[Federal Register Volume 59, Number 29 (Friday, February 11, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-2182]
[[Page Unknown]]
[Federal Register: February 11, 1994]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 93-NM-128-AD; Amendment 39-8812; AD 94-03-05]
Airworthiness Directives; Boeing Model 747-200B, -200C, -300, -
400, and -400D Series Airplanes Equipped With Passenger Oxygen System
Reservoir Mask Assemblies, Boeing Part Numbers 10-60137-152 through -
165
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Boeing Model 747-200B, -200C, -300, -400, and
400D series airplanes, that requires a revision to the FAA-approved
maintenance program to require unrestricted opening of the passenger
service unit (PSU) door during functional testing of the passenger
oxygen system; and requires an inspection to detect leaks in certain
passenger oxygen system reservoir bags, and marking and replacement of
damaged mask assemblies. This amendment is prompted by reports that the
passenger oxygen mask reservoir bags became overpressurized and split
at the seams, resulting in failure of the bags. The actions specified
by this AD are intended to ensure the delivery of emergency oxygen
through the passenger oxygen system reservoir mask assemblies.
DATES: Effective March 14, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of March 14, 1994.
ADDRESSES: The service information referenced in this AD may be
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle,
Washington 98124-2207. This information may be examined at the Federal
Aviation Administration (FAA), Transport Airplane Directorate, Rules
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
FOR FURTHER INFORMATION CONTACT: Kathi Ishimaru, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue,
SW., Renton, Washington 98055-4056; telephone (206) 227-2674; fax (206)
227-1181.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations to include an airworthiness directive (AD) that is
applicable to certain Boeing Model 747-200B, -200C, -300, -400, and -
400D series airplanes was published in the Federal Register on August
23, 1993 (58 FR 44468). That action proposed to revise the FAA-approved
maintenance program to require unrestricted opening of the passenger
service unit (PSU) door during functional testing of the passenger
oxygen system; and to require an inspection to detect leaks in certain
passenger oxygen system reservoir bags, and marking and replacement of
damaged mask assemblies.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received. -
Two commenters support the proposed rule.
One commenter notes that an unsafe condition does not exist since
its airplanes are equipped with approximately 20 percent more oxygen
masks than the maximum number of passengers, and the projected failure
rate for these masks is estimated to be only 10 to 15 percent. From
this comment, the FAA infers that the commenter is requesting that the
rule be withdrawn. The FAA does not concur. Although the projected
failure rate is lower than the number of available masks, the FAA has
determined that passengers using defective masks may not realize that
the masks are supplying an insufficient quantity of oxygen; and thus,
passengers would not seek out spare oxygen masks. Therefore, the
potential would still exist for passengers to be unable to obtain
unrestricted delivery of emergency oxygen through the passenger oxygen
system reservoir mask assembly. This AD action addresses that potential
unsafe condition.
Boeing Commercial Airplane Group requests that the applicability of
the proposal be revised to exclude airplanes that were delivered prior
to August 1991. Boeing indicates that data have demonstrated that the
masks installed on those airplanes have had significantly fewer leaks/
failures than masks installed on airplanes that were delivered after
August 1991; therefore, those earlier airplanes would not necessarily
be subject to the same unsafe condition addressed by the proposed AD
action. The FAA does not concur with the commenter's request to exclude
certain airplanes from the applicability. The FAA has reviewed the new
data concerning the failure rate of the subject masks, which indicate
that the masks' failure rate is lower than previously anticipated.
While the data do demonstrate that airplanes delivered prior to August
1991 have had significantly fewer leaking masks that fail to provide
oxygen at or above FAA-required levels than those airplanes delivered
in August 1991 and later, the FAA does not consider that this lower
failure rate warrants the exclusion of any airplanes from the
requirements of the rule. However, in light of the lower than
originally anticipated failure rates for all of these masks, coupled
with the unlikely event of decompression of the airplane, the FAA has
reconsidered the proposed compliance time for inspection and
replacement of the masks, and has determined that the compliance time
can be extended for all airplanes without adversely affecting safety.
Accordingly, the final rule has been revised to require a 15-month
compliance time for Model 747-200B, -200C, and -300 series airplanes
(the earlier-delivered airplanes), and a 180-day compliance time for
Model 747-400 and -400D series airplanes.
Several other commenters request that the proposed compliance time
of 45 days to inspect and replace the masks be extended for a variety
of reasons: Two of these commenters request that the proposed
compliance time be revised to coincide with operators' regularly
scheduled maintenance periods. One of these commenters suggests an
alternative compliance time of ``the next 3C check'' for Model 747-200
series airplanes, and ``the next 2C check'' for Model 747-400 series
airplanes. One of these commenters did not offer an alternative
suggestion to the proposed compliance time; however, the commenter
asserts that the supplier of these replacement oxygen masks cannot
deliver an adequate quantity of original or modified oxygen masks
within the proposed compliance time, therefore an extension is
necessary. Another commenter requests that the proposed compliance time
be revised to coincide with the time at which a newly-designed mask is
anticipated to become available. As discussed above, the FAA has
extended the compliance time for the required actions, although not for
the reasons requested by these commenters. The extended compliance
time, however, should be sufficient to allow the inspection and
replacement actions to be accomplished during normally scheduled
maintenance, and to allow for any anticipated new mask design to become
available.
