Federal Register / Vol. 74, No. 87 / Thursday, May 7, 2009 / Rules and Regulations 21251 

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: 

2009–09–08 Boeing: Amendment 39–15894. 

Docket No. FAA–2008–1239; Directorate 

Identifier 2008–NM–131–AD. 

Effective Date 

(a) This airworthiness directive (AD) is 

effective June 11, 2009. 

Affected ADs 

(b) None. 

Applicability 

(c) This AD applies to Boeing Model 747– 

100, 747–100B, 747–100B SUD, 747–200B, 

747–200C, 747–200F, 747–300, 747–400, 

747–400D, 747–400F, 747SR, and 747SP 

series airplanes, certificated in any category; 

as identified in Boeing Alert Service Bulletin 

747–53A2651, dated June 12, 2008. 

Unsafe Condition 

(d) This AD results from reports of cracks 

in the radius detail of the upper lobe 

doublers. We are issuing this AD to detect 

and correct cracks in the upper lobe 

doublers. Such cracks could result in 

significant degradation of the fuselage 

structure and reduce its ability to carry flight 

loads from the vertical stabilizer, which 

could adversely affect the controllability of 

the airplane. 

Compliance 

(e) Comply with this AD within the 

compliance times specified, unless already 

done. 

Inspection(s) and Corrective Action 

(f) At the applicable times specified in 

paragraph 1.E., ‘‘Compliance,’’ of Boeing 

Alert Service Bulletin 747–53A2651, dated 

June 12, 2008, except as required by 

paragraph (i) of this AD, do an external 

surface high frequency eddy current 

inspection to detect cracks in the radius 

detail of the upper lobe doubler on both sides 

of the airplane, and the applicable corrective 

action, by accomplishing all the applicable 

actions specified in the Accomplishment 

Instructions of the service bulletin, except as 

required by paragraphs (g) and (h) of this AD. 

The applicable corrective action must be 

done before further flight. As applicable, 

repeat the inspection thereafter at the 

applicable times specified in paragraph 1.E., 

‘‘Compliance,’’ of Boeing Alert Service 

Bulletin 747–53A2651, dated June 12, 2008. 

(g) Where Boeing Alert Service Bulletin 

747–53A2651, dated June 12, 2008, 

paragraph 3.B., Work Instructions, PART 3, 

Step 1, specifies a sealant application ‘‘from 

STA 2520 to STA 2521,’’ this AD requires a 

sealant application ‘‘from STA 2491 to STA 

2521’’ on both sides of the airplane. 

(h) Where Boeing Alert Service Bulletin 

747–53A2651, dated June 12, 2008, specifies 

to contact Boeing for repair instructions 

instead of repairing or replacing any cracked 

upper lobe doubler in accordance with the 

service bulletin, this AD requires, before 

further flight, repairing any cracked upper 

lobe doubler using a method approved in 

accordance with the procedures specified in 

paragraph (j) of this AD. 

(i) Where Boeing Alert Service Bulletin 

747–53A2651, dated June 12, 2008, specifies 

a compliance time after the date on the 

service bulletin, this AD requires compliance 

within the specified compliance time after 

the effective date of this AD. 

Alternative Methods of Compliance 

(AMOCs) 

(j)(1) The Manager, Seattle Aircraft 

Certification Office (ACO), 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: Ivan 

Li, Aerospace Engineer, Airframe Branch, 

ANM–120S, FAA, Seattle ACO, 1601 Lind 

Avenue, SW., Renton, Washington 98057– 

3356; telephone (425) 917–6437; fax (425) 

917–6590. 

(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. 

(3) An AMOC that provides an acceptable 

level of safety may be used for any repair 

required by this AD, if it is approved by an 

Authorized Representative for the Boeing 

Commercial Airplanes Delegation Option 

Authorization Organization who has been 

authorized by the Manager, Seattle ACO, to 

make those findings. For a repair method to 

be approved, the repair must meet the 

certification basis of the airplane, and the 

approval must specifically refer to this AD. 

