Federal Register / Vol. 66, No. 248 / Thursday, December 27, 2001 / Proposed Rules 66823

AD. For helicopters 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 loss of the tail rotor gearbox

due to attaching bolts of inadequate grip

length and subsequent loss of control of the

helicopter, accomplish the following:

(a) Within 25 hours time-in-service (TIS),

conduct the following inspections:

(1) For each tail rotor gearbox attaching

bolt (bolt):

(i) Determine the part number (P/N).

(ii) If the P/N cannot be determined or if

the bolt is not P/N NAS1304–26, before

further flight, replace the bolt with bolt, P/

N NAS1304–26.

(iii) Torque the bolt to 100–110 in-lbs and

apply a slippage mark.

(2) Remove the tailboom control rod and

determine the number of bolt threads

protruding from each nutplate on the internal

surface of the aft tailboom frame casting, P/

N 369D23503, as shown in Figure 1. At least

one thread must protrude. If more than four

threads protrude, add an additional washer,

P/N AN960D416, under the bolt head.

Torque the bolt to 100–110 in-lbs., and

reapply a slippage mark.

(b) Between 2 and 10 hours TIS after

accomplishing the requirements of paragraph

(a) of this AD, inspect the torque on each bolt

by applying 100 in-lbs. If any bolt movement

occurs, retorque the bolt to 100–110 in-lbs.

and reapply a slippage mark. Reinspect the

torque between 2 and 10 hours TIS thereafter

until no bolt movement occurs.

Note 2: Aerometals Service Bulletin SB–

001, dated August 3, 2000, pertains to the

subject of this AD.

(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, Los

Angeles Aircraft Certification Office

(LAACO), FAA. Operators shall submit their

requests through an FAA Principal

Maintenance Inspector, who may concur or

comment and then send it to the Manager,

LAACO.

Note 3: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the LAACO.

(d) Special flight permits will not be

issued.

Issued in Fort Worth, Texas, on December

14, 2001.

David A. Downey,

Manager, Rotorcraft Directorate, Aircraft

Certification Service.

[FR Doc. 01–31556 Filed 12–26–01; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001–CE–36–AD]

RIN 2120–AA64

Airworthiness Directives; Air Tractor,

Inc. AT–400, AT–500, and AT–800

Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes to

supersede Airworthiness Directive (AD)

2001–10–04 R1, which lowered the safe

life for the wing lower spar cap on

66824 Federal Register / Vol. 66, No. 248 / Thursday, December 27, 2001 / Proposed Rules

certain Air Tractor, Inc. (Air Tractor)

AT–400, AT–500, and AT–800 series

airplanes. AD 2001–10–04 R1 resulted

from numerous reports of cracks in the

3⁄8-inch bolthole of the wing lower spar

cap on the affected airplanes. This

proposed AD would maintain the safe

life and add a requirement for you to

eddy—current inspect the wing lower

spar cap immediately prior to the

replacement/modification in order to

detect and correct any crack in a

bolthole before it extends to the

modified center section of the wing and

repair that crack or replace the wing

section. This proposed AD would also

further reduce the safe life for certain

AT–400 and AT–500 series airplanes

that incorporate or have incorporated

Marburger Enterprises, Inc. winglets.

These winglets are installed in

accordance with Supplemental Type

Certificate (STC) SA00490LA. The

actions specified by this proposed AD

are intended to prevent fatigue cracks

from occurring in the wing lower spar

cap before the originally-established

safe life is reached. Fatigue cracks in the

wing lower spar cap, if not detected and

corrected, could result in the wing

separating from the airplane during

flight.

DATES: The Federal Aviation

Administration (FAA) must receive any

comments on this proposed rule on or

before February 15, 2002 .

ADDRESSES: Submit comments to FAA,

Central Region, Office of the Regional

Counsel, Attention: Rules Docket No.

2001–CE–36–AD, 901 Locust, Room

506, Kansas City, Missouri 64106. You

may view any comments at this location

between 8 a.m. and 4 p.m., Monday

through Friday, except Federal holidays.

You may get service information that

applies to this proposed AD from Air

Tractor, Incorporated, P.O. Box 485,

Olney, Texas 76374; or Marburger

Enterprises, Inc., 1227 Hillcourt,

Williston, North Dakota 58801;

telephone: (800) 893–1420 or (701) 774–

0230; facsimile: (701) 572–2602. You

may also view this information at the

Rules Docket at the address above.

