5918 Federal Register / Vol. 69, No. 26 / Monday, February 9, 2004 / Rules and Regulations 

TABLE 2.—PREVIOUSLY APPROVED SERVICE BULLETINS—Continued

Service bulletin Revision level Date 

ATR72–53–1020 .................................................................... Original .................................................................................. October 6, 1992. 

ATR72–53–1021 .................................................................... Revision 1 ............................................................................. February 20, 1995. 

(3) Copies may be obtained from 

Aerospatiale, 316 Route de Bayonne, 31060 

Toulouse, Cedex 03, France. Copies may be 

inspected at the FAA, Transport Airplane 

Directorate, 1601 Lind Avenue, SW., Renton, 

Washington; or at the Office of the Federal 

Register, 800 North Capitol Street, NW., suite 

700, Washington, DC.

Note 3: The subject of this AD is addressed 

in French airworthiness directive 2001–142–

056(B), dated April 18, 2001.

Effective Date 

(m) This amendment becomes effective on 

March 15, 2004.

Issued in Renton, Washington, on January 

29, 2004. 

Kalene C. Yanamura, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service.

[FR Doc. 04–2586 Filed 2–6–04; 8:45 am] 

BILLING CODE 4910–13–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration 

14 CFR Part 39

[Docket No. 2001–NM–366–AD; Amendment 

39–13452; AD 2004–03–08] 

RIN 2120–AA64

Airworthiness Directives; Learjet 

Model 31, 31A, 35, 35A (C–21A), 36, 

and 36A Airplanes

AGENCY: Federal Aviation 

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a 

new airworthiness directive (AD), 

applicable to certain Learjet Model 31, 

31A, 35, 35A (C–21A), 36, and 36A 

airplanes, that requires modification of 

the drag angles of the fuselage and 

engine pylons to gain access to the shear 

webs of the forward engine beams; 

repetitive inspections of the shear webs 

of the forward engine beams for cracks; 

follow-on actions; and modification/

repair of the shear webs of the forward 

engine beams, as necessary, which 

terminates the repetitive inspections. 

This action is necessary to prevent 

significant structural damage to the 

engine pylons, possible separation of 

the engines from the fuselage, and 

consequent reduced controllability of 

the airplane. This action is intended to 

address the identified unsafe condition.

DATES: Effective March 15, 2004. 

The incorporation by reference of 

certain publications listed in the 

regulations is approved by the Director 

of the Federal Register as of March 15, 

2004.

ADDRESSES: The service information 

referenced in this AD may be obtained 

from Learjet, Inc., One Learjet Way, 

Wichita, Kansas 67209–2942. This 

information may be examined at the 

Federal Aviation Administration (FAA), 

Transport Airplane Directorate, Rules 

Docket, 1601 Lind Avenue, SW., 

Renton, Washington; or at the FAA, 

Wichita Aircraft Certification Office, 

1801 Airport Road, Room 100, MidContinent Airport, Wichita, Kansas; or 

at the Office of the Federal Register, 800 

North Capitol Street, NW., suite 700, 

Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Steven Litke, Aerospace Engineer, 

Airframe Branch, ACE–118W, FAA, 

Wichita Aircraft Certification Office, 

1801 Airport Road, Room 100, MidContinent Airport, Wichita, Kansas 

67209; telephone (316) 946–4127; fax 

(316) 946–4107.

SUPPLEMENTARY INFORMATION: A 

proposal to amend part 39 of the Federal 

Aviation Regulations (14 CFR part 39) to 

include an airworthiness directive (AD) 

that is applicable to certain Learjet 

Model 31, 31A, 35, 35A (C–21A), 36, 

and 36A airplanes was published in the 

Federal Register on November 13, 2003 

(68 FR 64283). That action proposed to 

require modification of the drag angles 

of the fuselage and engine pylons to 

gain access to the shear webs of the 

forward engine beams; repetitive 

inspections of the shear webs of the 

forward engine beams for cracks; followon actions; and modification/repair of 

the shear webs of the forward engine 

beams, as necessary, which would 

terminate the repetitive inspections. 

Comments 

Interested persons have been afforded 

an opportunity to participate in the 

making of this amendment. No 

comments were submitted in response 

to the proposal or the FAA’s 

determination of the cost to the public. 

Conclusion 

We have determined that air safety 

and the public interest require the 

adoption of the rule as proposed. 

Cost Impact 

There are approximately 893 

airplanes of the affected design in the 

worldwide fleet. We estimate that 673 

airplanes of U.S. registry will be affected 

by this AD. 

It will take between 2 and 3 work 

hours per airplane to accomplish the 

required modification, at an average 

labor rate of $65 per work hour. 

Required parts will cost approximately 

$243 per airplane. Based on these 

figures, the cost impact of the required 

modification on U.S. operators is 

estimated to be between $251,029 and 

$294,774, or between $373 and $438 per 

airplane. 

