
safe interlayer, cracks in a glass pane, chips in a structural glass 
pane, evidence of electrical arcing, or any non-clear damage to the 
window.
    For the one-time inspection to determine the part numbers of the 
No. 2 and No. 3 windows, Table 1 of the service bulletin specifies 
doing the inspection at the earlier of the following compliance times: 
(1) Within 5,500 flight hours after the window was installed or 1,000 
flight hours after the date of the service bulletin, whichever occurs 
last, or (2) within 2 years after the date of the service bulletin. 
Table 1 states that if the number of flight hours since the window was 
installed is not known, you must assume that the window is beyond the 
5,500 flight-hour limit.
    For a window having P/N 65B27042-( ) or 65B27043-( ), Table 2 of 
the service bulletin specifies doing the related investigative action 
(detailed inspection) at the earlier of the following compliance times: 
(1) Within 5,500 flight hours after the window was installed or 1,000 
flight hours after the date of the service bulletin, whichever occurs 
last, or (2) within 2 years after the date of the service bulletin. 
Table 2 states that if the number of flight hours since the window was 
installed is not known, you must assume that the window is beyond the 
5,500 flight-hour limit. Table 2 specifies repeating the detailed 
inspection at intervals not to exceed 3,000 flight hours or 3 years, 
whichever occurs first. Table 2 also specifies replacing the window 
before further flight after the inspection, if necessary.
    For a window having P/N 65B27046-( ) or 65B27047-( ), Table 3 of 
the service bulletin specifies doing the related investigative action 
(detailed inspection) at the earlier of the following compliance times: 
(1) Within 22,000 flight hours after the window was installed or 1,000 
flight hours after the date of the service bulletin, whichever occurs 
last, or (2) within 3 years after the date of the service bulletin. 
Table 3 states that if the number of flight hours since the window was 
installed is not known, you must assume that the window is beyond the 
22,000 flight-hour limit. Table 3 specifies repeating the detailed 
inspection at intervals not to exceed 7,500 flight hours or 5 years, 
whichever occurs first. Table 3 also specifies replacing the window 
before further flight, if necessary.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other airplanes 
of this same type design. For this reason, we are proposing this AD, 
which would require accomplishing the actions specified in the service 
information described previously.

Interim Action

    This is considered to be interim action until final action is 
identified, at which time we may consider further rulemaking.

Costs of Compliance

    There are about 949 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 153 airplanes of 
U.S. registry. The proposed inspection to determine the window part 
numbers would take about 4 work hours per airplane, at an average labor 
rate of $80 per work hour. Based on these figures, the estimated cost 
of the proposed AD for U.S. operators is $48,960, or $320 per airplane.
    The proposed detailed inspection, if necessary, would take about 1 
work hour per airplane, at an average labor rate of $80 per work hour. 
Based on these figures, the estimated cost of the proposed detailed 
inspection for U.S. operators is $80 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 proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the 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. 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 proposed 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.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2006-26441; Directorate Identifier 2006-NM-
204-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by January 
22, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 
747-400F, 747SR, and 747SP series airplanes, certificated in any 
category.

[[Page 71101]]

Unsafe Condition

    (d) This AD results from loss of a number (No.) 3 window in-
flight. We are issuing this AD to detect and correct cracking in the 
fail-safe interlayer of certain No. 2 and No. 3 glass windows, which 
could result in loss of the window and consequent rapid loss of 
cabin pressure. Loss of the window could also result in crew 
communication difficulties or incapacitation of the crew.

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.

Inspection, Related Investigative Actions, and Corrective Action

    (f) Inspect the No. 2 and No. 3 windows on the left and right 
sides of the airplane to determine their part numbers (P/Ns), and do 
all the applicable related investigative and corrective actions, by 
accomplishing all of the actions specified in Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-56A2012, dated 
August 24, 2006, as applicable. Do all of these actions at the 
compliance times specified in Tables 1, 2, and 3 of paragraph 1.E. 
of the service bulletin, as applicable, except as provided by 
paragraph (g) of this AD. A review of airplane maintenance records 
is acceptable in lieu of the inspection if the part numbers of the 
windows can be conclusively determined from that review. Repeat the 
related investigative and corrective actions thereafter at the 
interval specified in Table 2 or 3 of the service bulletin, as 
applicable.

Exception to Compliance Times

    (g) Where Tables 1, 2, and 3 of paragraph 1.E. of Boeing Alert 
Service Bulletin 747-56A2012, dated August 24, 2006, specify 
counting the compliance time from ``* * * after the date on this 
service bulletin,'' this AD requires counting the compliance time 
from the effective date of this AD.

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Seattle Aircraft Certification Office (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.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by an 
Authorized Representative for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized 
by the Manager, Seattle ACO, to make those findings. For a repair 
method to be approved, the repair must meet the certification basis 
of the airplane, and the approval must specifically refer to this 
AD.

    Issued in Renton, Washington, on November 20, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-20863 Filed 12-7-06; 8:45 am]
BILLING CODE 4910-13-P