61478 Federal Register / Vol. 67, No. 190 / Tuesday, October 1, 2002 / Rules and Regulations 

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.’’

(1) If no cracking is detected, repeat the 

inspection thereafter at intervals not to 

exceed 18 months. 

(2) If any cracking is detected, prior to 

further flight, replace the cracked tube with 

a new or serviceable part, in accordance with 

Boeing Alert Service Bulletin 747–26A2266, 

dated March 3, 2000. Repeat the inspection 

required by paragraph (a) of this AD within 

18 months after the replacement and 

thereafter at intervals not to exceed 18 

months.

New Requirements of This AD 

Modification—Airplanes With Pratt & 

Whitney PW4000 Engines 

(b) For Model 747–400 and 747–400F 

series airplanes equipped with Pratt & 

Whitney PW4000 engines: Within 24 months 

after the effective date of this AD, modify the 

routing of the fire extinguishing tubes 

between the inboard fire bottles and the 

inboard engines in accordance with Boeing 

Service Bulletin 747–26–2233, dated May 11, 

1995; or Boeing Alert Service Bulletin 747–

26A2233, Revision 1, dated November 16, 

2000. Accomplishment of the requirements 

of this paragraph constitutes terminating 

action for the repetitive inspections required 

by paragraph (a) of this AD for Model 747–

400 and 747–400F series airplanes equipped 

with Pratt & Whitney PW4000 engines. 

Modification—Airplanes With General 

Electric CF6–80C2 Series Engines 

(c) For 747–200B, –300, –400, –400D, and 

–400F series airplanes equipped with 

General Electric CF6–80C2 series engines: 

Within 24 months after the effective date of 

this AD, modify the routing of the fire 

extinguishing tubes between the inboard fire 

bottles and the inboard engines in 

accordance with Boeing Alert Service 

Bulletin 747–26A2267, dated December 20, 

2000. Accomplishment of the requirements 

of this paragraph constitutes terminating 

action for the repetitive inspections required 

by paragraph (a) of this AD for Model 747–

200B, –300, –400, –400D, and –400F series 

airplanes equipped with General Electric 

CF6–80C2 engines. 

Alternative Methods of Compliance 

(d) An alternative method of compliance or 

adjustment of the compliance time that 

provides an acceptable level of safety may be 

used if approved by the Manager, Seattle 

Aircraft Certification Office (ACO), FAA. 

Operators shall submit their requests through 

an appropriate FAA Principal Maintenance 

Inspector, who may add comments and then 

send it to the Manager, Seattle ACO.

Note 3: Information concerning the 

existence of approved alternative methods of 

compliance with this AD, if any, may be 

obtained from the Seattle ACO.

Special Flight Permits 

(e) Special flight permits may be issued in 

accordance with §§ sections 21.197 and 

21.199 of the Federal Aviation Regulations 

(14 CFR 21.197 and 21.199) to operate the 

airplane to a location where the requirements 

of this AD can be accomplished. 

Incorporation by Reference 

(f) The actions shall be done in accordance 

with Boeing Alert Service Bulletin 747–

26A2266, dated March 3, 2000; Boeing 

Service Bulletin 747–26–2233, dated May 11, 

1995, or Boeing Alert Service Bulletin 747–

26A2233, Revision 1, dated November 16, 

2000; and Boeing Alert Service Bulletin 747–

26A2267, dated December 20, 2000; as 

applicable. 

(1) The incorporation by reference of 

Boeing Alert Service Bulletin 747–26A2233, 

Revision 1, dated November 16, 2000; and 

Boeing Alert Service Bulletin 747–26A2267, 

dated December 20, 2000; is approved by the 

Director of the Federal Register, in 

accordance with 5 U.S.C. 552(a) and 1 CFR 

part 51. 

(2) The incorporation by reference of 

Boeing Alert Service Bulletin 747–26A2266, 

dated March 3, 2000; and Boeing Service 

Bulletin 747–26–2233, dated May 11, 1995; 

was approved previously by the Director of 

the Federal Register as of April 25, 2000 (65 

FR 18881, April 10, 2000). 