FOR FURTHER INFORMATON CONTACT:

Direct all questions to:

—For the airplanes that do not

incorporate and never have

incorporated Marburger Enterprises,

Inc. winglets: Rob Romero, Aerospace

Engineer, FAA, Fort Worth Airplane

Certification Office, 2601 Meacham

Boulevard, Fort Worth, Texas 76193–

0150; telephone: (817) 222–5102;

facsimile: (817) 222–5960; and

—For certain AT–400 and AT–500

series airplanes that incorporate or

have incorporated Marburger

Enterprises, Inc. winglets: John Cecil,

Aerospace Engineer, Los Angeles

Aircraft Certification Office, FAA,

3960 Paramount Boulevard,

Lakewood, California, 90712;

telephone: (562) 627-5228; facsimile:

(562) 627–5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

How do I comment on this proposed

AD? The FAA invites comments on this

proposed rule. You may submit

whatever written data, views, or

arguments you choose. You need to

include the rule’s docket number and

submit your comments to the address

specified under the caption ADDRESSES.

We will consider all comments received

on or before the closing date. We may

amend this proposed rule in light of

comments received. Factual information

that supports your ideas and suggestions

is extremely helpful in evaluating the

effectiveness of this proposed AD action

and determining whether we need to

take additional rulemaking action.

Are there any specific portions of this

proposed AD I should pay attention to?

The FAA specifically invites comments

on the overall regulatory, economic,

environmental, and energy aspects of

this proposed rule that might suggest a

need to modify the rule. You may view

all comments we receive before and

after the closing date of the rule in the

Rules Docket. We will file a report in

the Rules Docket that summarizes each

contact we have with the public that

concerns the substantive parts of this

proposed AD.

How can I be sure FAA receives my

comment? If you want FAA to

acknowledge the receipt of your

comments, you must include a selfaddressed, stamped postcard. On the

postcard, write ‘‘Comments to Docket

No. 2001–CE–36–AD.’’ We will date

stamp and mail the postcard back to

you.

Discussion

Has FAA taken any action to this

point? Several reports of cracked wing

lower spar caps on Air Tractor AT–400,

AT–500, and AT–800 series airplanes

have caused the manufacturer (Air

Tractor) to recalculate the fatigue life of

the wing lower spar cap on these

airplanes. One report was of an accident

where the wing separated from the

airplane during flight. The cracks are

originating in the outboard 3⁄8-inch

bolthole of the wing lower spar cap.

To address this condition, FAA issued

AD 2001–10–04, Amendment 39–12230

(66 FR 27014, May 16, 2001). This AD

lowers the safe life for the wing lower

spar cap on Air Tractor AT–400, AT–

500, and AT–800 series airplanes. This

AD also allows for inspection, using

eddy current methods, of the wing

lower spar cap for airplanes that are at

or over the lower safe life and parts are

not available. Operation of the airplane

is not allowed if cracks are found and

inspections must be terminated when

parts become available or after

performing three repetitive inspections.

AD 2001–10–04 superseded AD 2000–

14–51, Amendment 39–11837 (65 FR

46567, July 31, 2000). AD 2000–14–51

required inspection of the wing lower

spar cap for cracks on Air Tractor

Models AT–501, AT–502, and AT–502A

airplanes, and modification or

replacement of any cracked wing lower

spar cap.

We inadvertently included certain

AT–800 series airplanes in the

Applicability of AD 2001–10–04. Those

AT–800 series airplanes that are

equipped with the factory-supplied part

number 80540 computerized fire gate

should not be affected by AD 2001–10–

04. Therefore, we revised this AD to

incorporate this change. AD 2001–10–04

R1, Amendment 39–12247, was

published in the Federal Register on

June 4, 2001 (66 FR 29900).

What has happened since AD 2001–

10–04 R1 to initiate this action? In

response to AD 2001–10–04 R1, FAA

received a comment from the National

Transportation Safety Board that

recommended an eddy-current

inspection requirement immediately

prior to the accomplishment of the twopart modification described in Snow

Engineering Service Letters #197, #202,

#203, or #205, all Revised March 26,

2001, as applicable. This is to eliminate

the possibility that a crack that exists in

a bolt hole prior to the modification is

still present after accomplishing the

modification. Prior to the modification,

any crack present will be larger than it

would appear after the outermost bolt

holes are enlarged. This makes the crack

easier to detect and gives the mechanic

an area to concentrate on any postmodification inspections.