We estimate that it will take 3 work 

hours to perform the required 

inspections, and that the average labor 

rate is $65 per work hour. Based on this 

figure, the cost impact of the required 

inspections on U.S. operators is 

estimated to be $131,235, or $195 per 

airplane, per inspection cycle. 

The cost impact figures discussed 

above are based on assumptions that no 

operator has yet accomplished any of 

the requirements of this AD action, and 

that no operator would accomplish 

those actions in the future if this AD 

were not adopted. The cost impact 

figures discussed in AD rulemaking 

actions represent only the time 

necessary to perform the specific actions 

actually required by the AD. These 

figures typically do not include 

incidental costs, such as the time 

required to gain access and close up, 

planning time, or time necessitated by 

other administrative actions. The 

manufacturer may cover the cost of 

replacement parts associated with this 

AD, subject to warranty conditions. 

Manufacturer warranty remedies may 

also be available for labor costs 

associated with this AD. As a result, the 

costs attributable to this AD may be less 

than stated above. 

Regulatory Impact 

The regulations adopted herein 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 

Federal Register / Vol. 69, No. 26 / Monday, February 9, 2004 / Rules and Regulations 5919

responsibilities among the various 

levels of government. Therefore, it is 

determined that this final rule does not 

have federalism implications under 

Executive Order 13132. 

For the reasons discussed above, I 

certify that this action (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. A final evaluation has 

been prepared for this action and it is 

contained in the Rules Docket. A copy 

of it may be obtained from the Rules 

Docket at the location provided under 

the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation 

safety, Incorporation by reference, 

Safety.

Adoption of the Amendment

■ Accordingly, pursuant to the authority 

delegated to me by the Administrator, 

the Federal Aviation Administration 

amends part 39 of the Federal Aviation 

Regulations (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. Section 39.13 is amended by adding 

the following new airworthiness 

directive:

2004–03–08 Learjet: Amendment 39–13452. 

Docket 2001–NM–366–AD.

Applicability: The following airplanes, 

certificated in any category, as applicable:

TABLE 1.—APPLICABILITY

Model— As Listed in Bombardier Service Bulletin—

31 and 31A Airplanes ......................................... 31–51–2, dated February 1, 2001; and 31–51–3, Revision 1, dated August 2, 2001. 

35, 35A (C–21A), 36 and 36A Airplanes ............ 35/36–51–3, dated February 1, 2001; and 35/36–51–4, Revision 1, dated August 2, 2001. 

Compliance: Required as indicated, unless 

accomplished previously. 

To prevent significant structural damage to 

the engine pylons, possible separation of the 

engines from the fuselage, and consequent 

reduced controllability of the airplane, 

accomplish the following: 

Inspections 

(a) At the later of the times specified in 

paragraphs (a)(1) and (a)(2) of this AD: Do a 

detailed inspection (using a probe) and a 

general visual inspection of the shear webs 

of the forward engine beams (including 

modification of the drag angles) for cracking 

in accordance with the Accomplishment 

Instructions of Bombardier Service Bulletin 

31–51–2 (for Model 31 airplanes) or 35/36–

51–3 (for Model 35 and 36 airplanes), both 

dated February 1, 2001; as applicable. 

(1) Prior to the accumulation of 3,000 total 

flight hours; or 

(2) Within 1,200 flight hours or 1 year after 

the effective date of this AD, whichever 

occurs first.

Note 1: For the purposes of this AD, a 

general visual inspection is defined as: ‘‘A 

visual 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 enhance visual 

access to all exposed 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: For the purposes of this AD, a 

detailed inspection is defined as: ‘‘An 

intensive visual examination of a specific 

structural area, system, installation, or 

assembly to detect damage, failure, or 

irregularity. Available lighting is normally 

supplemented with a direct source of good 

lighting at intensity deemed appropriate by 

the inspector. Inspection aids such as mirror, 

magnifying lenses, etc., may be used. Surface 

cleaning and elaborate access procedures 

may be required.’’

Detailed Probe Inspection Follow-On 

Actions 

(b) Following the detailed probe inspection 

required by paragraph (a) of this AD, do the 

follow-on actions specified in paragraphs 

(b)(1), (b)(2), or (b)(3) of this AD, as 

applicable, in accordance with the 

Accomplishment Instructions of Bombardier 

Service Bulletin 31–51–2 or 35/36–51–3, 

both dated February 1, 2001; as applicable. 

(1) If the resistance measured during the 

inspection is less than 0.110 milliohm: 

Repeat the inspections required by paragraph 

(a) of this AD thereafter at intervals not to 

exceed 1,200 flight hours. 