(3) Copies may be obtained from Boeing 

Commercial Airplane Group, P.O. Box 3707, 

Seattle, Washington 98124–2207. 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. 

Effective Date 

(g) This amendment becomes effective on 

November 5, 2002.

Issued in Renton, Washington, on 

September 19, 2002. 

Vi L. Lipski, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service.

[FR Doc. 02–24406 Filed 9–30–02; 8:45 am] 

BILLING CODE 4910–13–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. 2001–NM–268–AD; Amendment 

39–12891; AD 2002–19–11] 

RIN 2120–AA64 

Airworthiness Directives; Boeing 

Model 767–200 and –300 Series 

Airplanes Powered by Pratt & Whitney 

JT9D Series Engines

AGENCY: Federal Aviation 

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a 

new airworthiness directive (AD), 

applicable to certain Boeing Model 767–

200 and –300 series airplanes powered 

by Pratt & Whitney JT9D series engines, 

that requires replacement of the existing 

deactivation pin, aft cascade pin 

bushing, and pin insert on each thrust 

reverser half, with new, improved 

components. This action is necessary to 

prevent failure of the thrust reverser 

deactivation pins, which could result in 

deployment of the thrust reverser in 

flight and consequent reduced 

controllability of the airplane. This 

action is intended to address the 

identified unsafe condition.

DATES: Effective November 5, 2002. 

The incorporation by reference of 

certain publications listed in the 

regulations is approved by the Director 

of the Federal Register as of November 

5, 2002.

ADDRESSES: The service information 

referenced in this AD may be obtained 

from Boeing Commercial Airplane 

Group, 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:

Technical Information: John Vann, 

Aerospace Engineer, Propulsion Branch, 

ANM–140S, FAA, Seattle Aircraft 

Certification Office, 1601 Lind Avenue, 

SW., Renton, Washington 98055–4056; 

telephone (425) 227–1024; fax (425) 

227–1181. 

Other Information: Judy Golder, 

Airworthiness Directive Technical 

Editor/Writer; telephone (425) 687–

4241, fax (425) 227–1232. Questions or 

comments may also be sent via the 

Internet using the following address: 

judy.golder@faa.gov. Questions or 

comments sent via the Internet as 

attached electronic files must be 

formatted in Microsoft Word 97 for 

Windows or ASCII text.

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 767–200 and –300 series 

airplanes powered by Pratt & Whitney 

(P&W) JT9D series engines was 

published in the Federal Register on 

November 19, 2001 (66 FR 57904). That 

action proposed to require replacement 

of the existing deactivation pin, aft 

cascade pin bushing, and pin insert on 

each thrust reverser half, with new, 

improved components.

Federal Register / Vol. 67, No. 190 / Tuesday, October 1, 2002 / Rules and Regulations 61479

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. 

Support for the Proposed AD 

One commenter supports the 

proposed AD, and notes that the design 

of the thrust reverser system on Model 

767 series airplanes powered by P&W 

JT9D series engines is similar to that on 

Model 767 series airplanes equipped 

with P&W PW4000 series engines.

Disagreement With Proposed AD/

Request for Withdrawal 

Two commenters disagree with the 

proposed AD, and one of these 

commenters requests that the FAA 

withdraw the proposal. 

Both commenters note that the 

proposed AD is prompted by partial 

deployment of the thrust reversers on 

airplanes equipped with P&W PW4000 

series airplanes, and no similar 

incidents have occurred on airplanes 

equipped with P&W JT9D series 

engines. The commenters emphasize 

that there are significant differences in 

design and function between the thrust 

reverser systems on these two engine 

models. Both commenters point out 

that, while the thrust reverser system on 

Model 767 P&W PW4000 series engines 

incorporates two hydraulic isolation 

valves—a motorized hydraulic isolation 

valve for deployment and a hydraulic 

stow valve for stowage, the thrust 

reverser system on Model 767 P&W 

JT9D series engines has only a hydraulic 

isolation valve, and no motorized 

isolation valve. The commenters 

maintain that the differences between 

the thrust reverser systems on the two 

engine models make the identified 

unsafe condition unique to P&W 

PW4000 series engines. 

