Federal Register / Vol. 75, No. 133 / Tuesday, July 13, 2010 / Rules and Regulations 39795 

TABLE 7—ALL MATERIAL INCORPORATED BY REFERENCE

Airbus— Revision— Dated— 

AOT A330–24A3042 ........................................................................................................................................... 02 April 12, 2007. 

AOT A330–24A3044 ........................................................................................................................................... 03 May 26, 2008. 

AOT A340–24A4056 ........................................................................................................................................... 02 April 12, 2007. 

AOT A340–24A4057 ........................................................................................................................................... 03 December 20, 

2007. 

AOT A340–24–A5020 ......................................................................................................................................... 02 April 12, 2007. 

AOT A340–24A5021 ........................................................................................................................................... 02 December 20, 

2007. 

Mandatory Service Bulletin A330–24–3045 ........................................................................................................ 01 October 1, 2008. 

Mandatory Service Bulletin A340–24–4058 ........................................................................................................ 01 October 1, 2008. 

Mandatory Service Bulletin A340–24–5022 ........................................................................................................ 01 November 27, 

2008. 

(The AOT document number, revision level, and date are indicated on only page 1 of these documents.) 

(1) The Director of the Federal Register 

approved the incorporation by reference of 

the service information contained in Table 8 

of this AD under 5 U.S.C. 552(a) and 1 CFR 

part 51. 

TABLE 8—NEW MATERIAL INCORPORATED BY REFERENCE

Airbus— Revision— Dated— 

AOT A330–24A3044 ........................................................................................................................................... 03 May 26, 2008. 

AOT A340–24A4057 ........................................................................................................................................... 03 December 20, 

2007. 

AOT A340–24A5021 ........................................................................................................................................... 02 December 20, 

2007. 

Mandatory Service Bulletin A330–24–3045 ........................................................................................................ 01 October 1, 2008. 

Mandatory Service Bulletin A340–24–4058 ........................................................................................................ 01 October 1, 2008. 

Mandatory Service Bulletin A340–24–5022 ........................................................................................................ 01 November 27, 

2008. 

(2) The Director of the Federal Register 

previously approved the incorporation by 

reference of the service information 

contained in Table 9 of this AD on June 26, 

2007 (72 FR 31973, June 11, 2007). 

TABLE 9—MATERIAL PREVIOUSLY INCORPORATED BY REFERENCE

Airbus all operators telex— Revision 

level— Dated— 

A330–24A3042 ......................................................................................................................................................... 02 April 12, 2007. 

A340–24A4056 ......................................................................................................................................................... 02 April 12, 2007. 

A340–24A5020 ......................................................................................................................................................... 02 April 12, 2007. 

(3) For service information identified in 

this AD, contact Airbus SAS—Airworthiness 

Office—EAL, 1 Rond Point Maurice Bellonte, 

31707 Blagnac Cedex, France; telephone +33 

5 61 93 36 96; fax +33 5 61 93 45 80, e-mail: 

airworthiness.A330-A340@airbus.com; 

Internet http://www.airbus.com. 

(4) You may review copies of the 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. 

(5) 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 NARA, call 202–741–6030, or go 

to: http://www.archives.gov/federal_register/ 

code_of_federal_regulations/ 

ibr_locations.html. 

Issued in Renton, Washington, June 23, 

2010. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2010–16181 Filed 7–12–10; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2010–0684; Directorate 

Identifier 2010–CE–031–AD; Amendment 

39–16360; AD 2010–14–15] 

RIN 2120–AA64 

Airworthiness Directives; Aircraft 

Industries a.s. (Type Certificate G60EU 

Previously Held by LETECKE ́ ZA ́ VODY 

a.s. and LET Aeronautical Works) 

Model L–13 Blanik Gliders 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 


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39796 Federal Register / Vol. 75, No. 133 / Tuesday, July 13, 2010 / Rules and Regulations 

ACTION: Final rule; request for 

comments. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for the 

products listed above. This AD results 

from mandatory continuing 

airworthiness information (MCAI) 

issued by the aviation authority of 

another country to identify and correct 

an unsafe condition on an aviation 

product. The MCAI describes the unsafe 

condition as: 

A fatal accident occurred to a L–13 

BLANI ́K sailplane, in which the main spar of 

the right wing failed near the root due to 

positive load. The right wing detached from 

the aircraft and the pilots lost control of the 

sailplane. 

The preliminary investigation has revealed 

that the fracture may have been due to 

fatigue. 