(2) If the resistance measured during the 

inspection is 0.110 milliohm or more, but 

less than 0.150 milliohm: Within the next 

1,200 flight hours, repair and modify the 

forward engine beam shear web in 

accordance with the Accomplishment 

Instructions of Bombardier Service Bulletin 

31–51–3, Revision 1 (for Model 31 airplanes) 

or 35/36–51–4, Revision 1 (for Model 35 and 

36 airplanes), both dated August 2, 2001; as 

applicable. 

(3) If the resistance measured during the 

inspection is 0.150 milliohm or more: Before 

further flight, repair and modify the forward 

engine beam shear web in accordance with 

the Accomplishment Instructions of 

Bombardier Service Bulletin 31–51–3, 

Revision 1, or 35/36–51–4, Revision 1; as 

applicable. 

General Visual Inspection Follow-On 

Actions 

(c) Following the general visual inspection 

required by paragraph (a) of this AD, do all 

of the applicable follow-on actions at the 

times specified in the Accomplishment 

Instructions of Bombardier Service Bulletin 

31–51–2 or 35/36–51–3, both dated February 

1, 2001; as applicable; except as specified in 

paragraph (d) of this AD. 

(d) If any crack opening is found that is 

more than 0.03 inch during the general visual 

inspection required by paragraph (a) of this 

AD: Before further flight, do the actions 

specified in paragraphs 2.C.(16)(a) and 

2.C.(16)(b) of Bombardier Service Bulletin 

31–51–2 or 35/36–51–3, both dated February 

1, 2001; as applicable; repair per a method 

approved by the Manager, Wichita Aircraft 

Certification Office (ACO), FAA; and do the 

terminating action specified in paragraph (e) 

of this AD. 

Terminating Action 

(e) Modification of the shear webs by 

accomplishing all of the actions specified in 

the Accomplishment Instructions of 

Bombardier Service Bulletin 31–51–3, 

Revision 1, or 35/36–51–4, Revision 1, both 

dated August 2, 2001; as applicable; 

terminates the initial inspections required by 

paragraph (a) and the repetitive inspections 

required by paragraph (b)(1) of this AD. 

Repair Approval 

(f) Where any service bulletin identified in 

this AD specifies that the manufacturer may 

be contacted for disposition of certain repair 

conditions, repair per a method approved by 

the Manager, Wichita ACO, FAA. 

Submission of Inspection Results Not 

Required 

(g) Although the service bulletins 

identified in this AD specify to submit 

information to the manufacturer, this AD 

does not include such a requirement. 

Alternative Methods of Compliance 

(h) In accordance with 14 CFR 39.19, the 

Manager, Wichita ACO, is authorized to 

approve alternative methods of compliance 

for this AD. 

5920 Federal Register / Vol. 69, No. 26 / Monday, February 9, 2004 / Rules and Regulations 

Incorporation by Reference 

(i) Unless otherwise specified in this AD, 

the actions shall be done in accordance with 

Bombardier Service Bulletin 31–51–2, dated 

February 1, 2001, and Bombardier Service 

Bulletin 31–51–3, Revision 1, dated August 

2, 2001; or Bombardier Service Bulletin 35/

36–51–3, dated February 1, 2001, and 

Bombardier Service Bulletin 35/36–51–4, 

Revision 1, dated August 2, 2001; as 

applicable. This incorporation by reference 

was approved by the Director of the Federal 

Register in accordance with 5 U.S.C. 552(a) 

and 1 CFR part 51. Copies may be obtained 

from Learjet, Inc., One Learjet Way, Wichita, 

Kansas 67209–2942. Copies may be inspected 

at the FAA, Transport Airplane Directorate, 

1601 Lind Avenue, SW., Renton, 

Washington; or at the FAA, Wichita Aircraft 

Certification Office, 1801 Airport Road, 

Room 100, Mid-Continent Airport, Wichita, 

Kansas; or at the Office of the Federal 

Register, 800 North Capitol Street, NW., suite 

700, Washington, DC. 

Effective Date 

(j) This amendment becomes effective on 

March 15, 2004.

Issued in Renton, Washington, on January 

29, 2004. 

Kalene C. Yanamura, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service.

[FR Doc. 04–2585 Filed 2–6–04; 8:45 am] 

BILLING CODE 4910–13–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. 2001–NM–278–AD; Amendment 

39–13455; AD 2004–03–11] 

RIN 2120–AA64 

Airworthiness Directives; Boeing 

Model 747–200C and –200F Series 

Airplanes

AGENCY: Federal Aviation 

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a 

new airworthiness directive (AD), 

applicable to certain Boeing Model 747–

200C and –200F series airplanes, that 

requires repetitive inspections to find 

fatigue cracking in the upper chord of 

the upper deck floor beams, and repair 

if necessary. For certain airplanes, this 

amendment also provides an optional 

repair/modification, which extends 

certain repetitive inspection intervals. 