Several commenters request that the proposal be revised to include
an option to replace the currently installed passenger oxygen masks
with improved oxygen masks. These commenters request that installation
of these improved oxygen masks eliminate the need to perform a one-time
visual inspection to detect leaks in the passenger oxygen system
reservoir bags. The FAA does not concur. The FAA acknowledges that
Boeing is currently developing new passenger oxygen masks; however,
those masks are not yet available. The FAA considers that delaying this
action until the masks are available would be inappropriate. Since an
unsafe condition exists, the FAA finds that defective masks must be
replaced to ensure continued safety. Therefore, when the improved masks
are developed, approved, and available, affected operators may request
approval to install these improved masks as an alternative method of
compliance, under the provisions of paragraph (e) of the final rule. -
Two commenters note that the cost estimate presented in the
preamble to the Notice was too low and did not take into account the
time to clean, sanitize, repack, and stow the passenger oxygen masks
following the proposed inspection. The commenters state that the
required inspection, and the consequent cleaning, sanitizing,
repacking, and stowing of the oxygen masks would necessitate
approximately 90 work hours. After considering the data presented by
commenters, the FAA concurs that the number of work hours required to
accomplish the required actions is higher than previously approximated;
the economic impact information, below, has been revised to indicate
this higher amount. The economic analysis, however, is limited only to
the cost of actions actually required by the rule. It does not consider
the costs of ``on condition'' actions, e.g., ``repair, if necessary,''
since those actions would be required to be accomplished, regardless of
AD direction, in order to correct an unsafe condition identified in an
airplane and to ensure operation of that airplane in an airworthy
condition, as required by the Federal Aviation Regulations.
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the changes previously
described. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
There are approximately 160 Boeing Model 747-200B, -200C, -300, -
400, and -400D series airplanes of the affected design in the worldwide
fleet. The FAA estimates that 25 airplanes of U.S. registry will be
affected by this AD, that it will take approximately 90 work hours per
airplane to accomplish the required actions, and that the average labor
rate is $55 per work hour. Based on these figures, the total cost
impact of the AD on U.S. operators is estimated to be $123,750, or
$4,950 per airplane. This total cost figure assumes that no operator
has yet accomplished the requirements of this AD.
The regulations adopted herein will not have substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government. Therefore, in
accordance with Executive Order 12612, it is determined that this final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a
significant economic impact, positive or negative, on a substantial
number of small entities under the criteria of the Regulatory
Flexibility Act. A final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from the Rules Docket at the location provided under the caption
``ADDRESSES.''
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends 14 CFR part
39 of the Federal Aviation Regulations as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
94-03-05 Boeing: Amendment 39-8812. Docket 93-NM-128-AD.
Applicability: Model 747-200B, -200C, -300, -400, and -400D
series airplanes equipped with passenger oxygen system reservoir
mask assemblies, having Boeing part numbers 10-60137-152 through -
165 inclusive; certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To ensure the delivery of emergency oxygen through the passenger
oxygen system reservoir mask assemblies, accomplish the following:
(a) For all airplanes: Within 45 days after the effective date
of this AD, revise the FAA-approved maintenance program to require
unrestricted opening of the passenger service unit (PSU) door during
functional testing of the passenger oxygen system.
(b) After accomplishing the requirements of paragraph (a) of
this AD, perform a one-time visual inspection to detect leaks in the
passenger oxygen system reservoir bags, in accordance with Boeing
Telex M-7240-93-1411, dated July 20, 1993, at the time specified in
either paragraph (b)(1) or (b)(2) of this AD, as applicable.
(1) For Model 747-200B, -200C, and -300 series airplanes listed
in Boeing Telex M-7240-93-1411, dated July 20, 1993: Within 15
months after the effective date of this AD.
(2) For Model 747-400 and 747-400D series airplanes listed in
Boeing Telex M-7240-93-1411, dated July 20, 1993: Within 180 days
after the effective date of this AD.
(c) If the masks inflate properly during the inspection required
by paragraph (b) of this AD: No further action is required by this
AD.
(d) If any mask does not inflate properly during the inspection
required by paragraph (b) of this AD: Prior to further flight, mark
the mask assembly and replace it with a new or serviceable mask
assembly, in accordance with Boeing Telex M-7240-93-1411, dated July
20, 1993.
(e) 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, Seattle 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, Seattle ACO.
Note: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(f) Special flight permits may be issued in accordance with FAR
21.197 and 21.199 to operate the airplane to a location where the
requirements of this AD can be accomplished.
(g) The inspection, marking, and replacement shall be done in
accordance with Boeing Telex M-7240-93-1411, dated July 20, 1993.
This incorporation by reference was approved by the Director of the
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part
51. Copies may be obtained from Boeing Commercial Airplane Group,
P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be
inspected at the FAA, Transport Airplane Directorate, 1601 Lind
Avenue, SW., Renton, Washington; or at the Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(h) This amendment becomes effective on March 14, 1994.
Issued in Renton, Washington, on January 26, 1994.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-2182 Filed 2-10-94; 8:45 am]
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