[Federal Register Volume 69, Number 98 (Thursday, May 20, 2004)]
[Rules and Regulations]
[Pages 29049-29054]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-11287]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-291-AD; Amendment 39-13640; AD 2004-10-10]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, and -900 Series Airplanes Equipped With Certain Honeywell Start 
Converter Units

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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

SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 737-600, -700, -700C, -800, and -900 
series airplanes equipped with certain Honeywell start converter units 
(SCU). This amendment requires replacement of the SCU of the auxiliary 
power unit (APU) located in the electrical and electronics (E/E) 
compartment with a new or modified SCU. This action is necessary to 
prevent overheating of the electrical connector of the SCU, which could 
create an ignition source and possible fire in the E/E compartment and 
cause damage to certain electrical wire bundles on the E2-2 shelf. Such 
damage could result in loss of power from the APU generator, failure of 
electrically powered airplane systems, and consequent reduction in the 
ability of the flight crew to control the airplane in certain adverse 
operating conditions. This action is intended to address the identified 
unsafe condition.

DATES: Effective June 24, 2004.

ADDRESSES: Information pertaining to this amendment may be examined at 
the Federal Aviation Administration (FAA), Transport Airplane 
Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Stephen S. Oshiro, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6480; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Boeing Model 737-600, -
700, -700C, -800, and -900 series airplanes equipped with certain 
Honeywell start converter units (SCU) was published in the Federal 
Register on August 9, 2002 (67 FR

[[Page 29050]]

51785). That action proposed to require replacement of certain SCUs 
with new, improved SCUs. The SCUs would be required to be replaced 
according to the Boeing 737-600/700/800/900 Aircraft Maintenance Manual 
(AMM) (the AMM includes procedures for Model 737-700C series 
airplanes).

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Requests To Extend the Compliance Time

    Several commenters request that the compliance time of 18 months 
specified in the notice of proposed rulemaking (NPRM) be extended. The 
following justifications were provided by several commenters in support 
of their request to extend the compliance time from the proposed 18 
months to compliance times ranging from 36 to 60 months.
    One commenter states that, rather than specifying new replacement 
SCUs as described in the ``Cost Impact'' section of the NPRM, the SCUs 
should be described as ``modified.'' The commenter indicates that the 
time for rotation of an SCU through the modification program ranges 
from 40 to 45 days. The commenter expresses concern that the SCU 
manufacturer may not be able to support the proposed 18-month 
compliance time for all affected airplanes. For these reasons, the 
commenter requests that the FAA review any proprietary failure analysis 
of the airplane manufacturer to support a request for extension of the 
compliance time to 42 months.
    One commenter states that it has two spare SCUs to be used in its 
replacement program, and that 54 airplanes of its fleet of 77 Model 
737-800 series airplanes would require replacement. The commenter 
indicates that in order to meet the proposed 18-month compliance time, 
an additional two SCUs would have to be purchased at a cost of 
$420,000. The commenter requests that, to prevent such an expense, the 
compliance time be extended to 36 months.
    One commenter estimates that the time from shipment of a discrepant 
SCU to the SCU manufacturer for modification and acquisition of the 
modified part would be 45 days. The operator states that it would need 
the compliance time extended to 42 months in order to replace all 42 of 
its SCUs.
    Another commenter states that it would need the compliance time 
extended from 18 months due to the large number of SCUs that it will 
have to modify. Additionally, the commenter states that it would need 
the compliance time extended because of the effect the large worldwide 
volume of SCUs will have on the SCU manufacturer's turnaround times. 
Therefore, the commenter prefers that the compliance time be extended 
to 60 months, if possible, but adds that it would be acceptable to 
extend the compliance time to 36 months.

