Federal Register / Vol. 62, No. 33 / Wednesday, February 19, 1997 / Proposed Rules 7377

14 CFR Part 39

[Docket No. 96–CE–47–AD]

RIN 2120–AA64

Airworthiness Directives; Air Tractor

Incorporated Models AT–301, AT–302,

AT–400, AT–400A, AT–401, AT–402,

AT–501, and AT–502 Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes to

supersede AD 95–20–06, which

currently requires inspecting the front

spar attachment lugs and the rear spar

for fatigue cracks and modifying the

vertical fin if cracks are found. If no

cracks are found, continue repetitively

inspecting the area until cracks are

found; and then incorporate the

modification as a terminating action.

The proposed action would retain the

actions required in AD 95–20–06 for all

Air Tractor models that have a 3⁄16-inch

fin front spar fitting. Air Tractor models

that are fitted with a 1⁄4-inch fin front

spar fitting would not be required to

accomplish this action. This action is

prompted by two incident reports

involving the failure of the front and

rear spar attachment of the vertical fin.

The actions specified by this AD are

intended to prevent in-flight vertical fin

structural failure of the front spar

attachments and eventually the rear spar

attachment, which, if not detected and

corrected, could result in loss of

directional control and loss of control of

the airplane.

DATES: Comments must be received on

or before April 21, 1997.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Central Region,

Office of the Assistant Chief Counsel,

Attention: Rules Docket No. 96–CE–47–

AD, Room 1558, 601 E. 12th Street,

Kansas City, Missouri 64106. Comments

may be inspected at this location

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

through Friday, holidays excepted.

Service information that applies to the

proposed AD may be obtained from Air

Tractor Incorporated, P. O. Box 485,

Olney, Texas 76374. This information

also may be examined at the Rules

Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Bob

May, Aerospace Engineer, FAA,

Airplane Certification Office, 2601

Meacham Boulevard, Fort Worth, Texas

76193–0150; telephone (817) 222–5156;

facsimile (817) 222–5960.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to

participate in the making of the

proposed rule by submitting such

written data, views, or arguments as

they may desire. Communications

should identify the Rules Docket

number and be submitted in triplicate to

the address specified above. All

communications received on or before

the closing date for comments, specified

above, will be considered before taking

action on the proposed rule. The

proposals contained in this notice may

be changed in light of the comments

received.

Comments are specifically invited on

the overall regulatory, economic,

environmental, and energy aspects of

the proposed rule. All comments

submitted will be available, both before

and after the closing date for comments,

in the Rules Docket for examination by

interested persons. A report that

summarizes each FAA-public contact

concerned with the substance of this

proposal will be filed in the Rules

Docket.

Commenters wishing the FAA to

acknowledge receipt of their comments

submitted in response to this notice

must submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket No. 96–CE–47–AD.’’ The

postcard will be date stamped and

returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this

NPRM by submitting a request to the

FAA, Central Region, Office of the

Assistant Chief Counsel, Attention:

Rules Docket No. 96–CE–47–AD, Room

1558, 601 E. 12th Street, Kansas City,

Missouri 64106.

Discussion

It has been brought to the attention of

the FAA that AD 95–20–06, which is

applicable to Air Tractor Models AT–

301, AT–302, AT–400, AT–400A, AT–

401, AT–402, AT–501, and AT–502

airplanes, should not have included

models that are fitted with 1⁄4-inch thick

fin front spar attach fittings. The current

AD requires inspecting for cracks on all

of the models referenced above,

regardless of whether they have 1⁄4-inch

or 3⁄16-inch thick front spar attachment

fitting, and if no cracks are found,

repetitively inspecting at different time

intervals. The time interval would

depend on the thickness of the fin front

spar attach fitting on the airplane. If

cracks are found, the current AD

requires modifying the front spar

attachment. Since publication of AD 95–

20–06, further investigation has

revealed that the only Air Tractor

models developing cracks are the

models fitted with a 3⁄16-inch thick front

spar attachment fitting. For this reason,

the FAA is proposing to supersede the

current AD to change the instructions of

the AD.

Relevant Service Information

Air Tractor has issued a revised

Service Letter (SL) No. 138, Revised

August 7, 1996, which specifies

procedures for inspecting, repetitively

inspecting, and modifying the Air

Tractor Models that have the 3/16-inch

thick front spar attach fitting.

FAA’s Determination

After examining the circumstances

and reviewing all available information

related to the incidents described above,

the FAA has determined that AD action

should be taken to prevent in-flight

vertical fin structural failure of the front

spar attachments and eventually the rear

spar attachment, which, if not detected

and corrected, could result in loss of

directional control and loss of control of

the airplane.

Explanation of the Provisions of the

Proposed AD

Since an unsafe condition has been

identified that is likely to exist or

develop in other Air Tractor

Incorporated Models AT–301, AT–302,

AT–400, AT–400A, AT–401, AT–402,

AT–501, and AT–502 airplanes of the

same type design that are fitted with 3/

16-inch thick front spar attachment

fittings, the proposed AD would

supersede AD 95–20–06 with a new AD

that would require inspecting the fin

front spar attach fitting lugs of models

that have 3/16-inch thick fin front spar

attach fittings for cracks and if cracks

are found, prior to further flight,

modifying the front spar attachment

lugs. If no cracks are found, the

proposed AD would require repetitively

inspecting the front spar attachment

lugs until cracks are found.

Accomplishing the modification would

terminate the repetitive inspections.

