Federal Register / Vol. 70, No. 216 / Wednesday, November 9, 2005 / Proposed Rules 67949 

Costs of Compliance 

The following table provides the 

estimated costs for U.S. operators to 

comply with this proposed AD. 

ESTIMATED COSTS

Action Work hours Average labor 

rate per hour Parts Cost per airplane 

Number of 

U.S.-registered 

airplanes 

Fleet cost 

Rivet installation ................................. 1 $65 Operator-supplied ...... $65 108 $7,020 

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 

proposed AD would not have federalism 

implications under Executive Order 

13132. This proposed AD would 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 the proposed regulation: 

1. Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866; 

2. Is not a ‘‘significant rule’’ under the 

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 proposed AD and placed it in the 

AD docket. See the ADDRESSES section 

for a location to examine the regulatory 

evaluation. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, Safety. 

The Proposed Amendment 

Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA proposes to amend 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 Federal Aviation 

Administration (FAA) amends § 39.13 

by adding the following new 

airworthiness directive (AD): 

Empresa Brasileira de Aeronautica S.A. 

(EMBRAER): Docket No. FAA–2005–

22871; Directorate Identifier 2005–NM–

191–AD. 

Comments Due Date 

(a) The FAA must receive comments on 

this AD action by December 9, 2005. 

Affected ADs 

(b) None. 

Applicability 

(c) This AD applies to EMBRAER Model 

EMB–120, –120ER, –120FC, –120QC, and 

–120RT airplanes, certificated in any 

category; as identified in EMBRAER Service 

Bulletin 120–53–0080, dated November 30, 

2004. 

Unsafe Condition 

(d) This AD results from a report indicating 

that, during production, a pinhole was left 

open at the upper frame of the auxiliary 

power unit (APU) firewall. We are issuing 

this AD to ensure that the APU compartment 

is isolated from the rest of the airplane in the 

event of an APU fire. 

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. 

Rivet Installation 

(f) Within 4,000 flight hours or 24 months, 

whichever occurs first after the effective date 

of this AD: Install a rivet and washer in the 

hole of the upper frame of the APU firewall, 

in accordance with EMBRAER Service 

Bulletin 120–53–0080, dated November 30, 

2004. 

Alternative Methods of Compliance 

(AMOCs) 

(g)(1) The Manager, International Branch, 

ANM–116, Transport Airplane Directorate, 

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. 

Related Information 

(h) Brazilian airworthiness directive 2005–

08–03, dated September 5, 2005, also 

addresses the subject of this AD. 

Issued in Renton, Washington, on October 

26, 2005. 

Kalene C. Yanamura, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. 05–22304 Filed 11–8–05; 8:45 am] 

BILLING CODE 4910–13–U 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2005–22875; Directorate 

Identifier 2005–NM–179–AD] 

RIN 2120–AA64 

Airworthiness Directives; Short 

Brothers Model SD3–60 SHERPA, 

SD3–SHERPA, and SD3–60 Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to 

supersede an existing airworthiness 

67950 Federal Register / Vol. 70, No. 216 / Wednesday, November 9, 2005 / Proposed Rules 

directive (AD) that applies to all Short 

Brothers Model SD3–60 and SD3–

SHERPA airplanes. The existing AD 

currently requires an inspection of the 

fork end of the rear pintle pin on each 

main landing gear (MLG) to verify that 

sealant is properly applied and is 

undamaged, and related investigative/ 

corrective actions if necessary. This 

proposed AD would add an inspection 

for correctly applied sealant on the MLG 

rear pintle pin assemblies, and related 

investigative/corrective actions if 

necessary. This proposed AD would 

also expand the applicability of the 

existing AD. This proposed AD results 

from a new report of a cracked pintle 

pin fork end. We are proposing this AD 

to prevent stress-corrosion cracking and 

subsequent failure of the MLG. 

DATES: We must receive comments on 

this proposed AD by December 9, 2005. 

ADDRESSES: Use one of the following 

addresses to submit comments on this 

proposed AD. 

• DOT Docket Web site: Go to 

http://dms.dot.gov and follow the 

instructions for sending your comments 

electronically. 