Additional Requests and Reasons for Extending the Compliance Time

    One commenter states that the service history of the Model 737-600, 
-700, and -800 series airplanes has shown that, in most cases, typical 
maintenance and operating procedures have limited the damage caused by 
failed electromagnetic interference (EMI) filter capacitors to the 
capacitors themselves. The commenter states that burning of the wire 
harness appears to occur only in conjunction with a high number of 
auxiliary power unit (APU) restart attempts with an illuminated APU 
fault light. The commenter states further that, of the six incidents 
that were reported as of the date of its comment submittal, only one 
resulted in burning the wire harness. That incident was discovered on 
an airplane that was being introduced into a domestic operator's fleet 
after having been operated by a non-U.S. airline. The commenter 
suspects that the SCU connector failure on that airplane was the result 
of being mishandled possibly by nonqualified personnel as evidenced by 
the 12 to 20 APU restart attempts made with an illuminated APU fault 
light.
    One commenter, the SCU manufacturer, also states that the risk of 
an SCU connector overheat event that progresses to the point where 
aircraft wiring is damaged is considerably reduced if repeated APU 
start attempts are not made. The commenter also advises that it has 
issued a service information letter (SIL) that provides operators of 
the affected airplanes with direction regarding this issue. The 
commenter further states that, although the SIL is not an alternative 
method of compliance with the AD, it does provide additional protection 
against the identified unsafe condition. The commenter further states 
that the two events that occurred since the issuance of the service 
letter (August 16, 2000) were of reduced severity and no damage to the 
airplane wiring was recorded.
    Another commenter, the airplane manufacturer, contends that, even 
in a worst case scenario, the risk to the fleet is minimal because the 
wiring damage does not present a hazard to the airplane or occupants. 
The commenter advises that an analysis was done for each system that 
could be affected and it was found that sufficient redundancy exists 
such that all potential combinations of lost functionality were 
extremely improbable. The commenter further advises that, since the SCU 
automatically removes power for this condition within 300 milliseconds, 
which limits smoke emission, the hazard presented by smoke or the smell 
of burning wires is minimized. Also, the wiring is self extinguishing 
and will not propagate fire and there are no flammable materials in the 
area. The commenter further notes that the electrical/electronic (E/E) 
bay is visually inspected per the zonal inspection program every 18 
months or 4,000 flight cycles, whichever occurs first, for obvious 
unsatisfactory conditions, damage, failures, irregularities and/or 
discrepancies. In addition, the commenter specifies that the smoke 
clearing procedure can be used to eliminate any accumulated smoke and/
or fumes.
    Another commenter requests that the FAA review any failure analysis 
and extend the compliance time from 18 to 42 months.
    The FAA agrees with the commenters' requests to extend the 
compliance time. However, we do not agree with certain commenters' 
justification for extending the compliance time solely on the basis of 
the potential disruption or negative impact on operator flight and 
maintenance schedules, or on other non-safety related aspects of 
airline operations. Those commenters did not address the impact that 
the requested increases in compliance time would have on airplane 
safety, or describe compensatory factors that would mitigate the 
increased exposure of the fleet to the potential unsafe condition as 
the result of a lengthened compliance time.
    In addition, we reviewed the manufacturer's electrical power system 
safety assessment (which includes a failure analysis) for Boeing Model 
737-600, -700, and -800 series airplanes. However, based on that 
review, we have determined that the safety assessment does not address 
all of the specific concerns that prompted the initiation of this AD.
    We do agree that the compliance time may be extended based on the 
capability of the SCU manufacturer to perform the SCU modifications, 
the updated information provided by the airplane manufacturer regarding 
the number of SCU failures to date, the number of SCUs that have yet to 
receive the corrective modifications, and the rate at

[[Page 29051]]

which the SCU manufacturer is currently able to perform the 
modifications.
    Therefore, we have determined that the compliance time may be 
extended from 18 months to 36 months. We consider a 36-month compliance 
time will provide an acceptable level of safety, yet will allow 
operators sufficient time to process the remaining 514 unmodified in-
service and spare SCUs through the SCU manufacturer's modification 
program without undue disruption of airline operations. We have revised 
paragraph (a) of the final rule accordingly.

Request To Revise Paragraph (a) of the NPRM

    One commenter requests that the FAA remove reference to the 
issuance date of Chapter 49-41-61 of the AMM specified in paragraph (a) 
of the NPRM. The commenter notes that by specifying a particular 
issuance date, operators are required to use that specific revision of 
the AMM. The commenter states that if the specific date was removed, 
operators could perform the replacement of the SCU per the latest 
revision of Chapter 49-41-61.
    We do not agree that reference to the particular issuance date of 
Chapter 49-41-61 should be removed. In this case, that particular date 
is the specific revision of the chapter that we have reviewed and 
determined to be an appropriate source of service information for 
accomplishing the replacement of the SCU of the APU. To allow operators 
to use future revisions of Chapter 49-41-61, either we must revise the 
AD to reference specific later revisions, or operators must request 
approval to use later revisions as an alternative method of compliance 
with this AD under the provisions of paragraph (b) of this AD. Since 
the issuance of the NPRM, we have reviewed the current revision of 
Chapter 49-41-61, dated October 10, 2003, and have determined that it 
is also an acceptable source of service information. We have revised 
paragraph (a) of the final rule to specify that replacing the SCU of 
the APU must be accomplished per a method approved by the Manager, 
Seattle Aircraft Certification Office (ACO), FAA. However, we have also 
specified that Chapter 49-41-61, dated June 5, 1998, or dated October 
10, 2003, is an approved method for the accomplishment of the 
requirements of paragraph (a) of this final rule.