Additional analysis also indicates a

higher wing root bending moment that

could lead to reduction of the safe life

for certain AT–400 and AT–500 series

airplanes with a certain configuration.

Airplanes with this configuration either

incorporate or have incorporated

Marburger Enterprises, Inc. winglets on

the wing lower spar cap. These winglets

are installed in accordance with

Supplemental Type Certificate (STC)

SA00490LA. We have developed criteria

for determining what the new safe life

should be for airplanes that either

incorporate or have incorporated these

winglets.

Federal Register / Vol. 66, No. 248 / Thursday, December 27, 2001 / Proposed Rules 66825

The FAA’s Determination and an

Explanation of the Provisions of this

Proposed AD

What has FAA decided?

After examining the circumstances

and reviewing all available information

related to the incidents described above,

we have determined that:

—The unsafe condition referenced in

this document exists or could develop

on other AT–400, AT–500, and AT–

800 series airplanes (specific models

as referenced in the AD) of the same

type design;

—All airplanes should have the eddycurrent inspection accomplished on

the wing lower spar cap immediately

prior to the replacement/modification

in order to detect and correct any

crack in a bolthole before it extends

to the modified center section of the

wing;

—Certain AT–400 and AT–500 series

airplanes that incorporate or have

incorporated Marburger Enterprises,

Inc. winglets should have the safe life

further reduced; and

—AD action should be taken in order to

correct this unsafe condition.

What would this proposed AD

require? This proposed AD would

supersede AD 2001–10–04 R1 with a

new AD that would maintain the safe

life and would add a requirement for

you to eddy-current inspect the wing

lower spar cap immediately prior to the

replacement/modification in order to

detect and correct any crack in a

bolthole before it extends to the

modified center section of the wing and

repair that crack or replace the wing

section. The proposed AD would also

further reduce the safe life for those AT–

400 and AT–500 series airplanes that

incorporate or have incorporated

Marburger Enterprises, Inc. winglets.

Cost Impact

How many airplanes would this

proposed AD impact? We estimate that

this proposed AD affects 1,179 airplanes

in the U.S. registry.

What would be the cost impact of this

proposed AD on owners/operators of the

affected airplanes? We estimate the

following costs to accomplish the

proposed inspection:

Labor cost Parts cost Total cost

per airplane

Total cost on

U.S. operators

2 workhours at $60 per hour = $120 ............................................................................... No parts required for

inspection.

$120 $141,480

We estimate the following costs to

accomplish the proposed replacement/

modification:

Labor cost Parts cost Total cost

Per Airplane

Total cost on

U.S. operators

210 workhours at $60 per hour = $7,200 ............................................................................................ $11,500 $18,700 $22,047,300

What is the difference between the

cost impact of this proposed AD and the

cost impact of AD 2001–10–04 R1? AD

2001–10–04 R1 already established the

safe life for the lower wing spar cap on

the affected airplanes. Therefore, the

replacement/modification is already

required through that AD. The only

difference in the cost impact upon the

public of this proposed AD and AD

2001–10–04 R1 is the cost for the eddycurrent inspection upon replacement

and the further safe life reduction for

those AT–400 and AT–500 series

airplanes that incorporate or have

incorporated Marburger Enterprises, Inc.

winglets.

Regulatory Impact

Would this proposed AD impact

various entities? The regulations

proposed herein 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. Therefore, it is

determined that this proposed rule

would not have federalism implications

under Executive Order 13132.

Would this proposed AD involve a

significant rule or regulatory action? For

the reasons discussed above, I certify

that this proposed 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) if

promulgated, 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 copy of the draft

regulatory evaluation prepared for this

action has been placed in the Rules

Docket. A copy of it may be obtained by

contacting the Rules Docket at the

location provided under the caption

ADDRESSES.

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 Federal Aviation Administration

proposes to amend 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. FAA amends § 39.13 by removing

Airworthiness Directive (AD) 2001–10–

04 R1, Amendment 39–12247 (66 FR

29900, June 4, 2001), and by adding a

new AD to read as follows:

Air Tractor, Inc.: Docket No. 2001-CE–36–

AD; Supersedes AD 2001–10–04 R1,

Amendment 39–12247.