This AD requires actions that are 

intended to address the unsafe 

condition described in the MCAI. 

DATES: This AD becomes effective July 

19, 2010. 

On July 19, 2010, the Director of the 

Federal Register approved the 

incorporation by reference of certain 

publications listed in this AD. 

We must receive comments on this 

AD by August 27, 2010. 

ADDRESSES: You may send comments by 

any of the following methods: 

• Federal eRulemaking Portal: Go to 

http://www.regulations.gov. Follow the 

instructions for submitting comments. 

• Fax: (202) 493–2251. 

• Mail: U.S. Department of 

Transportation, Docket Operations, M– 

30, West Building Ground Floor, Room 

W12–140, 1200 New Jersey Avenue, SE., 

Washington, DC 20590. 

• Hand Delivery: U.S. Department of 

Transportation, Docket Operations, M– 

30, West Building Ground Floor, Room 

W12–140, 1200 New Jersey Avenue, SE., 

Washington, DC 20590, between 9 a.m. 

and 5 p.m., Monday through Friday, 

except Federal holidays. 

Examining the AD Docket 

You may examine the AD docket on 

the Internet at http:// 

www.regulations.gov; or in person at the 

Docket Management Facility between 9 

a.m. and 5 p.m., Monday through 

Friday, except Federal holidays. The AD 

docket contains this AD, the regulatory 

evaluation, any comments received, and 

other information. The street address for 

the Docket Office (telephone (800) 647– 

5527) is in the ADDRESSES section. 

Comments will be available in the AD 

docket shortly after receipt. 

FOR FURTHER INFORMATION CONTACT: Greg 

Davison, Aerospace Engineer, FAA, 

Small Airplane Directorate, 901 Locust, 

Room 301, Kansas City, Missouri 64106; 

telephone: (816) 329–4130; fax: (816) 

329–4090. 

SUPPLEMENTARY INFORMATION: 

Discussion 

The European Aviation Safety Agency 

(EASA), which is the Technical Agent 

for the Member States of the European 

Community, has issued Emergency AD 

No.: 2010–0122–E, dated June 23, 2010 

(referred to after this as ‘‘the MCAI’’), to 

correct an unsafe condition for the 

specified products. The MCAI states: 

A fatal accident occurred to a L–13 

BLANI ́K sailplane, in which the main spar of 

the right wing failed near the root due to 

positive load. The right wing detached from 

the aircraft and the pilots lost control of the 

sailplane. 

The preliminary investigation has revealed 

that the fracture may have been due to 

fatigue. 

The Emergency AD 2010–0119–E required 

immediate inspection of the main spar at the 

root of the wing to detect fatigue cracking 

and the accomplishment of the relevant 

corrective actions as necessary. In addition, 

this AD 2010–0119–E imposed operational 

limitations. This AD retains the requirements 

of AD 2010–0119–E, which is superseded, 

and extends the applicability to L–13 A 

BLANI ́K sailplanes. 

The requirements of this AD are 

considered as interim action to immediately 

address this unsafe condition. If, as a result 

of the on-going investigation, a terminating 

action is later identified, further mandatory 

actions might be considered. 

You may obtain further information by 

examining the MCAI in the AD docket. 

Relevant Service Information 

Aircraft Industries a.s. has issued 

Mandatory Bulletin MB No.: L13/109a, 

dated June 18, 2010. The actions 

described in this service information are 

intended to correct the unsafe condition 

identified in the MCAI. 

FAA’s Determination and Requirements 

of the AD 

This product has been approved by 

the aviation authority of another 

country, and is approved for operation 

in the United States. Pursuant to our 

bilateral agreement with this State of 

Design Authority, they have notified us 

of the unsafe condition described in the 

MCAI and service information 

referenced above. We are issuing this 

AD because we evaluated all 

information provided by the State of 

Design Authority and determined the 

unsafe condition exists and is likely to 

exist or develop on other products of the 

same type design. 

Differences Between This AD and the 

MCAI or Service Information 

We have reviewed the MCAI and 

related service information and, in 

general, agree with their substance. But 

we might have found it necessary to use 

different words from those in the MCAI 

to ensure the AD is clear for U.S. 

operators and is enforceable. In making 

these changes, we do not intend to differ 

substantively from the information 

provided in the MCAI and related 

service information. 

We might have also required different 

actions in this AD from those in the 

MCAI in order to follow FAA policies. 

Any such differences are described in a 

separate paragraph of the AD. These 

requirements take precedence over 

those copied from the MCAI. 