Cost Impact

The FAA estimates that 24 airplanes

in the U.S. registry would be affected by

the proposed AD, that it would take

approximately 16 workhours per

airplane to accomplish the proposed

action, and that the average labor rate is

approximately $60 an hour. Parts cost

approximately $10 per airplane. Based

on these figures, the total cost impact of

the proposed AD on U.S. operators is

estimated to be $970 per airplane and
7378 Federal Register / Vol. 62, No. 33 / Wednesday, February 19, 1997 / Proposed Rules

$23,280 for the U.S. fleet. The FAA has

no way of determining how many

owners/operators of these affected

airplanes have accomplished this

action.

Regulatory Impact

The regulations proposed herein

would not have substantial direct effects

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,

in accordance with Executive Order

12612, it is determined that this

proposal would not have sufficient

federalism implications to warrant the

preparation of a Federalism Assessment.

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) 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, pursuant to the

authority delegated to me by the

Administrator, the Federal Aviation

Administration proposes to amend 14

CFR part 39 of the Federal Aviation

Regulations as follows:

PART 39—AIRWORTHINESS

DIRECTIVES

1. The authority citation for part 39

continues to read as follows:

Authority: 49 USC 106(g), 40113, 44701.

§ 39.13 [Amended]

2. Section 39.13 is amended by

removing Airworthiness Directive (AD)

95–20–06, Amendment 39–9384, and by

adding a new AD to read as follows:

Air Tractor Incorporated: Docket No. 96–

CE–47–′AD; Supersedes AD 95–20–06,

Amendment 39–9384.

Applicability: The following airplane

models and serial numbers that have not

accomplished the modification in Snow

Engineering Company Report No. 138,

dated July 29, 1995, which is referenced

in superseded AD 95–20–06, certificated

in any category:

Note 1: The modification in Snow

Engineering Company Report No. 138, dated

July 29, 1995 and AD 95–20–06 required the

airplanes to replace 3/16-inch thick fin front

spar attach fittings with 1/4-inch thick fin

front spar attach fittings.

Models Serial Nos.

AT–301 and

AT–401.

301–0261 through 301–0736,

and 401–0662 through

401–0736 that have been

converted to turbine powerplants and equipped with

the all metal rudder, part

number (P/N) 30456–1.

AT–302 ........ All aircraft equipped with the

all metal rudder, P/N

30456–1.

AT–400 and

AT–400A.

All aircraft equipped with the

all metal rudder, P/N

30456–1.

AT–402 ........ 402–0694 and 402–0695

through 402–0736.

AT–501 ........ 501–0002 through 501–0030

that have been converted to

turbine powerplants and

equipped with the all metal

rudder, P/N 30456–1.

AT–502 ........ 502–0002 through 502–0030.

Note 2: This AD applies to each airplane

identified in the preceding applicability

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 (f) 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 initially within the

next 25 hours time-in-service (TIS) after the

effective date of this AD, unless already

accomplished, and thereafter as indicated in

the body of this AD.

To prevent in-flight vertical fin structural

failure of the front spar attachments and

eventually the rear spar attachment, which,

if not detected and corrected, could result in

loss of directional control and loss of control

of the airplane, accomplish the following:

(a) Inspect the fin front spar attachment

fittings for fatigue cracks in accordance with

the INSTRUCTIONS section of the Snow

Engineering Report (SER) number (No.) 138,

Revised August 7, 1996.

(b) If no cracks are found during the initial

inspection, repeat the inspection required by

paragraph (a) of this AD at intervals not to

exceed 25 hours TIS thereafter in accordance

with the INSTRUCTIONS section of the SER

No. 138, Revised August 7, 1996.

(c) If cracks are found during any

inspections required by this AD, prior to

further flight, modify the fin front spar

attachment fittings in accordance with the

INSTRUCTIONS section of the SER No. 138,

Revised August 7, 1996.

(d) Incorporating the modification

specified in paragraph (c) of this AD is

considered terminating action for the

repetitive inspection requirements of this

AD.

(e) Special flight permits may be issued in

accordance with 14 CFR 21.197 and 21.199

to operate the airplane to a location where

the requirements of this AD can be

accomplished.

(f) An alternative method of compliance or

adjustment of the initial or repetitive

compliance times that provides an equivalent

level of safety may be approved by the

Manager, Fort Worth Airplane Certification

Office, 2601 Meacham Boulevard, Fort

Worth, Texas 76193–0150. The request shall

be forwarded through an appropriate FAA

Maintenance Inspector, who may add

comments and then send it to the Manager,

Fort Worth Airplane Certification Office.

Alternative methods of compliance approved

in accordance with AD 95–20–06 are

considered approved as alternative methods

of compliance for this AD.

Note 3: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Fort Worth Aircraft

Certification Office.

(g) All persons affected by this directive

may obtain copies of the document referred

to herein upon request to Air Tractor

Incorporated, P. O. Box 485, Olney, Texas

76374; or may examine this document at the

FAA, Central Region, Office of the Assistant

Chief Counsel, Room 1558, 601 E. 12th

Street, Kansas City, Missouri 64106.

(h) This amendment supersedes AD 95–

20–06, Amendment 39–9384. Issued in

Kansas City, Missouri, on February 10, 1997.

Henry A. Armstrong,

Acting Manager, Small Airplane Directorate,

Aircraft Certification Service.

[FR Doc. 97–3958 Filed 2–18–97; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 96–NM–144–AD]

RIN 2120–AA64

Airworthiness Directives;

Construcciones Aeronauticas, S.A.

(CASA) Model CN–235 Series

Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes the

adoption of a new airworthiness

directive (AD) that is applicable to

certain CASA Model CN–235 series

airplanes. This proposal would require

disabling the brake control valve of the