As further evidence of this, the 

commenters emphasize that the 

previous incidents occurred due to 

improper deactivation of the motorized 

isolation valve in the thrust reverser 

system by maintenance personnel who 

were not properly trained or did not 

follow procedures for proper 

deactivation of the thrust reverser 

system. Finally, both commenters point 

out that all previous incidents have 

occurred after landing during a 

commanded thrust reverser deployment, 

and they assert that this is not a safetyof-flight concern, but an economic 

concern (i.e., potential significant 

damage to the thrust reverser sleeves). 

We do not concur with the request to 

withdraw the proposed AD. Although 

we recognize that there are differences 

between the two thrust reverser systems, 

we find that the similarities between the 

two thrust reverser systems make 

airplanes powered by JT9D series 

engines potentially subject to the 

identified unsafe condition. We note 

that the airplane manufacturer also 

considers these similarities sufficient to 

create the risk of an in-flight 

deployment of a thrust reverser. 

Also, while we acknowledge that all 

previous incidents on Model 767 series 

airplanes powered by P&W PW4000 

series engines occurred after landing, 

the airplane manufacturer has reported 

an incident of a partial in-flight 

deployment on a Model 747–400 series 

airplane powered by P&W PW4000 

series engines. That incident has been 

attributed to improper deactivation of 

the thrust reverser. When deactivated, 

the thrust reverser is restrained by 

locking the hydraulic valve, locking and 

deactivating the sync lock, and inserting 

the deactivation pin. However, 

maintenance crews occasionally will 

improperly deactivate the hydraulic 

valve or sync lock, leaving only the 

structural integrity of the deactivation 

pin as protection from in-flight 

deployment. Considering the criticality 

of a deployment of a thrust reverser in 

mid-flight, we consider this a safety-offlight issue. 

Further, we acknowledge the 

commenters’ remarks on training and 

supervision deficiencies. While 

increased training and proper 

supervision can alleviate the noted 

problems, current levels of training and 

supervision have not reduced the 

incidents of improper maintenance to 

an acceptable level. 

For the reasons stated previously, we 

find that no change to the final rule is 

necessary in this regard. 

Acknowledge Errors in the Work 

Instructions in Service Bulletin 

The commenter that urges us to 

withdraw the proposed AD (as 

described in the previous section) states 

that the Work Instructions in Boeing 

Alert Service Bulletin 767–78A0089, 

dated July 19, 2001, cannot be 

accomplished on the thrust reverser 

system on Model 767 P&W JT9D series 

engines. The commenter points out that 

certain steps in the work instructions 

refer to components that do not exist on 

Model 767 P&W JT9D series engines. As 

noted previously, while the thrust 

reverser system on Model 767 P&W 

PW4000 series engines has two 

hydraulic isolation valves—a motorized 

hydraulic isolation valve for 

deployment and a hydraulic stow valve 

for stowage, the thrust reverser system 

on Model 767 P&W JT9D series engines 

has only a hydraulic isolation valve, no 

motorized isolation valve. Therefore, for 

example, the instruction in paragraph 

3.B.4. of Boeing Alert Service Bulletin 

767–78A0089 to ‘‘Deactivate the 

Motorized Isolation Valve and the Stow 

Valve * * *’’ cannot be done because 

there are not two valves to deactivate on 

the thrust reverser system on Model 767 

P&W JT9D series engines. 

These observations were part of the 

commenter’s request for us to withdraw 

the proposed AD. We do not concur 

with this request. However, we 

acknowledge that the wording of the 

instructions in paragraphs 3.B.4. and 

3.L.1. of Boeing Alert Service Bulletin 

767–78A0089 is somewhat confusing. 

