# AD 2008-08-25: Main equipment center

- Type: Airworthiness directive
- Status: Historical
- Products: Boeing 747-400 Series and 747-400F Series
- Effective: May 27, 2008
- Published: April 21, 2008, 73 FR 21240–21242
- Issued: April 7, 2008
- Issued as: Final rule
- Superseded by: [AD 2014-05-31](https://openairdocs.org/ad/2014-05-31)
- Product type: Aircraft, Large airplane
- Amendment: 39-15479
- Docket: FAA-2006-26726 (https://www.regulations.gov/docket/FAA-2006-26726)
- Project: 2006-NM-205-AD
- Registered aircraft: 53 may be affected, by airframe or engine model (OpenAirDocs)
- Official PDF: https://openairdocs.org/files/sha256/fa/96/fa963a958c24d12adcb48045215da04124e8c3d18217898f9b1290e255d6cbdc (from https://www.govinfo.gov/content/pkg/FR-2008-04-21/pdf/E8-8327.pdf)
- Federal Register: https://www.federalregister.gov/documents/2008/04/21/E8-8327/airworthiness-directives-boeing-model-747-400f-and--400-series-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/830EC41528D5BFFE862574320061CB0D.0001
- DRS record last changed: August 7, 2025
- Page: https://openairdocs.org/ad/2008-08-25

## Summary

We are adopting a new airworthiness directive (AD) for certain Boeing Model 747-400F and -400 series airplanes. This AD requires installing drains and drain tubes to eliminate water accumulation in the dripshield above the M826 Card File in the main equipment center. This AD results from a report that water from the dripshield entered the card file and damaged a circuit card, causing the AFT CARGO FIRE MSG message to be illuminated and resulting in an air turn back. We are issuing this AD to prevent water from entering the card file and damaging a circuit card. Failure of one or more of the 15 fuel system circuit cards in the card file could cause loss of fuel management, which could cause unavailability of fuel. Failure of one or more of the 35 fire detection circuit cards could cause a false message of a fire, or no message of a fire when there is a fire.

## The airworthiness directive

### Adoption of the Amendment

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

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new AD:

2008-08-25 Boeing: Amendment 39-15479. Docket No. FAA-2006-26726; Directorate Identifier 2006-NM-205-AD.

### (a) Effective Date

  (a) This airworthiness directive (AD) is effective May 27, 2008.

### (b) Affected ADs

  (b) None.

### (c) Applicability

  (c) This AD applies to Boeing Model 747-400F airplanes as identified in Boeing Alert Service Bulletin 747-25A3370, Revision 1, dated April 27, 2006; and Model 747-400 series airplanes as identified in Boeing Alert Service Bulletin 747-25A3526, dated November 13, 2007; certificated in any category.

### (d) Unsafe Condition

  (d) This AD results from a report that water from the dripshield entered the card file and damaged a circuit card, causing the AFT CARGO FIRE MSG message to be illuminated and resulting in an air turn back. We are issuing this AD to prevent water from entering the card file and damaging a circuit card. Failure of one or more of the 15 fuel system circuit cards in the card file could cause loss of fuel management, which could cause unavailability of fuel. Failure of one or more of the 35 fire detection circuit cards could cause a false message of a fire, or no message of a fire when there is a fire.

### (e) 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.

### (f) Installation

  (f) Within 24 months after the effective date of this AD, install two drains and drain tubes in the dripshield above the M826 Card File over the nose wheel left side in the main equipment center at station 400, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-25A3370, Revision 1, dated April 27, 2006 (for Model 747-400F series airplanes); or Boeing Alert Service Bulletin 747-25A3526, dated November 13, 2007 (for Model 747-400 series airplanes).

### (g) Installation According to Previous Issue of Service Bulletin

  (g) Installing the drains and drain tubes is also acceptable for compliance with the requirements of paragraph (f) of this AD if done before the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-25A3370, dated September 8, 2005.

### (h) Alternative Methods of Compliance (AMOCs)

  (h)(1) The Manager, Seattle Aircraft Certification Office, 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 § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

### (i) Material Incorporated by Reference

    (i) You must use Boeing Alert Service Bulletin 747-25A3370, Revision 1, dated April 27, 2006; or Boeing Alert Service Bulletin 747-25A3526, dated November 13, 2007; as applicable; to do the actions required by this AD, unless the AD specifies otherwise.

  (1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.

  (2) For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

  (3) You may review copies of the service information incorporated by reference at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

## Rule preamble

### Dates

This AD is effective May 27, 2008.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of May 27, 2008.

### Addresses

For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

### For further information contact

Marcia Smith, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6484; fax (425) 917-6590.

### Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to certain Boeing Model 747-400F series airplanes. That NPRM was published in the Federal Register on January 8, 2007 (72 FR 664). That NPRM proposed to require installing drains and drain tubes to eliminate water accumulation in the dripshield above the M826 Card File in the main equipment center.

### Comments

We gave the public the opportunity to participate in developing this AD. We considered the comment received from the one commenter.