FAA’s Determination of the Effective 

Date 

An unsafe condition exists that 

requires the immediate adoption of this 

AD. The FAA has found that the risk to 

the flying public justifies waiving notice 

and comment prior to adoption of this 

rule because a fatal accident occurred in 

an L–13 Blanik glider. The main spar of 

the right wing of the accident glider 

failed near the root due to positive load. 

The right wing detached from the 

aircraft and the pilots lost control. The 

preliminary investigation has revealed 

that the fracture may have been due to 

fatigue. Therefore, we determined that 

notice and opportunity for public 

comment before issuing this AD are 

impracticable and that good cause exists 

for making this amendment effective in 

fewer than 30 days. 

Comments Invited 

This AD is a final rule that involves 

requirements affecting flight safety, and 

we did not precede it by notice and 

opportunity for public comment. We 

invite you to send any written relevant 

data, views, or arguments about this AD. 

Send your comments to an address 

listed under the ADDRESSES section. 

Include ‘‘Docket No. FAA–2010–0684; 

Directorate Identifier 2010–CE–031–AD’’ 

at the beginning of your comments. We 

specifically invite comments on the 

overall regulatory, economic, 

environmental, and energy aspects of 

this AD. We will consider all comments 

received by the closing date and may 

amend this AD because of those 

comments. 

We will post all comments we 

receive, without change, to http:// 

www.regulations.gov, including any 

personal information you provide. We 

will also post a report summarizing each 

substantive verbal contact we receive 

about this AD. 


jlentini on DSKJ8SOYB1PROD with RULES
Federal Register / Vol. 75, No. 133 / Tuesday, July 13, 2010 / Rules and Regulations 39797 

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 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); 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 AD and placed it in the AD docket. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, Incorporation by reference, 

Safety. 

Adoption of the Amendment 

■ Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA amends 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. 

§ 39.13 [Amended] 

■ 2. The FAA amends § 39.13 by adding 

the following new AD: 

2010–14–15 Aircraft Industries a.s. (Type 

Certificate G60EU Previously Held by 

LETECKE ́ ZA ́ VODY a.s. and LET 

Aeronautical Works): Amendment 39– 

16360; Docket No. FAA–2010–0684; 

Directorate Identifier 2010–CE–031–AD. 

Effective Date 

(a) This airworthiness directive (AD) 

becomes effective July 19, 2010. 

Affected ADs 

(b) None. 

Applicability 

(c) This AD applies to Models L–13 Blanik 

gliders, all serial numbers, certificated in any 

category. 

Subject 

(d) Air Transport Association of America 

(ATA) Code 57: Wings. 

Reason 

(e) The mandatory continuing 

airworthiness information (MCAI) states: 

A fatal accident occurred to a L–13 

BLANI ́K sailplane, in which the main spar of 

the right wing failed near the root due to 

positive load. The right wing detached from 

the aircraft and the pilots lost control of the 

sailplane. 

The preliminary investigation has revealed 

that the fracture may have been due to 

fatigue. 

The Emergency AD 2010–0119–E required 

immediate inspection of the main spar at the 

root of the wing to detect fatigue cracking 

and the accomplishment of the relevant 

corrective actions as necessary. In addition, 

this AD 2010–0119–E imposed operational 

limitations. This AD retains the requirements 

of AD 2010–0119–E, which is superseded, 

and extends the applicability to L–13 A 

BLANI ́K sailplanes. 

The requirements of this AD are 

considered as interim action to immediately 

address this unsafe condition. If, as a result 

of the on-going investigation, a terminating 

action is later identified, further mandatory 

actions might be considered. 

Actions and Compliance 

(f) Unless already done, do the following 

actions. 

(1) As of July 19, 2010, aerobatics 

maneuvers (i.e., roll, loop, stalled turn, 

immelmann turn, half roll, and inverted 

flight) are prohibited. Before further flight 

after July 19, 2010, insert a copy of this AD 

into the flight manual to comply with the 

requirements of this paragraph. The chapter 

‘‘Aerobatics’’ in ‘‘Pilot’s Notes for the L–13 

sailplane’’ (flight manual) is not valid. 

(2) Before further flight after July 19, 2010, 

inspect the wing critical areas following 

Aircraft Industries a.s. Mandatory Bulletin 

MB No.: L13/109a, dated June 18, 2010, 

except use a 10X magnifier. 

(3) If any cracks are found during the 

inspection required by paragraph (f)(2) of this 

AD, no further flights are permitted. 