Request To Revise Paragraph (b) of the NPRM

    Two commenters request that the compliance time specified in 
paragraph (b) of the NPRM be revised to match the compliance time 
specified in paragraph (a) of the NPRM for replacement of the affected 
SCUs. The commenters state that it is unrealistic to specify that, ``as 
of the effective date of the AD, no person shall install on any 
airplane * * *,'' due to the turnaround time to remove, modify, and 
install the SCUs (discussed in comments previously).
    We acknowledge that, because of a possible delay in modifying the 
SCUs, the compliance time of the ``spares'' paragraph (b) in the NPRM 
is unrealistic. We consider that a condition could occur where 
operators remove the SCUs for modification and no modified spares are 
available for installation, effectively, grounding the airplane. 
Generally, the purpose of the ``spares'' paragraph is to ensure that 
unmodified or identified ``unsafe'' parts are not installed/reinstalled 
on airplanes, and specifically, prior to the compliance time specified 
for modification in paragraph (a) of the final rule. Therefore, there 
is no reason to include a ``spares'' paragraph in this AD with a 
compliance time that is identical to the threshold compliance time 
required by paragraph (a) of this AD. We have determined that, in this 
case, removal of the prohibition to install certain SCU part numbers as 
of the effective date of the AD is warranted, and we have removed 
paragraph (b) from the final rule and reidentified subsequent 
paragraphs accordingly.

Request To Withdraw the NPRM

    One commenter states that, given the proven service experience of 
the Model 737 (NG) series airplanes and the limited number of burnt 
harnesses (one) reported, continuing to upgrade the SCUs at the normal 
attrition rate will provide an adequate level of safety. We infer that 
the commenter is requesting that we withdraw the NPRM.
    We do not agree. We consider the SCU connector failures to be a 
safety issue of sufficient significance to warrant the removal, 
modification, and replacement of the SCUs via regulatory requirement 
rather than by relying on passive means such as attrition. Such 
reliance on attrition does not ensure that the affected airplanes will 
receive appropriately modified SCUs in a timely manner, or at all.

Request To Revise the Airplane Flight Manual (AFM)

    One commenter suggests that flight safety can be best preserved by 
amending the AFM to limit the number of start attempts with a 
consecutive fault illumination to a total of three including two 
restarts. The commenter states that requiring such an AFM limitation 
would be a more immediate action than waiting for the 18-month 
compliance time to replace/modify the SCUs, and would ensure that a 
burning harness would not occur in flight. The commenter notes that the 
Non-Normal Procedures Section of the Model 737 series airplane AFM 
currently allows restart attempts five minutes after the APU switch is 
placed in the ``OFF'' position and the APU fault light extinguishes.
    We do not agree that adding a requirement to revise the AFM is 
appropriate at this time. An AFM limitation might reduce the short-term 
likelihood of filter capacitor failures, however, the limitation would 
be difficult to define since the number of repetitive start attempts 
after which the filter capacitors have been degraded to the point of 
failure has not been conclusively determined. Furthermore, an AFM 
limitation would not address long-term exposure of the fleet to the 
potential unsafe condition, since the cumulative effects of non-
consecutive APU restart attempts on the filter capacitors also has not 
been determined. No change to the final rule is necessary.

Request To Clarify the ``Airworthiness Directives'' Heading

    One commenter, the SCU manufacturer, requests that the 
``Airworthiness Directives'' heading be revised. The commenter suggests 
that the heading be revised to add the word ``certain,'' as follows: 
``Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800, 
and -900 Series Airplanes Equipped'' with ``Certain'' Honeywell Start 
Converter Units.'' The commenter explains that adding the word 
``certain,'' clarifies that not ``all'' SCU part numbers are affected 
on the applicable airplanes.
    We agree with the commenter's request and have revised the heading 
accordingly.

Request To Revise Wording Describing the Action To Replace

    One commenter, the SCU manufacturer, requests that the wording 
describing the replacement of the SCU with ``a new, improved SCU'' be 
revised to read, ``a modified SCU.'' The commenter indicates that, by 
specifying

[[Page 29052]]

``a modified SCU,'' operators would not be mislead into thinking that 
the SCU manufacturer would replace the existing SCU at no charge to the 
operators with SCUs that may be manufactured with technological 
advances over and above the SCUs specified in the NPRM.
    We understand the commenter's position and agree that clarification 
is necessary. Since certain ``new'' production SCU part numbers 
incorporate design features that preclude the unsafe condition, we 
consider those ``new'' SCU part numbers to be acceptable replacements, 
and the table titled ``SCU Part Numbers'' of the final rule identifies 
the SCU part numbers that are acceptable as replacements. Therefore, we 
have revised the ``Summary'' section of the final rule to specify that 
replacement shall be with ``a new or modified SCU.'' Since the wording 
specified in the ``Supplementary Information'' section of the NPRM that 
discussed replacement with ``a new, improved SCU'' does not reappear in 
the final rule, it is not necessary to revise the final rule further in 
this regard.