Since we issued the notice of 

proposed rulemaking (NPRM), Boeing 

has issued Alert Service Bulletin 767–

78A0089, Revision 1, dated May 30, 

2002. Among other changes, Revision 1 

of the service bulletin corrects the errors 

in the work instructions of the original 

issue of the service bulletin to which the 

commenter refers. Therefore, for 

clarification, we find it appropriate to 

revise paragraph (a) of this final rule to 

refer to Revision 1 of the service bulletin 

as the appropriate source of service 

information for the actions required by 

that paragraph. Also, we have added a 

new paragraph (b) to this final rule to 

state that replacements accomplished 

before the effective date of this AD 

according to the original issue of the 

service bulletin are acceptable for 

compliance with this AD. 

Allow Modification During In-Shop 

Maintenance 

One commenter requests that we 

revise the instructions of the referenced 

service bulletin to allow 

accomplishment of the replacement 

during maintenance, while the engine 

nacelle is off the wing, rather than with 

the engine nacelle mounted on the wing 

of the airplane. The commenter states 

that the service bulletin does not 

provide appropriate procedures for 

doing this. Specifically, the commenter 

requests that we revise the instructions 

in the service bulletin to provide for 

accomplishment of paragraphs 3.C. to 

3.K. of the Work Instructions of the 

referenced service bulletin in the shop. 

We agree that the service bulletin 

instructions need to be revised. As 

stated previously, since the issuance of 

the NPRM, Boeing has issued Revision 

1 of the service bulletin. In addition to 

the changes explained previously, 

Revision 1 of the service bulletin adds 

a new Work Package III, which provides 

the instructions for modification of a 

spare thrust reverser that the commenter

61480 Federal Register / Vol. 67, No. 190 / Tuesday, October 1, 2002 / Rules and Regulations 

requests. We previously explained that 

we have revised paragraph (a) of this 

final rule to refer to Revision 1 of the 

service bulletin as the appropriate 

source of service information for the 

actions required by that paragraph, and 

we have added paragraph (b) to this 

final rule to give credit for replacements 

accomplished before the effective date 

of this AD according to the original 

issue of the service bulletin. Therefore, 

no further change to this final rule is 

necessary. 

Limit Number of Tests 

The same commenter requests that we 

reduce the number of post-replacement 

test cycles (extension and retraction of 

the thrust reverser to make sure it 

operates correctly), from three times, as 

specified in the service bulletin, to one 

time. The commenter states that, if the 

replacement is done with the engine 

nacelle in the shop rather than mounted 

on the wing, three test cycles are not 

necessary. 

We do not concur. The commenter 

provides no data to justify its request, 

and we see no advantage to reducing the 

number of test cycles from three to one. 

However, if an operator considers that 

such a reduction in the number of test 

cycles will provide an acceptable level 

of safety, the operator may request 

approval of an alternative method of 

compliance with this testing 

requirement, as provided by paragraph 

(c) of this AD. No change to the final 

rule is necessary in this regard.

Reduce Compliance Time 

One commenter is concerned that the 

compliance time of 24 months allowed 

by the proposed AD may be too long. 

The commenter states, however, that it 

assumes that the FAA has carried out an 

appropriate risk assessment to justify 

the proposed compliance time. 

We infer that the commenter is 

requesting that we reduce the proposed 

compliance time for the actions required 

by this AD. We do not concur. The 

commenter provides no data to justify 

its statement that the proposed 

compliance time may be too long. As 

stated in the proposed AD, in 

developing an appropriate compliance 

time for this AD, we considered not 

only the manufacturer’s 

recommendation, but the degree of 

urgency associated with addressing the 

subject unsafe condition, the average 

utilization of the affected fleet, and the 

time necessary to perform the 

replacement. In light of these factors, we 

find that 24 months is an appropriate 

interval to allow affected airplanes to 

continue to operate without 

compromising safety. No change to the 

final rule is necessary in this regard. 

Extend Compliance Time 

One commenter requests that we 

extend the compliance time for the 

proposed requirements from 24 months 

to 30 months. The commenter states that 

it would like to do the proposed 

replacement during a scheduled 

maintenance visit, but sufficient parts 

may not be available to allow for this. 