(a) What airplanes are affected by this AD?

Use paragraph (a)(1) of this AD for airplanes

that do not incorporate and never have

incorporated winglets and use paragraph

(a)(2) of this AD for certain AT–400 and AT–

500 series airplanes that incorporate or have

incorporated Marburger Enterprises, Inc.

winglets.

(1) The following presents airplanes

(certificated in any category) that are affected

by this AD, along with the new safe life

(presented in hours time-in-service (TIS)) of

the wing lower spar cap for all airplane

models and serial numbers:

66826 Federal Register / Vol. 66, No. 248 / Thursday, December 27, 2001 / Proposed Rules

Model Serial Nos. Safe life

AT–400 ......................... all serial numbers beginning with 0416 ....................................................................................... 13,300 hours TIS.

AT–401 ......................... 0662 through 0951 ....................................................................................................................... 10,757 hours TIS.

AT–401B ....................... 0952 through 1014 and 1016 though 1020 ................................................................................. 6,948 hours TIS.

AT–401B ....................... 1015 and 1021 through 1124 ....................................................................................................... 7,777 hours TIS

AT–402 ......................... 0694 through 0951 ....................................................................................................................... 7,440 hours TIS.

AT–402A ....................... 0738 through 0951 ....................................................................................................................... 7,440 hours TIS.

AT–402A ....................... 0952 through 1020 ....................................................................................................................... 4,589 hours TIS.

AT–402A ....................... 1021 through 1124 ....................................................................................................................... 5,268 hours TIS.

AT–402B ....................... 0966 through 1020 ....................................................................................................................... 4,589 hours TIS.

AT–402B ....................... 1021 through 1124 ....................................................................................................................... 5,268 hours TIS.

AT–501 ......................... 0002 through 0061 ....................................................................................................................... 4,531 hours TIS.

AT–501 ......................... all serial numbers beginning with 0062 ....................................................................................... 7,693 hours TIS.

AT–502 ......................... 0003 through 0236 ....................................................................................................................... 4,000 hours TIS.

AT–502A ....................... 0158 through 0618 ....................................................................................................................... 3,000 hours TIS.

AT–502B ....................... 0187 through 0618 ....................................................................................................................... 4,000 hours TIS.

AT–503A ....................... all serial numbers beginning with 0067 ....................................................................................... 4,000 hours TIS.

AT–802 ......................... 0001 through 0059 except those equipped with the factory-supplied part number 80540 computerized fire gate.4,132 hours TIS.

AT–802 ......................... 0060 through 0091 except those equipped with the factory-supplied part number 80540 computerized fire gate.4,188 hours TIS.

AT–802 ......................... 0092 through 0101 except those equipped with the factory-supplied part number 80540 computerized fire gate.8,163 hours TIS.

AT–802A ....................... 0003 through 0059 except those equipped with the factory-supplied part number 80540 computerized fire gate.4,969 hours TIS.

AT–802A ....................... 0060 through 0091 except those equipped with the factory-supplied part number 80540 computerized fire gate.4,531 hours TIS.

AT–802A ....................... 0092 through 0101 except those equipped with the factory-supplied part number 80540 computerized fire gate.8,648 hours TIS.

Note 1: Piston powered aircraft that have

been converted to turbine power should use

the limits for corresponding serial number

turbine-powered aircraft.

(2) The following presents airplanes

(certificated in any category) that could

incorporate or could have incorporated

Marburger Enterprises, Inc. winglets. These

winglets are installed in accordance with

Supplemental Type Certificate (STC)

SA00490LA. Use the winglet usage factor in

the table below, the safe life specified in

paragraph (a)(1) of this AD, and the

instructions included in the Appendix to this

AD to determine the new safe life of these

airplanes:

Model Serial Nos. Winglet

usage factor

AT–401 ............................. 0662 through 0951 .................................................................................................................................... 1.6

AT–401B .......................... 0952 through 1014 and 1016 though 1020 .............................................................................................. 1.1

AT–401B .......................... 1015 and 1021 through 1124 ................................................................................................................... 1.1

AT–402 ............................. 0694 through 0951 .................................................................................................................................... 1.6

AT–402A .......................... 0738 through 0951 .................................................................................................................................... 1.6

AT–402A .......................... 0952 through 1020 .................................................................................................................................... 1.1