• Government-wide rulemaking Web 

site: Go to http://www.regulations.gov 

and follow the instructions for sending 

your comments electronically. 

• Mail: Docket Management Facility; 

U.S. Department of Transportation, 400 

Seventh Street SW., Nassif Building, 

room PL–401, Washington, DC 20590. 

• Fax: (202) 493–2251. 

• Hand Delivery: Room PL–401 on 

the plaza level of the Nassif Building, 

400 Seventh Street SW., Washington, 

DC, between 9 a.m. and 5 p.m., Monday 

through Friday, except Federal holidays. 

Contact Short Brothers, Airworthiness 

& Engineering Quality, P.O. Box 241, 

Airport Road, Belfast BT3 9DZ, 

Northern Ireland, for service 

information identified in this proposed 

AD. 

FOR FURTHER INFORMATION CONTACT: Dan 

Rodina, Aerospace Engineer, 

International Branch, ANM–116, FAA, 

Transport Airplane Directorate, 1601 

Lind Avenue, SW., Renton, Washington 

98055–4056; telephone (425) 227–2125; 

fax (425) 227–1149. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

We invite you to submit any relevant 

written data, views, or arguments 

regarding this proposed AD. Send your 

comments to an address listed in the 

ADDRESSES section. Include the docket 

number ‘‘Docket No. FAA–2005–22875; 

Directorate Identifier 2005–NM–179–

AD’’ at the beginning of your comments. 

We specifically invite comments on the 

overall regulatory, economic, 

environmental, and energy aspects of 

the proposed AD. We will consider all 

comments received by the closing date 

and may amend the proposed AD in 

light of those comments. 

We will post all comments we 

receive, without change, to http:// 

dms.dot.gov, including any personal 

information you provide. We will also 

post a report summarizing each 

substantive verbal contact with FAA 

personnel concerning this proposed AD. 

Using the search function of that web 

site, anyone can find and read the 

comments in any of our dockets, 

including the name of the individual 

who sent the comment (or signed the 

comment on behalf of an association, 

business, labor union, etc.). You may 

review the DOT’s complete Privacy Act 

Statement in the Federal Register 

published on April 11, 2000 (65 FR 

19477–78), or you may visit http:// 

dms.dot.gov. 

Examining the Docket 

You may examine the AD docket on 

the Internet at http://dms.dot.gov, or in 

person at the Docket Management 

Facility office between 9 a.m. and 5 

p.m., Monday through Friday, except 

Federal holidays. The Docket 

Management Facility office (telephone 

(800) 647–5227) is located on the plaza 

level of the Nassif Building at the DOT 

street address stated in the ADDRESSES

section. Comments will be available in 

the AD docket shortly after the Docket 

Management System receives them. 

Discussion 

On January 25, 1993, we issued AD 

93–02–03, amendment 39–8485 (58 FR 

7983, February 11, 1993), for all Short 

Brothers Model SD3–60 and SD3–

SHERPA airplanes. That AD requires an 

inspection of the fork end of the rear 

pintle pin on each main landing gear 

(MLG) to verify that sealant is properly 

applied and is undamaged; removal of 

the bushings and an inspection to detect 

faults of the bores in the fork end, if 

necessary; and repair of the fork end of 

the pintle pin, if necessary. That AD 

resulted from a report of a cracked fork 

end of the MLG rear pintle pin. We 

issued that AD to prevent stresscorrosion cracking and subsequent 

failure of the MLG. 

Actions Since Existing AD Was Issued 

Since we issued AD 93–02–03, we 

have learned about another incident of 

a cracked pintle pin fork end on a 

Model SD3 airplane. 

Relevant Service Information 

Shorts has issued Service Bulletins 

SD360 Sherpa–32–4 (for Model SD3–60 

SHERPA airplanes), SD3 Sherpa–32–5 

(for Model SD3–SHERPA airplanes), 

and SD360–32–37 (for Model SD3–60 

airplanes), all dated July 2004. The 

service bulletins describe procedures for 

an inspection to determine whether 

sealant has been properly applied on the 

MLG rear pintle pin assemblies, and 

related investigative/corrective actions 

for missing or damaged sealant. 