(4) Within 10 days after the inspection 

required by paragraph (f)(2) of this AD, 

submit the following information requested 

by Aircraft Industries a.s. Mandatory Bulletin 

MB No.: L13/109a, dated June 18, 2010, for 

further assessment. Send information to the 

address listed in paragraph (i)(2) of this AD. 

(i) Appendix No. 1, Summary of L–13 

glider Log book record; and 

(ii) Paragraph H. RECORD IN GLIDER 

LOGBOOK AFTER BULLETIN EXECUTION. 

Note 1: The above limitation is an interim 

solution until a final action is identified, at 

which time the European Aviation Safety 

Agency (EASA) and the FAA may consider 

further AD action. 

FAA AD Differences 

Note 2: This AD differs from the MCAI 

and/or service information as follows. The 

service information requires a visual 

inspection with a 6X magnifier. We are 

requiring a 10X magnifier to detect cracks 

that could go undetected using only a 6X 

magnifier. 

Other FAA AD Provisions 

(g) The following provisions also apply to 

this AD: 

(1) Alternative Methods of Compliance 

(AMOCs): The Manager, Standards 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: Greg Davison, Aerospace Engineer, 

FAA, Small Airplane Directorate, 901 Locust, 

Room 301, Kansas City, Missouri 64106; 

telephone: (816) 329–4130; fax: (816) 329– 

4090. Before using any approved AMOC on 

any airplane to which the AMOC applies, 

notify your appropriate principal inspector 

(PI) in the FAA Flight Standards District 

Office (FSDO), or lacking a PI, your local 

FSDO. 

(2) Airworthy Product: For any 

requirement in this AD to obtain corrective 

actions from a manufacturer or other source, 

use these actions if they are FAA-approved. 

Corrective actions are considered FAAapproved if they are approved by the State 

of Design Authority (or their delegated 

agent). You are required to assure the product 

is airworthy before it is returned to service. 

(3) Reporting Requirements: For any 

reporting requirement in this AD, under the 

provisions of the Paperwork Reduction Act 

(44 U.S.C. 3501 et.seq.), the Office of 

Management and Budget (OMB) has 

approved the information collection 

requirements and has assigned OMB Control 

Number 2120–0056. 

Related Information 

(h) Refer to MCAI EASA Emergency AD 

No.: 2010–0122–E, dated June 23, 2010; and 

Aircraft Industries a.s. Mandatory Bulletin 

MB No.: L13/109a, dated June 18, 2010, for 

related information. 

Material Incorporated by Reference 

(i) You must use Aircraft Industries a.s. 

Mandatory Bulletin MB No.: L13/109a, dated 

June 18, 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 


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39798 Federal Register / Vol. 75, No. 133 / Tuesday, July 13, 2010 / Rules and Regulations 

this service information under 5 U.S.C. 

552(a) and 1 CFR part 51. 

(2) For service information identified in 

this AD, contact Aircraft Industries, a.s., Na 

Za ́honech 1177, 686 04 Kunovice, Czech 

Republic; phone: +420 572 817 660; fax: +420 

572 816 112; Internet: http://www.let.cz/; email: ots@let.cz. 

(3) You may review copies of the service 

information incorporated by reference for 

this AD at the FAA, Central Region, Office of 

the Regional Counsel, 901 Locust, Kansas 

City, Missouri 64106. For information on the 

availability of this material at the Central 

Region, call (816) 329–3768. 

(4) You may also review copies of the 

service information incorporated by reference 

for this AD 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. 

Issued in Kansas City, Missouri, on June 

28, 2010. 

James E. Jackson, 

Acting Manager, Small Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2010–16382 Filed 7–12–10; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2010–0382; Directorate 

Identifier 2009–NM–211–AD; Amendment 

39–16361; AD 2010–14–16] 

RIN 2120–AA64 

Airworthiness Directives; Bombardier, 

Inc. Model DHC–8–400, –401, and –402 

Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Final rule. 

SUMMARY: We are superseding an 

existing airworthiness directive (AD) for 

the products listed above. This AD 

results from mandatory continuing 

airworthiness information (MCAI) 

originated by an aviation authority of 

another country to identify and correct 

an unsafe condition on an aviation 

product. The MCAI describes the unsafe 

condition as: 

Several cases have been reported where a 

loss of fluid in the No.2 hydraulic system has 

caused the power transfer unit (PTU) to 

overspeed, resulting in pressure fluctuations 

and increased fluid flow within the No. 1 

hydraulic system. In one case, the hydraulic 

system control logic did not shut down the 

PTU and the overspeed condition persisted, 

resulting in the illumination of the No.1 HYD 

FLUID HOT caution light. 

