# AD 2010-21-16: Hydraulic Power

- Type: Airworthiness directive
- Status: Current
- Products: Boeing MD-90-30
- Effective: November 18, 2010
- Published: October 14, 2010, 75 FR 63039–63040
- Issued: October 1, 2010
- Issued as: Final rule
- Supersedes: [AD 2009-07-04](https://openairdocs.org/ad/2009-07-04)
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- ATA chapter: 29 · Hydraulic power
- Amendment: 39-16476
- Docket: FAA-2010-0554 (https://www.regulations.gov/docket/FAA-2010-0554)
- Project: 2010-NM-082-AD
- Registered aircraft: 5 may be affected, by airframe or engine model (OpenAirDocs)
- Official PDF: https://openairdocs.org/files/sha256/9f/ff/9fff2c64ccadce28b606aedeba644079964d85957db462b3e4047f88a50370d8 (from https://www.govinfo.gov/content/pkg/FR-2010-10-14/pdf/2010-25440.pdf)
- Federal Register: https://www.federalregister.gov/documents/2010/10/14/2010-25440/airworthiness-directives-mcdonnell-douglas-corporation-model-md-90-30-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/562291E6AE57FCD4862577BC00578215.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/2010-21-16

## Summary

We are superseding an existing airworthiness directive (AD) for the products listed above. That AD currently requires modifying the auxiliary hydraulic power system (including doing all applicable related investigative and corrective actions). This new AD requires these same actions, using corrected service information. This AD was prompted by fuel system reviews conducted by the manufacturer, as well as reports of electrically shorted wires in the right wheel well and evidence of arcing on the auxiliary hydraulic pump power cables, which are routed within the tire burst area. We are issuing this AD to prevent electrically shorted wires or arcing at the auxiliary hydraulic pump power cables, which could result in a fire in the wheel well. We are also issuing this AD to reduce the potential of an ignition source adjacent to the fuel tanks, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

## 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 removing airworthiness directive (AD) 2009-07-04, Amendment 39-15863 (74 FR 14460, March 31, 2009), and adding the following new AD:

2010-21-16 McDonnell Douglas Corporation: Amendment 39-16476; Docket No. FAA-2010-0554; Directorate Identifier 2010-NM-082-AD.

### (a) Effective Date

  (a) This airworthiness directive (AD) is effective November 18, 2010.

### (b) Affected ADs

  (b) This AD supersedes AD 2009-07-04, Amendment 39-15863.

### (c) Applicability

  (c) This AD applies to McDonnell Douglas Corporation Model MD-90-30 airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin MD90-29A021, Revision 2, dated March 16, 2010.

### (d) Subject

  (d) Air Transport Association (ATA) of America Code 29: Hydraulic Power.

### (e) Unsafe Condition

  (e) This AD results from fuel system reviews conducted by the manufacturer, as well as reports of electrically shorted wires in the right wheel well and evidence of arcing on the auxiliary hydraulic pump power cables, which are routed within the tire burst area. The Federal Aviation Administration is issuing this AD to prevent electrically shorted wires or arcing at the auxiliary hydraulic pump power cables, which could result in a fire in the wheel well. We are also issuing this AD to reduce the potential of an ignition source adjacent to the fuel tanks, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

### (f) Compliance

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

### (g) Replacement

  (g) Within 18 months after the effective date of this AD, modify the auxiliary hydraulic power system, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-29A021, Revision 2, dated March 16, 2010. Do all applicable related investigative and corrective actions before further flight.

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

  (h)(1) The Manager, Los Angeles Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Ken Sujishi, Aerospace Engineer, Cabin Safety/Mechanical and Environmental Systems Branch, ANM-150L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5353; fax (562) 627-5210.

  (2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

### (i) Related Information

    (i) For more information about this AD, contact Ken Sujishi, Aerospace Engineer, Cabin Safety/Mechanical and Environmental Systems Branch, ANM-150L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5353; fax (562) 627-5210; e-mail ken.sujishi@faa.gov.

### (j) Material Incorporated by Reference

  (j) You must use the service information contained in Boeing Alert Service Bulletin MD90-29A021, Revision 2, dated March 16, 2010, 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 Boeing Alert Service Bulletin MD90-29A021, Revision 2, dated March 16, 2010, under 5 U.S.C. 552(a) and 1 CFR part 51.

  (2) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, 3855 Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-0001; telephone 206-544-5000, extension 2; fax 206-766-5683; e-mail dse.boecom@boeing.com; Internet https://www.myboeingfleet.com.

  (3) You may review copies of the service information at the FAA, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

  (4) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at an NARA facility, 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 November 18, 2010.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of November 18, 2010.

### Addresses

For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, 3855 Lakewood Boulevard, MC D800-0019, Long Beach, California 90846-0001; telephone 206-544-5000, extension 2; fax 206-766-5683; e-mail dse.boecom@boeing.com; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

### For further information contact

Ken Sujishi, Aerospace Engineer, Cabin Safety/Mechanical and Environmental Systems Branch, ANM-150L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5353; fax (562) 627-5210; e-mail ken.sujishi@faa.gov.

### Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede airworthiness directive (AD) 2009-07-04, amendment 39-15863 (74 FR 14460, March 31, 2009). That AD applies to the specified products. The NPRM published in the Federal Register on June 28, 2010 (75 FR 36577). That NPRM proposed to continue to require modifying the auxiliary hydraulic power system (including doing all applicable related investigative and corrective actions), using corrected service information.

### Comments

We gave the public the opportunity to participate in developing this AD. We received no comments on the NPRM or on the determination of the cost to the public.

### Conclusion

We reviewed the relevant data and determined that air safety and the public interest require adopting the AD as proposed.

### Costs of Compliance

We estimate that this AD affects 21 airplanes of U.S. registry. We estimate the following costs to comply with this AD:

*Estimated Costs*

| Action | Labor cost | Parts cost | Cost per product | Cost on U.S. operators |
| --- | --- | --- | --- | --- |
| Modification | Between 4 and 11 work-hours × $85 per hour = Between $340 and $935 | Up to $4,870 | Between $5,210 and $5,805 | Between $109,410 and $121,905. |

### 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),

  (3) Will not affect intrastate aviation in Alaska, and

  (4) 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.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A6WE](https://openairdocs.org/tcds/A6WE): The Boeing Company; names 1 of 25 models: MD-90-30

## 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: 5 (5 by airframe model, 0 by engine model)
- Makers: Mcdonnell Douglas 3, Boeing 2

Models with the most aircraft:

- [Mcdonnell Douglas MD-90-30](https://openairdocs.org/model/mcdonnell-douglas-md-90-30): 3 aircraft (airframe model)
- [Boeing MD-90-30](https://openairdocs.org/model/boeing-md-90-30): 2 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/2010-21-16/models.md
Every aircraft: https://openairdocs.org/ad/2010-21-16/aircraft.md

## Related documents

- [AD 2009-07-04](https://openairdocs.org/ad/2009-07-04) (historical): Auxiliary hydraulic power system · McDonnell Douglas MD-90-30. Effective May 5, 2009. Replaced by this AD
- [Proposed rule FAA-2010-0554](https://openairdocs.org/proposed/FAA-2010-0554): Notice of proposed rulemaking (NPRM), published Jun 28, 2010

Its text cites no advisory circulars or STCs.

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