AT–402A .......................... 1021 through 1124 .................................................................................................................................... 1.1

AT–402B .......................... 0966 through 1020 .................................................................................................................................... 1.1

AT–402B .......................... 1021 through 1124 .................................................................................................................................... 1.1

AT–501 ............................. 0002 through 0061 .................................................................................................................................... 1.6

AT–501 ............................. All serial numbers beginning with 0062 .................................................................................................... 1.6

AT–502 ............................. 0003 through 0236 .................................................................................................................................... 1.6

AT–502A .......................... 0158 through 0618 .................................................................................................................................... 1.6

AT–502B .......................... 0187 through 0618 .................................................................................................................................... 1.2

(b) Who must comply with this AD?

Anyone who wishes to operate any of the

above airplanes must comply with this AD.

(c) What problem does this AD address?

The actions specified by this AD are intended

to prevent fatigue cracks from occurring in

the wing lower spar cap before the originallyestablished safe life is reached. Fatigue

cracks in the wing lower spar cap, if not

detected and corrected, could result in the

wing separating from the airplane during

flight.

(d) What must I do to address this

problem? To address this problem, you must

accomplish the following actions:

Note 2: The 10-hour time-in-service (TIS)

compliance time is maintained from AD

2001–10–04 R1.

Federal Register / Vol. 66, No. 248 / Thursday, December 27, 2001 / Proposed Rules 66827

Action Compliance time Procedures

(1) Modify the applicable aircraft records as follows to show the reduced safe life for the

wing lower spar cap (use the information

from the table in paragraph (a)(1) of this AD

and utilize the information in paragraph (a)(2)

of and the Appendix to this AD, as applicable):

(i) For the affected Models AT–802 and AT–

802A airplanes: update the Owners Manual,

Section 6—Airworthiness Limitations, Life

Limited Parts.

(ii) For all affected airplanes other than the

Models AT–802 and AT–802A airplanes: incorporate the following into the Aircraft Logbook ‘‘In accordance with this AD, the wing

lower spar cap is life limited to ____ (insert

the applicable safe life number from the applicable tables in paragraphs (a)(1) and (a)(2)

of this AD).

(iii) If, as of the time of the logbook all entry requirement of paragraph (d)(1) of this AD,

your airplane is over or within 10 hours of the

safe life, an additional 10 hours TIS is allowed to accomplish the replacement/modification

Accomplish the logbook entry within the next

10 hours TIS after the effective date of this

AD.

The owner/operator holding at least a private

pilot certificate as authorized by section

43.7 of the Federal Aviation Regulations

(14 CFR 43.7) may modify the aircraft

records as specified in paragraphs (d)(1)(i)

and (d)(1(ii) of this AD. Make an entry into

the aircraft records showing compliance

with this portion of the AD in accordance

with section 43.9 of Federal the Aviation

Regulations (14 CFR 43.9). Accomplish the

actual replacement/modification in accordance with Snow Engineering Service Letter

#197, #202, #203, or #205, Revised March

26, 2001, as applicable. The owner/operator may not accomplish the replacement/

modification.

(2) If you have ordered parts from the factory

when it is time to replace the wing lower spar

cap (as required per the logbook safe life reduction in paragraph (d)(1) of this AD), but

the parts are not available, you may eddycurrent inspect the wing lower spar cap.

These inspections are allowed until one of

the following occurs, at which time the replacement/modification (required when the

lower spar cap has reached its safe life) must

be accomplished:

(i) Crack(s) is/are found;

(ii) Parts become available from the manufacturer; or

(iii) Not more than three inspections or 1,200

hours TIS go by: the first inspection would

have to be accomplished upon accumulating

the safe life; the second inspection would

have to be accomplished within 400 hours

TIS after accumulating the safe life; the third

inspection would have to be accomplished

400 hours TIS after the second inspection;

and the replacement/modification would have

to be accomplished within 400 hours TIS

after the third inspection (maximum elapsed

time would be 1,200 hours TIS)

Prior to further flight after ordering the parts

and thereafter at intervals not to exceed

400 hours TIS until one of the criteria paragraphs (d)(2)(i), (d)(2)(ii), and (d)(2)(iii) of

this AD is met.

In accordance with the procedures in Snow

Engineering Service Letter #197, #202,

#203, or #205, all Revised March 26, 2001,

as applicable.