We do not concur with the request to 

extend the compliance time for the 

actions required by this AD. Based on 

the latest information provided to us by 

the airplane manufacturer, an ample 

supply of required parts will be 

available within the 24-month 

compliance period. As stated 

previously, we find that 24 months is an 

appropriate interval for affected 

airplanes to continue to operate without 

compromising safety. No change to the 

final rule is necessary in this regard. 

Explanation of Additional Change to 

Proposed AD 

For clarification, we have made minor 

revisions to the wording of Note 2 of 

this final rule. 

Conclusion 

After careful review of the available 

data, including the comments noted 

above, the FAA has determined that air 

safety and the public interest require the 

adoption of the rule with the changes 

previously described. The FAA has 

determined that these changes will 

neither increase the economic burden 

on any operator nor increase the scope 

of the AD. 

Cost Impact 

There are approximately 90 Model 

767–200 and –300 series airplanes of the 

affected design in the worldwide fleet. 

The FAA estimates that 26 airplanes of 

U.S. registry will be affected by this AD, 

that it will take approximately 12 work 

hours (6 work hours per engine) per 

airplane to accomplish the required 

actions, and that the average labor rate 

is $60 per work hour. Required parts 

will cost approximately $12,108 per 

airplane. Based on these figures, the cost 

impact of this AD on U.S. operators is 

estimated to be $333,528, or $12,828 per 

airplane. 

The cost impact figure discussed 

above is 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. 

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 

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:

2002–19–11 Boeing: Amendment 39–12891. 

Docket 2001–NM–268–AD.

Applicability: Model 767–200 and –300 

series airplanes powered by Pratt & Whitney 

JT9D series engines, certificated in any 

category.

Note 1: This AD applies to each airplane 

identified in the preceding applicability

Federal Register / Vol. 67, No. 190 / Tuesday, October 1, 2002 / Rules and Regulations 61481

provision, regardless of whether it has been 

modified, altered, or repaired in the area 

subject to the requirements of this AD. For 

airplanes that have been modified, altered, or 

repaired so that the performance of the 

requirements of this AD is affected, the 

owner/operator must request approval for an 

alternative method of compliance in 

accordance with paragraph (c) of this AD. 

The request should include an assessment of 

the effect of the modification, alteration, or 

repair on the unsafe condition addressed by 

this AD; and, if the unsafe condition has not 

been eliminated, the request should include 

specific proposed actions to address it.

Compliance: Required as indicated, unless 

accomplished previously. 

To prevent failure of the thrust reverser 

deactivation pins, which could result in 

deployment of the thrust reverser in flight 

and consequent reduced controllability of the 

airplane, accomplish the following: 

Replacement 

(a) Within 24 months after the effective 

date of this AD, replace the existing 

deactivation pin, pin bushing in the aft 

cascade mounting ring, and pin insert on 

each thrust reverser half, with new, improved 

components, according to Boeing Alert 

Service Bulletin 767–78A0089, Revision 1, 

dated May 30, 2002.

Note 2: The new, improved insert flange 

and pin bushing does not physically 

preclude use of a deactivation pin having P/

N 315T1604–2 or –5. However, use of 

deactivation pins having P/N 315T1604–2 or 

–5 may not prevent the thrust reversers from 

deploying in the event of a full powered 

deployment. Therefore, thrust reversers 

modified per this AD are required to be 

installed with the new, longer deactivation 

pins having P/N 315T1604–6, as specified in 

the service bulletin.

Credit for Actions Accomplished According 

to Previous Service Bulletin Issue 

(b) Replacements accomplished before the 

effective date of this AD according to Boeing 

Alert Service Bulletin 767–78A0089, dated 

July 19, 2001, are acceptable for compliance 

with the corresponding action required by 

this AD. 

Alternative Methods of Compliance 

(c) An alternative method of compliance or 

adjustment of the compliance time that 

provides an acceptable level of safety may be 

used if approved by the Manager, Seattle 

Aircraft Certification Office (ACO), FAA. 

Operators shall submit their requests through 

an appropriate FAA Principal Maintenance 

Inspector, who may add comments and then 

send it to the Manager, Seattle ACO.