Accomplishing the actions specified in 

the service information is intended to 

adequately address the unsafe 

condition. The Civil Aviation Authority 

(CAA), which is the airworthiness 

authority for the United Kingdom, 

mandated the service information and 

issued British airworthiness directive 

G–2004–0022, dated August 25, 2004, to 

ensure the continued airworthiness of 

these airplanes in the United Kingdom. 

The service bulletins refer to Messier 

Dowty Service Bulletin 32–70SD, 

Revision 1, dated July 3, 1995, as an 

additional source of service information 

for the inspection and related 

investigative/corrective actions. 

FAA’s Determination and Requirements 

of the Proposed AD 

These airplane models are 

manufactured in the United Kingdom 

and are type certificated for operation in 

the United States under the provisions 

of section 21.29 of the Federal Aviation 

Regulations (14 CFR 21.29) and the 

applicable bilateral airworthiness 

agreement. Pursuant to this bilateral 

airworthiness agreement, the CAA has 

kept the FAA informed of the situation 

described above. We have examined the 

CAA’s findings, evaluated all pertinent 

information, and determined that AD 

action is necessary for airplanes of this 

type design that are certificated for 

operation in the United States. 

This proposed AD would supersede 

AD 93–02–03 and would retain the 

requirements of the existing AD. This 

proposed AD would also expand the 

applicability for the actions specified in 

service information described 

previously, except as discussed below. 

Difference Between the Proposed AD 

and Service Information 

The service information specifies to 

contact the manufacturer for 

instructions on how to repair certain 

conditions, but this proposed AD would 

require repairing those conditions using 

a method that we or the CAA (or its 

delegated agent) approve. In light of the 

type of repair that would be required to 

address the unsafe condition, and 

Federal Register / Vol. 70, No. 216 / Wednesday, November 9, 2005 / Proposed Rules 67951 

consistent with existing bilateral 

airworthiness agreements, we have 

determined that, for this proposed AD, 

a repair we or the CAA approve would 

be acceptable for compliance with this 

proposed AD. 

Clarification of Inspection Terminology 

In this proposed AD, the inspection 

specified in the service bulletins is 

referred to as a ‘‘general visual 

inspection.’’ Note 1 in this proposed AD 

defines this type of inspection. 

Costs of Compliance 

The following table provides the 

estimated costs for U.S. operators to 

comply with this proposed AD. 

ESTIMATED COSTS

Action Work hours 

Average labor 

rate 

per hour 

Parts Cost per airplane 

Number of 

U.S.-registered 

airplanes 

Fleet cost 

Inspection (required by AD 93–02–03) .... 1 $65 None $65 42 $2,730 

Inspection (new proposed action) ............ 1 65 None 65 42 2,730 

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 

proposed AD would not have federalism 

implications under Executive Order 

13132. This proposed AD would 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 the proposed regulation: 

1. Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866; 

2. Is not a ‘‘significant rule’’ under the 

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 proposed AD and placed it in the 

AD docket. See the ADDRESSES section 

for a location to examine the regulatory 

evaluation. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, Safety. 

The Proposed Amendment 

Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA proposes to amend 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 Federal Aviation 

Administration (FAA) amends § 39.13 

by removing amendment 39–8485 (58 

FR 7983, February 11, 1993) and adding 

the following new airworthiness 

directive (AD): 

Short Brothers PLC: Docket No. FAA–2005–

22875; Directorate Identifier 2005–NM–

179–AD. 

Comments Due Date 

(a) The FAA must receive comments on 

this AD action by December 9, 2005. 

Affected ADs 

(b) This AD supersedes AD 93–02–03. 

Applicability 

(c) This AD applies to all Shorts Model 

SD3–60 SHERPA, SD3–SHERPA, and SD3–

60 airplanes, certificated in any category. 

Unsafe Condition 

(d) This AD results from a new report of 

a cracked pintle pin fork end. We are issuing 

this AD to prevent stress-corrosion cracking 

and subsequent failure of the main landing 

gear (MLG). 

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. 