Request To Revise the ``Discussion'' Section of the NPRM

    One commenter, the SCU manufacturer, requests that the 
``Discussion'' section of the NPRM be revised to specify the number of 
incidents and APU operating hours. The commenter suggests that the FAA 
state that there have been six reported incidents of SCU ARINC 
connector overheating in approximately 5 million APU operating hours 
(to September 6, 2002), and that two of these events showed visual 
damage to adjacent electrical wire bundles on certain Boeing Model 737-
700 and -800 series airplanes. The commenter states that such revision 
of the ``Discussion'' section is necessary to minimize the possibility 
of misunderstanding the scope of the issue.
    We do not agree that the ``Discussion'' section of the NPRM should 
be revised. We acknowledge that the number of incidents of SCU 
connector failure that resulted in the APU generator failures might 
provide additional useful background information. However, we note that 
we have recently received updated information from the airplane 
manufacturer regarding additional SCU connector failure events. In 
fact, as of October 3, 2003, the total number of SCU connector failure 
events had risen from six (as reported by the commenter) to ten. The 
number of events in which heat damage propagated to electrical wiring 
external to the SCU also increased from two to three. As discussed 
previously, the ``Discussion'' section does not reappear in the final 
rule. Therefore, no change to the final rule is necessary in this 
regard.

Request To Add a Note to ``Discussion'' Section

    The same commenter, the SCU manufacturer, requests that a note be 
added at the end of the ``Discussion'' section of the NPRM to specify 
that during the investigation it was recognized that the extent of heat 
damage resulting from the event is proportional to the number of 
restarting attempts performed with an already failed unit. The 
commenter advises that Honeywell Service Information Letter (SIL) SIL 
49-C-139 was issued to instruct the operator to recognize the fault 
indication and cease further starting attempts until troubleshooting 
can be performed. The commenter also states that events that occurred 
after the issue of SIL (2 events) were of reduced severity, and no 
damage to aircraft wiring was recorded. The commenter contends that 
observing the procedures described in the SIL effectively limits the 
extent of overheat damage.
    We do not agree that the ``Discussion'' section of the NPRM should 
be revised per the commenter. No data has been submitted to the FAA to 
support the statement that the extent of heat damage resulting from an 
event is proportional to the number of restart attempts with an already 
failed unit. We do acknowledge, however, potential safety benefits of 
recognizing SCU failure indications in conjunction with terminating 
subsequent APU start attempts until appropriate maintenance and 
troubleshooting has been performed, as recommended in the above 
referenced Honeywell SIL. We consider that implementation of the 
procedures described in the Honeywell SIL until replacement of the SCUs 
may reduce the likelihood of SCU connector failures during the 
compliance period. As discussed previously, the ``Discussion'' section 
does not reappear in the final rule. Therefore, no change is necessary 
to the final rule in this regard.

Request To Revise Estimated Number of Affected Airplanes

    One commenter, the SCU manufacturer, requests that the estimated 
number of airplanes currently affected by the NPRM be revised. The 
commenter states that it has completed modification of 198 SCU units 
since it submitted the original estimate of affected airplanes.
    We agree that the estimated number of affected airplanes can be 
reduced. We also received updated information from the airplane 
manufacturer that confirmed a reduction of the number of affected 
airplanes. Therefore, we have revised the Cost Impact section of the 
final rule accordingly. See ``Editorial Change to Labor Rate Estimate'' 
paragraph below for other changes to the Cost Impact paragraph of this 
final rule.