(3) Eddy-current inspect the wing lower spar

cap in order to detect and correct any crack

before it extends to the modified center section of the wing and repair that crack or replace the wing section

Immediately prior to the replacement/modification required when you reach the new safe

life. For airplanes that had this replacement/

modification accomplished in accordance

with either AD 2001–10–04 or AD 2001–

10–04 R1, accomplish this inspection and

any necessary corrective action within the

next 400 hours TIS after the effective date

of this AD, unless already accomplished

(have the mechanic who accomplished the

work mark the logbooks accordingly).

In accordance with the procedures in Snow

Engineering Service Letter #197, #202,

#203, or #205, all Revised March 26, 2001,

as applicable.

(e) Can I comply with this AD in any other

way? (1) You may use an alternative method

of compliance or adjust the compliance time

if:

(i) Your alternative method of compliance

provides an equivalent level of safety; and

(ii) The Manager, Fort Worth or Los

Angeles Airplane Certification Office (ACO),

as applicable, approves your alternative.

Submit your request through an FAA

Principal Maintenance Inspector. The

inspector may add comments before sending

it to the Manager, Fort Worth or Los Angeles

ACO.

(2) Alternative methods of compliance

approved for AD 2001–10–04 and/or AD

2000–14–51 are not considered approved for

this AD.

66828 Federal Register / Vol. 66, No. 248 / Thursday, December 27, 2001 / Proposed Rules

(3) Alternative methods of compliance

approved for AD 2001–10–04 R1 are

considered approved for this AD.

Note 3: This AD applies to each airplane

identified in paragraphs (a)(1) and (a)(2) of

this AD, 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 (e) 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 you have not eliminated the

unsafe condition, specific actions you

propose to address it.

(f) Are there any alternative methods of

compliance already approved or being

considered for this AD? The FAA may

approve, as an alternative method of

compliance, inspection of the wing lower

spar cap. You must submit the request in

accordance with the procedures in paragraph

(e) of this AD and adhere to the following:

(1) If you are over or within 10 hours TIS

of the safe life for the wing lower spar cap

and you have ordered parts and scheduled a

date for the replacement/modification, but

having the replacement/modification done

on this date grounds the airplane, accomplish

the following:

(i) Inspect the wing lower spar cap within

10 hours TIS after approval of the alternative

method of compliance;

(ii) Reinspect thereafter at intervals not to

exceed 400 hours TIS until either cracks are

found, the date of the scheduled

replacement/modification occurs, or 1,200

hours TIS after the initial inspection are

accumulated, whichever occurs first; and

(iii) Accomplish the inspections in

accordance with the procedures in Snow

Engineering Service Letter #197, #202, #203,

or #205, all Revised March 26, 2001, as

applicable.

(2) Submit the following to the Fort Worth

or Los Angeles ACO, as applicable, using the

procedures described in paragraph (e) of this

AD:

(i) The airplane model serial number

designation, and airplane registration number

(N-number);

(ii) The number of hours TIS on the

airplane;

(iii) The scheduled date for the

replacement/modification; and

(iv) The name and location of the

authorized repair shop.

(3) For more information about this issue,

contact:

(i) For the airplanes that do not incorporate

and never have incorporated Marburger

Enterprises, Inc. winglets: Rob Romero,

Aerospace Engineer, FAA, Fort Worth

Airplane Certification Office, 2601 Meacham

Boulevard, Fort Worth, Texas 76193–0150;

telephone: (817) 222–5102; facsimile: (817)

222–5960; and

(ii) For the airplanes that incorporate or

have incorporated winglets: John Cecil,

Aerospace Engineer, Los Angeles Aircraft

Certification Office, FAA, 3960 Paramount

Boulevard, Lakewood, California, 90712;

telephone: (562) 627–5228; facsimile: (562)

627–5210.

(g) What if I need to fly the airplane to

another location to comply with this AD? The

FAA can issue a special flight permit under

sections 21.197 and 21.199 of the Federal

Aviation Regulations (14 CFR 21.197 and

21.199) to operate your airplane to a location

where you can accomplish the requirements

of this AD provided that the following is

adhered to:

(1) Only operate in day visual flight rules

(VFR) only.

(2) Ensure that the hopper is empty.

(3) Limit airspeed to 135 miles per hour

(mph) indicated airspeed (IAS).

(4) Avoid any unnecessary g-forces.

(5) Avoid areas of turbulence.