This action is necessary to find and fix 

cracking in certain upper deck floor 

beams. Such cracking could extend and 

sever floor beams at a floor panel 

attachment hole location and could 

result in rapid decompression and 

consequent loss of controllability of the 

airplane. This action is intended to 

address the identified unsafe condition.

DATES: Effective March 15, 2004. 

The incorporation by reference of a 

certain publication listed in the 

regulations is approved by the Director 

of the Federal Register as of March 15, 

2004.

ADDRESSES: The service information 

referenced in this AD may be obtained 

from Boeing Commercial Airplanes, 

P.O. Box 3707, Seattle, Washington 

98124–2207. This information may be 

examined at the Federal Aviation 

Administration (FAA), Transport 

Airplane Directorate, Rules Docket, 

1601 Lind Avenue, SW., Renton, 

Washington; or at the Office of the 

Federal Register, 800 North Capitol 

Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Rick 

Kawaguchi, Aerospace Engineer, 

Airframe Branch, ANM–120S, FAA, 

Seattle Aircraft Certification Office, 

1601 Lind Avenue, SW., Renton, 

Washington 98055–4056; telephone 

(425) 917–6434; fax (425) 917–6590.

SUPPLEMENTARY INFORMATION: A 

proposal to amend part 39 of the Federal 

Aviation Regulations (14 CFR part 39) to 

include an airworthiness directive (AD) 

that is applicable to certain Boeing 

Model 747–200C and –200F series 

airplanes was published in the Federal 

Register on July 24, 2003 (68 FR 43688). 

That action proposed to require 

repetitive inspections to find fatigue 

cracking in the upper chord of the upper 

deck floor beams, and repair if 

necessary. For certain airplanes, that 

action also proposed an optional repair/

modification, which would extend 

certain repetitive inspection intervals. 

Comments 

Interested persons have been afforded 

an opportunity to participate in the 

making of this amendment. Due 

consideration has been given to the 

comments received. 

Request To Allow an Additional 

Adjustment to the Compliance Time 

One commenter requests that 

adjustments to the compliance time in 

paragraph (c) of the proposed AD 

should apply not only to the actions 

described in paragraph (a), but also to 

those described in paragraph (b). 

The FAA concurs. We find that relief 

of the cabin pressure differential should 

be applicable to the compliance 

thresholds and repetitive inspections for 

the optional action described in 

paragraph (b) as well as those required 

by paragraph (a). Paragraph (c) of this 

final rule has been changed accordingly. 

Request To Expand Provisions for 

Optional Repair/Modification 

One commenter suggests that 

paragraph (b) of the proposed AD be 

revised to provide that, if the inspection 

required by paragraph (a) of the 

proposed AD were done per Part 2 

Surface High Frequency Eddy Current 

(HFEC) Inspection Method of the Work 

Instructions of Boeing Alert Service 

Bulletin 747–53A2439, then 

accomplishment of the optional repair 

or modification specified in paragraph 

(b)(1) of the proposed AD could be 

performed. The commenter indicates 

that repair per paragraph (b)(1) of the 

proposed AD already requires open-hole 

HFEC inspection of the floor panel hole 

and reworking of the hole, until any 

cracking is removed. It should, 

therefore, be acceptable to accomplish 

repair following inspection per Part 2 of 

the Work Instructions of the service 

bulletin. 

The FAA agrees that repair per 

paragraph (b)(1) of the proposed AD 

requires open hole HFEC inspection of 

the floor panel hole and re-working of 

the hole, until any cracking is removed. 

We find, therefore, that following 

inspection per Part 2 of the Work 

Instructions of the service bulletin, the 

repair may be accomplished per 

paragraph (b)(1). We have revised 

paragraph (b) of the final rule 

accordingly. 

Request To Clarify Location of Fatigue 

Cracking 

One commenter asks that the 

Discussion section of the proposed AD 

be revised to refer to STA 420, rather 

than STA 340. The commenter also asks 

that the language in the Discussion 

section and in the third paragraph of the 

introduction of the proposed AD be 

changed from ‘‘* * * could extend and 

sever floor beams adjacent to the body 

frame * * *’’ to ‘‘* * * could extend 

and sever floor beams at a floor panel 

hole location * * *.’’

The commenter notes that the 

Background section of Boeing Alert 

Service Bulletin 747–53A2439 indicates 

that fatigue cracking was reported at 

STA 420 rather than at STA 340. The 

commenter also notes that the 

applicable inspections and possible 

repair or modification is at the upper 

deck floor beam floor panel attachment 

holes, which exist throughout the span 

of the floor beams, not just adjacent to 

where the floor beam joins the body 

frame. 

The FAA partially concurs with the 

comment. No change is needed in the 

Discussion section, since that section is 

not restated in this final rule. In terms