Request To Revise SCU Part Numbers Specified in Paragraph (a) of the 
NPRM

    One commenter, the SCU manufacturer, requests that the second 
column of the table in paragraph (a) of the NPRM be removed and 
replaced with certain other ``acceptable'' replacement part numbers. 
The commenter states that the table in paragraph (a) of the NPRM could 
be misleading by indicating that affected part numbers can only be 
replaced with the corresponding number in the right column. The 
commenter further states that listing the acceptable part numbers 
separately would clarify the requirement and indicate all acceptable 
SCU part numbers that may be installed on the airplane.
    We agree that clarification is necessary. Based on information 
received from the airplane manufacturer, we have determined that SCUs 
having part numbers 1151858-241 (of any series) are not interchangeable 
with SCUs having part numbers 1152426-245 (of any series) or 1152466-
250 (of any series). However, all SCUs having part numbers 1152426-245 
and 1152466-250 of any series are interchangeable. Therefore, to 
prevent confusion regarding the selection of appropriate replacement 
SCUs, the table in paragraph (a) of the final rule has been revised to 
illustrate this clarification.

Conclusion

    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.

Changes to 14 CFR Part 39/Effect on the AD

    On July 10, 2002, the FAA issued a new version of 14 CFR part 39 
(67 FR 47997, July 22, 2002), which governs the FAA's airworthiness 
directives system. The regulation now includes material that relates to 
altered products, special flight permits, and alternative methods

[[Page 29053]]

of compliance. However, for clarity and consistency in this final rule, 
we have retained the language of the NPRM regarding that material.

Editorial Change to Labor Rate Estimate

    After the NPRM was issued, we reviewed the figures we use to 
calculate the labor rate to do the required actions. To account for 
various inflationary costs in the airline industry, we find it 
appropriate to increase the labor rate used in these calculations from 
$60 per work hour to $65 per work hour. The economic impact 
information, below, has been revised to reflect this increase in the 
specified hourly labor rate.

Cost Impact

    There are approximately 403 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 250 airplanes of U.S. registry 
will be affected by this AD, that it will take approximately 4 work 
hours per airplane to accomplish the required actions, and that the 
average labor rate is $65 per work hour. Required parts will be 
provided by the parts manufacturer at no cost to operators. Based on 
these figures, the cost impact of the AD on U.S. operators is estimated 
to be $65,000, or $260 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the requirements of this AD 
action, and that no operator would accomplish those actions in the 
future if this AD were not adopted. The cost impact figures discussed 
in AD rulemaking actions represent only the time necessary to perform 
the specific actions actually required by the AD. These figures 
typically do not include incidental costs, such as the time required to 
gain access and close up, planning time, or time necessitated by other 
administrative actions.

Regulatory Impact

    The regulations adopted herein 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. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    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, Safety.

Adoption of the Amendment

0
Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

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. Section 39.13 is amended by adding the following new airworthiness 
directive:

2004-10-10 Boeing: Amendment 39-13640. Docket 2001-NM-291-AD.

    Applicability: Model 737-600, -700, -700C, -800, and -900 series 
airplanes; certificated in any category; equipped with start 
converter units (SCUs) having Honeywell part number (P/N) 1151858-
241, Series 1 through 9 inclusive, or P/N 1152426-245, Series 1 
through 6 inclusive.

    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 (b) 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 overheating of the electrical connector of the SCU, 
which could create an ignition source and possible fire in the 
electrical and electronics (E/E) compartment and cause damage to 
certain electrical wire bundles on the E2-2 shelf, accomplish the 
following:

Replacement

    (a) Within 36 months after the effective date of this AD: 
Replace the SCU of the auxiliary power unit located in the E/E 
compartment per a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA. Boeing 737-600/700/800/900 
Maintenance Manual, Chapter 49-41-61, dated June 5, 1998; and 
Aircraft Maintenance Manual, Chapter 49-41-61, dated October 10, 
2003, are approved methods of compliance with the requirements of 
this paragraph. Replace the applicable SCU listed in the ``Existing 
Honeywell P/N'' column below, with the corresponding SCU listed in 
the ``Replacement Honeywell P/N'' column below, as follows:

SCU Part Numbers

------------------------------------------------------------------------
         Existing Honeywell P/N             Replacement Honeywell P/N
------------------------------------------------------------------------
1151858-241, of any series 1 through 9   1151858-241, series 10 or
 inclusive.                               1151858-241, series 11 or
                                          1151858-241, series 12.
1152426-245, of any series 1 through 6   1152426-245, series 7 or
 inclusive.                               1152426-245, series 8 or
                                          1152466-250, series 1 or
                                          1152466-250, series 2 or
                                          1152466-250, series 3.
------------------------------------------------------------------------

Alternative Methods of Compliance

    (b) 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 ACO, FAA. 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (c) Special flight permits may be issued in accordance with 
Sec.  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.

Effective Date

    (d) This amendment becomes effective on June 24, 2004.


[[Page 29054]]


    Issued in Renton, Washington, on May 10, 2004.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-11287 Filed 5-19-04; 8:45 am]
BILLING CODE 4910-13-P