(6) Plan the flight to follow the most direct

route.

(h) How do I get copies of the documents

referenced in this AD? You may get copies of

the documents referenced in this AD from

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

Olney, Texas 76374; or Marburger

Enterprises, Inc., 1227 Hillcourt, Williston,

North Dakota 58801; telephone: (800) 893–

1420 or (701) 774–0230; facsimile: (701) 572–

2602. You may view these documents at

FAA, Central Region, Office of the Regional

Counsel, 901 Locust, Room 506, Kansas City,

Missouri 64106.

Appendix to Docket No. 2001–CE–36–

AD

The following provides procedures for

determining the safe life for those AT–400

and AT–500 series airplanes that incorporate

or have incorporated Marburger Enterprises,

Inc. winglets. These winglets are installed in

accordance with Supplemental Type

Certificate (STC) SA00490LA.

1. Review your airplane’s logbook to

determine your airplane’s time in service

(TIS) with winglets installed per Marburger

Enterprises STC SA00490LA. This includes

all time spent with the winglets currently

installed and any previous installations

where the winglet was installed and later

removed.

Example: A review of your airplane’s

logbook shows that you have accumulated

350 hours TIS since incorporating the

Marburger STC. Further review of the

airplane’s logbook shows that a previous

owner had installed the STC and later

removed the winglets after accumulating 150

hours TIS. Therefore, your airplane’s TIS

with the winglets installed is 500 hours.

If you determine that the winglet STC has

never been incorporated on your airplane,

then your safe life is presented in paragraph

(a)(1) of this AD. Any future winglet

installation would be subject to a reduced

safe life per these instructions.

2. Determine your airplane’s unmodified

safe life from paragraph (a)(1) of this AD.

Example: Your airplane is a Model AT–

502B, serial number 0292. From paragraph

(a)(1) of this AD, the safe-life of your airplane

is 4,000 hours TIS. All examples from hereon

will be based on the Model AT–502B, serial

number 0292 airplane.

3. Determine the winglet usage factor from

paragraph (a)(2) of this AD.

Example: Again, your airplane is a Model

AT–502B, serial number 0292. From

paragraph (a)(2) of this AD, your winglet

usage factor is 1.2.

4. Adjust the winglet TIS to account for the

winglet usage factor. Multiply the winglet

TIS (result of 1.) by the winglet usage factor

(result of 3.).

Example: Winglet TIS is 500 hours X a

winglet usage factor of 1.2. The adjusted

winglet TIS is 600 hours.

5. Calculate the winglet usage penalty.

Subtract the winglet TIS (result of 1.) from

the adjusted winglet TIS (result of 4.).

Example: Adjusted winglet TIS is 600

hours—the winglet TIS of 500 hours. The

winglet usage penalty is 100 hours TIS.

6. Adjust the safe life of your airplane to

account for winglet usage. Subtract the

winglet usage penalty (result of 5.) result

from the unmodified safe life from paragraph

(a)(1) of this AD (the result of 2.).

Example: The unmodified safe life is 4,000

hours TIS ¥ the 100 hours TIS usage penalty

= 3,900 hours TIS adjusted safe life.

7. If you remove the winglets from your

airplane prior to further flight or no longer

have the winglets installed on your airplane,

the safe life of your airplane is the adjusted

safe life (result of 6.). Enter this number in

paragraph (d)(1) of this AD and the airplane

logbook.

8. If you keep the current winglet

installation on your airplane, you must

further reduce the safe life by dividing the

adjusted safe life (result of 6.) by the winglet

usage factor (result of 3.). Record this result

in your airplane’s logbook.

Example: Adjusted safe life is 3,900 hours

÷ winglet usage factor of 1.2 = 3,250 hours

TIS.

9. If, at anytime in the future, you install

or remove the Marburger winglet STC from

your airplane, you must repeat the

procedures in this Appendix.

Issued in Kansas City, Missouri, on

December 17, 2001.

Michael Gallagher,

Manager, Small Airplane Directorate, Aircraft

Certification Service.

[FR Doc. 01–31555 Filed 12–26–01; 8:45 am]

BILLING CODE 4910–13–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001–CE–47–AD]

RIN 2120–AA64

Airworthiness Directives; Fairchild

Aircraft, Inc. Models SA226 and SA227

Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes to

supersede Airworthiness Directive (AD)