Material Incorporated by Reference 

(k) You must use Boeing Alert Service 

Bulletin 747–53A2651, dated June 12, 2008, 

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, Attention: Data & Services 

Management, P.O. Box 3707, MC 2H–65, 

Seattle, Washington 98124–2207; telephone 

206–544–5000, extension 1; fax 206–766– 

5680; e-mail me.boecom@boeing.com; 

Internet https://www.myboeingfleet.com. 

(3) 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 or 425–227–1152. 

(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 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, on April 22, 

2009. 

Stephen P. Boyd, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. E9–9925 Filed 5–6–09; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2008–1070; Directorate 

Identifier 2008–NM–087–AD; Amendment 

39–15893; AD 2009–09–07] 

RIN 2120–AA64 

Airworthiness Directives; Boeing 

Model 737–100, –200, –200C, –300, 

–400, and –500 Series Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for all 

Boeing Model 737–100, –200, –200C, 

–300, –400, and –500 series airplanes. 

For all airplanes, this AD requires 

repetitive overhaul of the retract 

actuator beam of the main landing gear 

(MLG). For certain airplanes, this AD 

requires repetitive inspections for 

damage of the retract actuator beam, and 

related investigative and corrective 

actions if necessary. This AD results 

from reports of broken retract actuator 

beams of the MLG and the subsequent 

failure of the MLG to fully retract. We 

are issuing this AD to detect and correct 

broken retract actuator beams of the 

MLG, which could cause damage to the 

beam arm, hydraulic tubing, and flight 

control cables. Damage to the flight 

control cables could result in loss of 

control of the airplane. 

DATES: This AD is effective June 11, 

2009. 

21252 Federal Register / Vol. 74, No. 87 / Thursday, May 7, 2009 / Rules and Regulations 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in the AD 

as of June 11, 2009. 

ADDRESSES: For service information 

identified in this AD, contact Boeing 

Commercial Airplanes, P.O. Box 3707, 

Seattle, Washington 98124–2207; 

telephone 206–544–9990; fax 206–766– 

5682; e-mail DDCS@boeing.com; 

Internet https:// 

www.myboeingfleet.com. 

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 address for the 

Docket Office (telephone 800–647–5527) 

is the Document Management Facility, 

U.S. Department of Transportation, 

Docket Operations, M–30, West 

Building Ground Floor, Room W12–140, 

1200 New Jersey Avenue, SE., 

Washington, DC 20590. 

FOR FURTHER INFORMATION CONTACT: 

Nancy Marsh, Aerospace Engineer, 

Airframe Branch, ANM–120S, FAA, 

Seattle Aircraft Certification Office, 

1601 Lind Avenue, SW., Renton, 

Washington 98057–3356; telephone 

(425) 917–6440; fax (425) 917–6590. 

SUPPLEMENTARY INFORMATION: 

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 all 

Boeing Model 737–100, –200, –200C, 

–300, –400, and –500 series airplanes. 

That NPRM was published in the 

Federal Register on October 8, 2008 (73 

FR 58906). For all airplanes, that NPRM 

proposed to require repetitive overhaul 

of the retract actuator beam of the main 

landing gear (MLG). For certain 

airplanes, that NPRM proposed to 

require repetitive inspections for 

damage of the retract actuator beam, and 

related investigative and corrective 

actions if necessary. 

Comments 

We gave the public the opportunity to 

participate in developing this AD. We 

considered the comments received from 

the commenters. 

Support for the NPRM 

Boeing concurs with the contents of 

the NPRM. 

Request To Change Overhaul 

Requirements 

Continental Airlines (CAL) asks that 

we not mandate overhaul of the retract 

actuator beam using the instructions 

specified in the Accomplishment 

Instructions of Boeing Service Bulletin 

737–32A1355, Revision 2, dated March 

5, 2008. CAL states that the reason for 

release of Boeing Service Bulletin 737– 

32A1355, Revision 2, is Boeing’s 

concern regarding shop process 

deficiencies at some repair facilities 

where correct overhaul procedures were 

not followed. CAL finds this reasoning 

detrimental to all operators that follow 

correct overhaul procedures at their 

repair facilities. 