* * * * * 

The unsafe condition is possible loss of 

both the No. 1 and No. 2 hydraulic 

systems, resulting in the potential loss 

of several functions essential for safe 

flight and landing of the airplane. We 

are issuing this AD to require actions to 

correct the unsafe condition on these 

products. 

DATES: This AD becomes effective 

August 17, 2010. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of August 17, 2010. 

The Director of the Federal Register 

approved the incorporation by reference 

of certain publications listed in this AD 

as of September 2, 2008 (73 FR 47818, 

August 15, 2008). 

The Director of the Federal Register 

approved the incorporation by reference 

of certain other publications listed in 

this AD as of July 10, 2007 (72 FR 

30968, June 5, 2007). 

ADDRESSES: You may examine the AD 

docket on the Internet at http:// 

www.regulations.gov or in person at the 

U.S. Department of Transportation, 

Docket Operations, M–30, West 

Building Ground Floor, Room W12–140, 

1200 New Jersey Avenue, SE., 

Washington, DC. 

FOR FURTHER INFORMATION CONTACT: 

Fabio Buttitta, Aerospace Engineer, 

Airframe and Mechanical Systems 

Branch, ANE–171, FAA, New York 

Aircraft Certification Office, 1600 

Stewart Avenue, Suite 410, Westbury, 

New York 11590; telephone (516) 228– 

7303; fax (516) 794–5531. 

SUPPLEMENTARY INFORMATION: 

Discussion 

We issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 to include an AD that would 

apply to the specified products. That 

NPRM was published in the Federal 

Register on April 21, 2010 (75 FR 

20787), and proposed to supersede AD 

2008–17–06, Amendment 39–15644 (73 

FR 47818, August 15, 2008). That NPRM 

proposed to correct an unsafe condition 

for the specified products. The MCAI 

states: 

Since we issued AD 2008–17–06, a 

modification of the power transfer unit 

(PTU) control logic, including the 

provision of automatic PTU shutdown 

in the event of loss of fluid in the No. 

2 hydraulic system, has been developed. 

The modification addresses the 

identified unsafe condition. In addition, 

the applicability has been revised to 

remove airplanes having serial number 

4185 and subsequent, since an 

equivalent modification has been 

installed in production on these 

airplanes. Transport Canada Civil 

Aviation (TCCA), which is the aviation 

authority for Canada, has issued 

Canadian Airworthiness Directive CF– 

2006–08R1, dated August 31, 2009 

(referred to after this as ‘‘the MCAI’’), to 

correct an unsafe condition for the 

specified products. The MCAI states: 

Several cases have been reported where a 

loss of fluid in the No.2 hydraulic system has 

caused the power transfer unit (PTU) to 

overspeed, resulting in pressure fluctuations 

and increased fluid flow within the No. 1 

hydraulic system. In one case, the hydraulic 

system control logic did not shut down the 

PTU and the overspeed condition persisted, 

resulting in the illumination of the No. 1 

HYD FLUID HOT caution light. 

As an interim action to avoid possible loss 

of both the No. 1 and No. 2 hydraulic 

systems, the Airplane Flight Manual (AFM) 

has been revised to include pulling the HYD 

PWR XFER circuit breaker in the event of the 

loss of all hydraulic fluid in the No. 2 

hydraulic system. 

Insertion of the resultant Temporary 

Amendment (TA) No. 13 into the AFM was 

mandated in the original issue of this 

[Canadian] directive. This instruction * * * 

remains in effect until * * * this [revised] 

directive is accomplished. 

Revision 1 of this directive * * * 

mandates modification of the PTU control 

logic, including the provision of automatic 

PTU shutdown in the event of loss of fluid 

in the No. 2 hydraulic system. In addition, 

the applicability of the [Canadian] directive 

has been revised to remove aircraft Serial 

Number (SN) 4185 and subsequent, since an 

equivalent modification has been installed in 

production on these aircraft. 

The unsafe condition is possible loss of 

both the No. 1 and No. 2 hydraulic 

systems, resulting in the potential loss 

of several functions essential for safe 

flight and landing of the airplane. You 

may obtain further information by 

examining the MCAI in the AD docket. 

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 available data and 

determined that air safety and the 

public interest require adopting the AD 

as proposed. 

Differences Between This AD and the 

MCAI or Service Information 

We have reviewed the MCAI and 

related service information and, in 

general, agree with their substance. But 

we might have found it necessary to use 


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