Restatement of Requirements of AD 93–02–

03 

Inspection 

(f) For Model SD3–60 and SD3–SHERPA 

airplanes: Within 300 hours’ time-in-service 

or 30 days after March 18, 1993 (the effective 

date of AD 93–02–03), whichever occurs first, 

perform a visual inspection of the fork end 

of the rear pintle pin on each MLG to verify 

that an undamaged fillet of sealant is 

properly applied around the flanges of the 

bronze bushings, in accordance with Shorts 

SD3–60 Service Bulletin SD360–32–33, dated 

August 7, 1992. 

(1) If an undamaged fillet of properly 

applied sealant is found: No further action is 

required by this AD. 

(2) If no fillet of sealant is found at the joint 

line, or if a damaged fillet of sealant is found: 

Prior to the accumulation of 1,200 hours’

time-in-service or 120 days after 

accomplishing the inspection required by 

paragraph (f) of this AD, whichever occurs 

first, remove the bushings and perform a 

magnetic non-destructive testing (NDT) 

inspection to detect faults of the bores in the 

fork end, in accordance with the service 

bulletin. If faults are found as a result of the 

NDT inspection, prior to further flight, repair 

the fork end of the rear pintle pin in a 

manner approved by the Manager, 

International Branch, ANM–116, Transport 

Airplane Directorate, FAA. 

New Requirements of This AD 

Inspection 

(g) For all airplanes: Within 3 months after 

the effective date of this AD, do a general 

visual inspection of the MLG rear pintle pin 

assemblies for correctly applied sealant, in 

accordance with Shorts Service Bulletin 

SD360–32–37, SD3 SHERPA–32–5, or SD360 

SHERPA 32–4, all dated July 2004, as 

applicable. 

(1) If the sealant is applied correctly: This 

AD requires no further work. 

(2) If the sealant is applied incorrectly: 

Within 12 months after the effective date of 

this AD, do a magnetic flaw detection 

inspection to detect cracks of the rear pintle 

pin fork ends, in accordance with the service 

bulletin. If any cracked pintle pin fork end 

is found: Replace it before further flight with 

a serviceable part that has been inspected in 

accordance with the requirements of this AD. 

Note 1: For the purposes of this AD, a 

general visual inspection is: ‘‘A visual 

67952 Federal Register / Vol. 70, No. 216 / Wednesday, November 9, 2005 / Proposed Rules 

examination of an interior or exterior area, 

installation, or assembly to detect obvious 

damage, failure, or irregularity. This level of 

inspection is made from within touching 

distance unless otherwise specified. A mirror 

may be necessary to ensure visual access to 

all surfaces in the inspection area. This level 

of inspection is made under normally 

available lighting conditions such as 

daylight, hangar lighting, flashlight, or 

droplight and may require removal or 

opening of access panels or doors. Stands, 

ladders, or platforms may be required to gain 

proximity to the area being checked.’’

Note 2: The service bulletins identified in 

paragraph (g) of this AD refer to Messier 

Dowty Service Bulletin 32–70SD, Revision 1, 

dated July 3, 1995, as an additional source of 

service information for the inspection and 

corrective actions. 

(h) If any crack is detected during any 

inspection required by this AD and the 

service information specifies to contact the 

manufacturer for repair instructions: Before 

further flight, repair using a method 

approved by either the Manager, 

International Branch, ANM–116, Transport 

Airplane Directorate, FAA; or the Civil 

Aviation Authority (CAA) (or its delegated 

agent). 

Alternative Methods of Compliance (AMOCs) 

(i)(1) The Manager, International Branch, 

ANM–116, Transport Airplane Directorate, 

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. 

Related Information 

(j) British airworthiness directive G–2004–

0022, dated August 25, 2004, also addresses 

the subject of this AD. 

Issued in Renton, Washington, on October 

28, 2005. 

Kalene C. Yanamura, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. 05–22305 Filed 11–8–05; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2005–22874; Directorate 

Identifier 2005–NM–173–AD] 

RIN 2120–AA64 

Airworthiness Directives; Boeing 

Model 777–200 and –300 Series 

Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for 

certain Boeing Model 777–200 and –300 

series airplanes. This proposed AD 

would require inspecting the lower web 

of the aft fairing of engine struts for any 

discoloration and doing any related 

investigative and corrective action if 

necessary; inspecting the heat shield 

castings for any damage and doing any 

corrective action if necessary; installing 

gap cover strips; and replacing 

insulation blankets with new insulation 

blankets. This proposed AD results from 

a report that several discolored fairing 

lower webs and some damaged/ 

deteriorated insulation blankets were 

found in the aft fairings of engine struts. 