CAL landing gear components, 

including the retract actuator beams of 

the left and right main landing gear, are 

time controlled per the Boeing 737–300/ 

–500 Maintenance Program and are 

scheduled to be overhauled at 10-year 

intervals at an FAA-approved landing 

gear overhaul facility. CAL also makes 

the following recommendations 

regarding Boeing Service Bulletin 737– 

32A1355, Revision 2: 

• The stripping of all chrome and 

nickel plating specified in Step 4 of 

Figure 2 should be included as an 

option, as in the Boeing 737 Component 

Maintenance Manual (CMM), Section 

32–00–05. 

• The nital etch inspection of 

machined surfaces specified only in 

Step 9 of Figure 2 should not be limited 

to machined surfaces. 

• The stress relieving of the part 

specified in Step 10 of Figure 2 should 

be an optional step, as specified in 

Boeing 737 CMM, Section 32–00–05. 

• The shot peening of the entire part 

specified in Step 12 of Figure 2 should 

be limited to the machined areas of the 

part since the geometry of the actuator 

beam does not allow for effective shot 

peening of the entire area. 

• A caution note for arc burns 

associated with grounding (similar to 

Step 14) should be included in Step 13 

of Figure 2. 

We disagree that using the 

instructions specified in the 

Accomplishment Instructions of Boeing 

Service Bulletin 737–32A1355, Revision 

2, dated March 5, 2008, to perform the 

overhaul of the retract actuator beam 

should not be mandated. Revision 2 of 

Boeing Service Bulletin 737–32A1355 

references improved overhaul 

procedures, and those procedures are 

required by this AD. However, 

according to the provisions of paragraph 

(i) of this AD, we may approve a request 

for using different overhaul procedures 

if the request includes data that prove 

that those procedures would provide an 

acceptable level of safety. We have not 

changed the AD in this regard. 

We acknowledge the request for 

changes to Boeing Service Bulletin 737– 

32A1355, Revision 2. At the present 

time, Boeing has not issued a revised 

service bulletin with the changes. 

However, if Boeing Service Bulletin 

737–32A1355, Revision 2, is revised 

after issuance of this AD, we might 

consider approving the revised service 

bulletin as an alternative method of 

compliance (AMOC) with the 

requirements of this AD. We have not 

changed the AD in this regard. 

Conclusion 

We reviewed the relevant data, 

considered the comments received, and 

determined that air safety and the 

public interest require adopting the AD 

as proposed. 

Costs of Compliance 

We estimate that this AD affects 652 

airplanes of U.S. registry. The following 

table provides the estimated costs for 

U.S. operators to comply with this AD. 

ESTIMATED COSTS

Action/airplane group Work hours Average labor 

rate per hour Parts cost Cost per product 

Number of 

U.S.-registered 

airplanes 

Fleet cost 

Overhaul for Group 1; Configurations 1, 2, and 3.64 $80 None ........... $5,120, per overhaul cycle .. 652 $3,338,240 

Inspection for Group 1, Configuration 3.1 80 None ........... $80, per inspection cycle ..... 525 42,000 

Federal Register / Vol. 74, No. 87 / Thursday, May 7, 2009 / Rules and Regulations 21253 

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. 

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: 

2009–09–07 Boeing: Amendment 39–15893. 

Docket No. FAA–2008–1070; Directorate 

Identifier 2008–NM–087–AD. 

Effective Date 

(a) This airworthiness directive (AD) is 

effective June 11, 2009. 

Affected ADs 

(b) None. 

Applicability 

(c) This AD applies to all Boeing Model 

737–100, –200, –200C, –300, –400, and –500 

series airplanes, certificated in any category. 

Unsafe Condition 

(d) This AD results from reports of broken 

retract actuator beams of the main landing 

gear (MLG) and the subsequent failure of the 

MLG to fully retract. We are issuing this AD 

to detect and correct broken retract actuator 

beams of the MLG, which could result in 

damage to the beam arm, hydraulic tubing, 

and flight control cables. Damage to the flight 

control cables could result in loss of control 

of the airplane. 