Note 3: Information concerning the 

existence of approved alternative methods of 

compliance with this AD, if any, may be 

obtained from the Seattle ACO.

Special Flight Permits 

(d) Special flight permits may be issued in 

accordance with §§ 21.197 and 21.199 of the 

Federal Aviation Regulations (14 CFR 21.197 

and 21.199) to operate the airplane to a 

location where the requirements of this AD 

can be accomplished. 

Incorporation by Reference 

(e) Unless otherwise specified in this AD, 

the actions shall be done in accordance with 

Boeing Alert Service Bulletin 767–78A0089, 

Revision 1, dated May 30, 2002. 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 Boeing 

Commercial Airplane Group, P.O. Box 3707, 

Seattle, Washington 98124–2207. 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. 

Effective Date 

(f) This amendment becomes effective on 

November 5, 2002.

Issued in Renton, Washington, on 

September 19, 2002. 

Vi L. Lipski, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service.

[FR Doc. 02–24405 Filed 9–30–02; 8:45 am] 

BILLING CODE 4910–13–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. 2002–CE–03–AD; Amendment 

39–12890; AD 2002–19–10] 

RIN 2120–AA64 

Airworthiness Directives; Air Tractor, 

Inc. Models AT–402, AT–402A, AT–

402B, AT–602, AT–802, and AT–802A 

Airplanes

AGENCY: Federal Aviation 

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a 

new airworthiness directive (AD) that 

applies to certain Air Tractor, Inc. (Air 

Tractor) Models AT–402, AT–402A, 

AT–402B, AT–602, AT–802, and AT–

802A airplanes. This AD requires you to 

repetitively inspect the upper longeron 

and upper diagonal tube on the left 

hand side of the aft fuselage structure 

for cracks and contact the manufacturer 

for a repair scheme if cracks are found. 

This AD is the result of reports of 

excessive movement in the empennage 

due to the loss of fuselage torsional 

rigidity. The actions specified by this 

proposed AD are intended to prevent 

failure of the fuselage caused by cracks. 

Such failure could result in loss of 

control of the airplane.

DATES: This AD becomes effective on 

November 15, 2002. 

The Director of the Federal Register 

approved the incorporation by reference 

of certain publications listed in the 

regulations as of November 15, 2002.

ADDRESSES: You may get the service 

information referenced in this AD from 

Air Tractor, Incorporated, P.O. Box 485, 

Olney, Texas 76374. You may view this 

information at the Federal Aviation 

Administration (FAA), Central Region, 

Office of the Regional Counsel, 

Attention: Rules Docket No. 2002-CE–

03-AD, 901 Locust, Room 506, Kansas 

City, Missouri 64106; or at the Office of 

the Federal Register, 800 North Capitol 

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

FOR FURTHER INFORMATION CONTACT:

Andrew D. McAnaul, Aerospace 

Engineer, FAA, Fort Worth Airplane 

Certification Office, 2601 Meacham 

Boulevard, Fort Worth, Texas 76193–

0150; telephone: (817) 222–5156; 

facsimile: (817) 222–5960.

SUPPLEMENTARY INFORMATION: 

Discussion 

What Events Have Caused This AD? 

The FAA received reports of three 

occurrences of cracks found on the left 

hand upper longeron and upper 

diagonal support tubes where they 

intersect on the left hand side of the 

fuselage frame just forward of the 

vertical fin front spar attachment point 

on Air Tractor Model AT–602 airplanes. 

The crack starts at the forward edge of 

the weld where the tubes come together. 

We initially determined that the cracks 

resulted from high vertical tail loads 

during repeated hard turns. The cracks 

were found by the pilot and/or ground 

crew when they noticed excessive 

movement in the empennage due to the 

loss of torsional rigidity. 

Air Tractor started installing extended 

reinforcement gussets on AT–402 and 

AT–802 series airplanes at the factory to 

alleviate the crack condition from 

occurring. The extended reinforcement 

gussets were intended to transfer the