We are proposing this AD to prevent 

cracking of lower webs of the aft 

fairings, which could result in 

flammable hydraulic fluid leaking onto 

or near an ignition source, and possibly 

result in an uncontrollable fire in the 

engine strut area. 

DATES: We must receive comments on 

this proposed AD by December 27, 

2005. 

ADDRESSES: Use one of the following 

addresses to submit comments on this 

proposed AD. 

• DOT Docket Web site: Go to 

http://dms.dot.gov and follow the 

instructions for sending your comments 

electronically. 

• Government-wide rulemaking Web 

site: Go to http://www.regulations.gov 

and follow the instructions for sending 

your comments electronically. 

• Mail: Docket Management Facility, 

U.S. Department of Transportation, 400 

Seventh Street, SW., Nassif Building, 

room PL–401, Washington, DC 20590. 

• Fax: (202) 493–2251. 

• Hand Delivery: Room PL–401 on 

the plaza level of the Nassif Building, 

400 Seventh Street, SW., Washington, 

DC, between 9 a.m. and 5 p.m., Monday 

through Friday, except Federal holidays. 

Contact Boeing Commercial 

Airplanes, P.O. Box 3707, Seattle, 

Washington 98124–2207, for the service 

information identified in this proposed 

AD. 

FOR FURTHER INFORMATION CONTACT: John 

Vann, Aerospace Engineer, Propulsion 

Branch, ANM–140S, FAA, Seattle 

Aircraft Certification Office, 1601 Lind 

Avenue, SW., Renton, Washington 

98055–4056; telephone (425) 917–6513; 

fax (425) 917–6590. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

We invite you to submit any relevant 

written data, views, or arguments 

regarding this proposed AD. Send your 

comments to an address listed in the 

ADDRESSES section. Include the docket 

number ‘‘FAA–2005–22874; Directorate 

Identifier 2005–NM–173–AD’’ at the 

beginning of your comments. We 

specifically invite comments on the 

overall regulatory, economic, 

environmental, and energy aspects of 

the proposed AD. We will consider all 

comments received by the closing date 

and may amend the proposed AD in 

light of those comments. 

We will post all comments we 

receive, without change, to http:// 

dms.dot.gov, including any personal 

information you provide. We will also 

post a report summarizing each 

substantive verbal contact with FAA 

personnel concerning this proposed AD. 

Using the search function of that web 

site, anyone can find and read the 

comments in any of our dockets, 

including the name of the individual 

who sent the comment (or signed the 

comment on behalf of an association, 

business, labor union, etc.). You may 

review DOT’s complete Privacy Act 

Statement in the Federal Register 

published on April 11, 2000 (65 FR 

19477–78), or you may visit http:// 

dms.dot.gov. 

Examining the Docket 

You may examine the AD docket on 

the Internet at http://dms.dot.gov, or in 

person at the Docket Management 

Facility office between 9 a.m. and 5 

p.m., Monday through Friday, except 

Federal holidays. The Docket 

Management Facility office (telephone 

(800) 647–5227) is located on the plaza 

level of the Nassif Building at the DOT 

street address stated in the ADDRESSES

section. Comments will be available in 

the AD docket shortly after the Docket 

Management System receives them. 

Discussion 

We have received a report indicating 

that damaged/deteriorated thermal 

insulation blankets and discolored 

fairing lower webs were found in the aft 

fairings of engine struts on several 

Model 777–200 and –300 series 

airplanes. Gaps in the segmented heat 

shield in the strut aft fairings allow 

engine primary/main exhaust to enter 

the heat shield cavity in the strut aft 

fairing. The temperature of the exhaust 

that leaks into the heat shield cavity 

exceeds the insulation blankets’

maximum design tolerance. Since the 

insulation blankets provide thermal 

protection for the aluminum fairing 

lower web, degradation of an insulation 

blanket allows thermal distress of the 

lower web and eventually, cracking of 

the lower web. A cracked lower web is