Compliance 

(e) Comply with this AD within the 

compliance times specified, unless already 

done. 

Inspection and Related Investigative and 

Corrective Actions/Overhaul 

(f) Except as provided by paragraphs (g) 

and (h) of this AD: At the applicable times 

specified in paragraph 1.E. of Boeing Service 

Bulletin 737–32A1355, Revision 2, dated 

March 5, 2008, inspect for damage of the 

retract actuator beam of the MLG and 

overhaul the retract actuator beam, as 

applicable, by doing all the applicable 

actions specified in the Accomplishment 

Instructions of Boeing Service Bulletin 737– 

32A1355, Revision 2, dated March 5, 2008. 

Do all applicable related investigative and 

corrective actions before further flight. 

Repeat the applicable inspection or overhaul 

thereafter at the applicable time specified in 

paragraph 1.E. of Boeing Service Bulletin 

737–32A1355, Revision 2, dated March 5, 

2008. 

Exceptions to Service Information 

(g) Where Boeing Service Bulletin 737– 

32A1355, Revision 2, dated March 5, 2008, 

specifies a compliance time after ‘‘* * * the 

date on this service bulletin,’’ this AD 

requires compliance within the specified 

compliance time after the effective date of 

this AD. 

(h) Boeing Service Bulletin 737–32A1355, 

Revision 2, dated March 5, 2008, specifies 

that the actions are for airplanes with new 

MLG retract actuator beams that have not 

been overhauled having part number (P/N) 

65–46108–15 and subsequent dash numbers; 

and new or overhauled MLG retract actuator 

beams having P/N 65–46108–14 and previous 

dash numbers. However, this AD is not 

limited to new or overhauled beams. This AD 

requires that the actions required by 

paragraph (f) of this AD be done on airplanes 

with any MLG retract actuator beam having 

those P/Ns. 

Alternative Methods of Compliance 

(AMOCs) 

(i)(1) The Manager, Seattle Aircraft 

Certification Office (ACO), 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: 

Nancy Marsh, Aerospace Engineer, Airframe 

Branch, ANM–120S, FAA, Seattle Aircraft 

Certification Office, 1601 Lind Avenue, SW., 

Renton, Washington 98057–3356; telephone 

(425) 917–6440; fax (425) 917–6590; or e-mail 

information to 9-ANM-Seattle-ACO-AMOCRequests@faa.gov. 

(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. 

(3) An AMOC that provides an acceptable 

level of safety may be used for any repair 

required by this AD, if it is approved by an 

Authorized Representative for the Boeing 

Commercial Airplanes Delegation Option 

Authorization Organization who has been 

authorized by the Manager, Seattle ACO, to 

make those findings. For a repair method to 

be approved the repair must meet the 

certification basis of the airplane, and the 

approval must specifically refer to this AD. 

Material Incorporated by Reference 

(j) You must use Boeing Service Bulletin 

737–32A1355, Revision 2, dated March 5, 

2008, 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; telephone 206– 

544–9990; fax 206–766–5682; e-mail 

DDCS@boeing.com; Internet https:// 

www.myboeingfleet.com. 

(3) 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 or 425–227–1152. 

(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 NARA, call 202–741–6030, or go 

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

code_of_federal_regulations/ 

ibr_locations.html. 

21254 Federal Register / Vol. 74, No. 87 / Thursday, May 7, 2009 / Rules and Regulations 

Issued in Renton, Washington, on April 22, 

2009. 

Stephen P. Boyd, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. E9–9926 Filed 5–6–09; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2008–1275; Directorate 

Identifier 2007–NM–167–AD; Amendment 

39–15892; AD 2009–09–06] 

RIN 2120–AA64 

Airworthiness Directives; Boeing 

Model 737–100, –200, –200C, –300, 

–400, and –500 Series Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for certain 

Boeing Model 737–100, –200, –200C, 

–300, –400, and –500 series airplanes. 