### Request To Revise the Applicability Language and To Add New Service Information

Boeing requests that all occurrences of the phrase “certain 747-400F series airplanes” be changed to “certain 747-400F and certain 747-400BCF series airplanes.” Boeing states that this change will clarify the affected models for operators, and that the wording of the proposed applicability statement, “747-400F series,” does not include the Model 747-400BCF (Boeing converted freighter) airplanes. Boeing states that it is revising the existing service bulletin referred to in the NPRM to include some early Model 747-400BCF airplanes.

We partially agree. We have determined that these airplanes are also subject to the identified unsafe condition addressed by this AD. Therefore, we agree to revise the applicability language of this AD to include these airplanes; however, we do not agree to use the language suggested by Boeing. Section XIII., “747-400SF Major Design Change,” of the type certificate data sheet for Boeing Model 747 airplanes states that the Model 747-400SF (special freighter), optionally known as Model 747-400BCF, remains as Model 747-400 series airplanes for documentation purposes and with regard to the applicability of ADs. Therefore, we have revised the applicability language in the preamble of this final rule to specify “certain Boeing Model 747-400F and 747-400 series airplanes.” However, none of the airplanes added to the applicability statement of this AD are on the U.S. Register, therefore additional notice and opportunity for public comment before issuing this AD are unnecessary. We have also revised the applicability statement of this final rule to refer to Boeing Alert Service Bulletin 747-25A3526, dated November 13, 2007 (described below), for Model 747-400 series airplanes.

Since we issued the NPRM, Boeing has issued Alert Service Bulletin 747-25A3526 to address the identified unsafe condition on certain Model 747-400 series airplanes. This service bulletin includes procedures that are essentially the same as those described in Boeing Alert Service Bulletin 747-25A3370, Revision 1, dated April 27, 2006 (referred to in the NPRM as the appropriate source of service information for doing the proposed actions for Model 747-400F airplanes), except that it also includes moving the P402 panel. As we stated previously, we have added Boeing Alert Service Bulletin 747-25A3526 to this final rule.

### Conclusion

We reviewed the relevant data, considered the comment received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD.

### Change to Costs of Compliance Section of the NPRM

We have revised this final rule to update the number of airplanes (representing the 747-400 series airplanes) in the worldwide fleet. None of the airplanes added to the applicability statement of this AD are on the U.S. Register, so the figures in the estimated costs table remain unchanged.

### Costs of Compliance

There are about 130 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this AD.

*Estimated Costs*

| Action | Work hours | Average labor rate per hour | Parts | Cost per airplane | Number of U.S.-registered airplanes | Fleet cost |
| --- | --- | --- | --- | --- | --- | --- |
| Installation | 8 | $80 | $822 | $1,462 | 21 | $30,702 |

### 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

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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A20WE](https://openairdocs.org/tcds/A20WE): The Boeing Company; names 2 of 14 models: 747-400F Series, 747-400 Series

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 53 (53 by airframe model, 0 by engine model)
- Makers: Boeing 53

Models with the most aircraft:

- [Boeing 747-446](https://openairdocs.org/model/boeing-747-446): 10 aircraft (airframe model)
- [Boeing 747-422](https://openairdocs.org/model/boeing-747-422): 8 aircraft (airframe model)
- [Boeing 747-412](https://openairdocs.org/model/boeing-747-412): 5 aircraft (airframe model)
- [Boeing 747-400F](https://openairdocs.org/model/boeing-747-400f): 4 aircraft (airframe model)
- [Boeing 747-409](https://openairdocs.org/model/boeing-747-409): 4 aircraft (airframe model)
- [Boeing 747-481F](https://openairdocs.org/model/boeing-747-481f): 3 aircraft (airframe model)
- [Boeing 747-409F](https://openairdocs.org/model/boeing-747-409f): 3 aircraft (airframe model)
- [Boeing 747-481](https://openairdocs.org/model/boeing-747-481): 3 aircraft (airframe model)
- [Boeing 747-428F](https://openairdocs.org/model/boeing-747-428f): 3 aircraft (airframe model)
- [Boeing 747-443](https://openairdocs.org/model/boeing-747-443): 2 aircraft (airframe model)
- [Boeing 747-438](https://openairdocs.org/model/boeing-747-438): 2 aircraft (airframe model)
- [Boeing 747-428](https://openairdocs.org/model/boeing-747-428): 2 aircraft (airframe model)
- [Boeing 747-400](https://openairdocs.org/model/boeing-747-400): 1 aircraft (airframe model)
- [Boeing 747-412F](https://openairdocs.org/model/boeing-747-412f): 1 aircraft (airframe model)
- [Boeing 747-467F](https://openairdocs.org/model/boeing-747-467f): 1 aircraft (airframe model)
- [Boeing 747-451](https://openairdocs.org/model/boeing-747-451): 1 aircraft (airframe model)

All 16 models: https://openairdocs.org/ad/2008-08-25/models.md
Every aircraft: https://openairdocs.org/ad/2008-08-25/aircraft.md

## Related documents

- [AD 2014-05-31](https://openairdocs.org/ad/2014-05-31): Equipment/Furnishings · Boeing 747-400 Series and 747-400F Series. Effective May 2, 2014. Supersedes this AD
- [Proposed rule FAA-2006-26726](https://openairdocs.org/proposed/FAA-2006-26726): Notice of proposed rulemaking (NPRM), published Jan 8, 2007

Its text cites no advisory circulars or STCs.

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