This AD requires repetitive detailed and 

high frequency eddy current inspections 

to detect cracks of the backup 

intercostals and the upper sill of the 

forward airstair doorway, and 

applicable corrective actions. This AD 

also provides for an optional 

terminating action, which would 

eliminate the need for repetitive 

inspections. This AD results from a 

report indicating that cracks were found 

in the backup intercostals and upper sill 

web of the forward airstair doorway. We 

are issuing this AD to detect and correct 

fatigue cracking of the backup 

intercostals and upper sill web of the 

forward airstair doorway, which could 

result in a rapid loss of cabin pressure. 

DATES: This AD is effective June 11, 

2009. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in the AD 

as of June 11, 2009. 

ADDRESSES: For service information 

identified in this AD, contact Boeing 

Commercial Airplanes, Attention: Data 

& Services Management, P.O. Box 3707, 

MC 2H–65, Seattle, Washington 98124– 

2207; telephone 206–544–5000, 

extension 1; fax 206–766–5680; e-mail 

me.boecom@boeing.com; Internet&fnl; 

https://www.myboeingfleet.com. 

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 address for the 

Docket Office (telephone 800–647–5527) 

is the Document Management Facility, 

U.S. Department of Transportation, 

Docket Operations, M–30, West 

Building Ground Floor, Room W12–140, 

1200 New Jersey Avenue, SE., 

Washington, DC 20590. 

FOR FURTHER INFORMATION CONTACT: 

Alan Pohl, Aerospace Engineer, 

Airframe Branch, ANM–120S, FAA, 

Seattle Aircraft Certification Office, 

1601 Lind Avenue, SW., Renton, 

Washington 98057–3356; telephone 

(425) 917–6450; fax (425) 917–6590. 

SUPPLEMENTARY INFORMATION: 

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 737–100, –200, 

–200C, –300, –400, and –500 series 

airplanes. That NPRM was published in 

the Federal Register on December 5, 

2008 (73 FR 74080). That NPRM 

proposed to require repetitive detailed 

and high frequency eddy current 

inspections to detect cracks of the 

backup intercostals and the upper sill of 

the forward airstair doorway, and 

applicable corrective actions. That 

NPRM also provided an optional 

terminating action, which would 

eliminate the need for repetitive 

inspections. 

Comments 

We gave the public the opportunity to 

participate in developing this AD. We 

considered the comments received from 

the two commenters. 

Support for the NPRM 

Boeing concurs with the contents of 

the NPRM. 

Request for Clarification 

Southwest Airlines requests more 

information regarding alternative 

procedures for airplanes that have had 

the airstair door deactivated per Boeing 

Service Bulletin 737–52–1092. 

Southwest Airlines asks whether 

instructions developed by operators, for 

open and close of an airstair door after 

deactivation per Boeing Service Bulletin 

737–52–1092, will be considered 

approved equivalent procedures. 

No alternative procedures have been 

established that have general FAA 

approval; however, according to the 

provisions of paragraph (h) of the final 

rule we may approve requests for 

different compliance methods if the 

requests include data that prove that the 

new methods would provide an 

acceptable level of safety. 

Conclusion 

We reviewed the relevant data, 

considered the comments received, and 

determined that air safety and the 

public interest require adopting the AD 

as proposed. 

Costs of Compliance 

There are 1,712 airplanes of the 

affected design in the worldwide fleet. 

This AD affects 509 airplanes of U.S. 

registry. The inspections take 2 work 

hours per airplane, at an average labor 

rate of $80 per work hour. Based on 

these figures, the estimated cost of the 

AD for U.S. operators is $81,440, or 

$160 per airplane, per inspection cycle. 

The optional terminating action, if 

done, would take 9 work hours, at an 

average labor rate of $80 per work hour. 

Required parts cost between $533 and 

$566 per airplane, depending on the 

airplane configuration. Based on these 

figures, the estimated cost of the 

optional terminating action would range 

between $1,253 and $1,286 per airplane, 

depending on the airplane 

configuration. 

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