Federal Register / Vol. 60, No. 51 / Thursday, March 16, 1995 / Proposed Rules 14233

eliminates the unsafe condition; or different

actions necessary to address the unsafe

condition described in this AD. Such a

request should include an assessment of the

effect of the changed configuration on the

unsafe condition addressed by this AD. In no

case does the presence of any modification,

alteration, or repair remove any airplane from

the applicability of this AD.

Compliance: Required as indicated, unless

accomplished previously.

To prevent rapid decompression of the

airplane due to cracking and subsequent

failure of certain outflow/safety valves,

accomplish the following:

(a) Within 30 days after January 3, 1995

(the effective date of AD 94–26–01,

amendment 39–9097), revise the Limitations

Section of the FAA-approved Airplane Flight

Manual (AFM) to include the following. This

may be accomplished by inserting a copy of

this AD in the AFM.

‘‘Operation of the airplane at any altitude

above 41,000 feet is prohibited.’’

(b) Within 18 months after the effective

date of this AD, replace the outflow/safety

valves, part numbers 130406–1 and 102850–

5, as identified in Allied Signal Aerospace

Alert Service Bulletin 130406–21–A4011,

Revision 3, dated January 5, 1995, or 102850–

21–A4021, Revision 2, dated October 6, 1994,

as applicable; with serviceable parts in

accordance with the procedures described in

the applicable alert service bulletin.

Accomplishment of this replacement

constitutes terminating action for the

requirement of paragraph (a) of this AD; after

the replacement has been accomplished, the

previously required AFM limitation may be

removed.

(c) As of January 3, 1995 (the effective date

of AD 94–26–01, amendment 39–9097), no

person shall install an outflow/safety valve,

part number 130406–1 or 102850–5, as

identified in Allied Signal Aerospace Alert

Service Bulletin 130406–21–A4011, Revision

3, dated January 5, 1995, or 102850–21–

A4021, Revision 2, dated October 6, 1994, as

applicable; on any airplane unless that valve

is considered to be serviceable in accordance

with the specifications contained in the

Accomplishment Instructions of the

applicable alert service bulletin.

(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, Los

Angeles Aircraft Certification Office (ACO),

FAA, Transport Airplane Directorate.

Operators shall submit their requests through

an appropriate FAA Principal Maintenance

Inspector, who may add comments and then

send it to the Manager, Los Angeles ACO.

Note 2: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Los Angeles ACO.

(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.

Issued in Renton, Washington, on March 9,

1995.

Neil D. Schalekamp,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 95–6322 Filed 3–15–95; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 95–NM–15–AD]

Airworthiness Directives; Boeing

Model B–17E, F, and G 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 all

Boeing Model B–17E, F, and G

airplanes. This proposal would require

inspections to detect cracking and

corrosion of the wing spar chords, bolts

and bolt holes of the spar chords, and

wing terminals; and correction of any

discrepancy found during these

inspections. This proposal is prompted

by reports of cracking and corrosion of

the wing spar. The actions specified by

the proposed AD are intended to

prevent reduced structural integrity of

the wing of the airplane due to the

problems associated with corrosion and

cracking of the wing spar.

DATES: Comments must be received by

April 18, 1995.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–103,

Attention: Rules Docket No. 95–NM–

15–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

Comments may be inspected at this

location between 9:00 a.m. and 3:00

p.m., Monday through Friday, except

Federal holidays.

FOR FURTHER INFORMATION CONTACT:

Philip Forde, Aerospace Engineer,

Airframe Branch, ANM–120S, FAA,

Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind

Avenue, SW., Renton, Washington

98055–4056; telephone (206) 227–2771;

fax (206) 227–1181.

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 shall

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

summarizing 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 Number 95–NM–15–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, Transport Airplane Directorate,

ANM–103, Attention: Rules Docket No.

95–NM–15–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

Recently, during routine inspections

of several Boeing Model B–17 series

airplanes, extensive corrosion and

numerous cracks were found on the

tubular spar chords of the inner wing.

These tubular spar chords mate with the

circular inner wing attach fitting inserts

that are held together by close tolerance

bolts. (There are four such joints on

each wing of the airplane.) Investigation

revealed that moisture trapped in the

inner wing spars caused some of the

bolts in the joint assemblies to seize and

corrode. The FAA has determined that

the wing spar assembly is susceptible to

moisture accumulation, which may

result in internal corrosion and

subsequent cracking in this area. Since

this area is subject to maximum bending

and stress loads, cracking in this area is

particularly critical.

This condition, if not corrected and

detected in a timely manner, could

result in reduced structural integrity of

the wing of the airplane.

Since an unsafe condition has been

identified that is likely to exist or

develop on other products of this same

type design, the proposed AD would

require a dye penetrant inspection to
14234 Federal Register / Vol. 60, No. 51 / Thursday, March 16, 1995 / Proposed Rules

detect cracking and corrosion of the

aluminum wing spar chords; an eddy

current inspection to detect cracking

and corrosion of the bolts and bolt holes

of the spar chords; and correction of any

discrepancies found. The FAA has

determined that the spar-to-wing

terminal joint must be separated,

including removing the wing of the

airplane from the fuselage, to adequately

detect cracking and corrosion of the

bolts, inner wing fittings, and tubular

spar chords. This action would also

require visual and eddy current

inspections to detect cracking and

corrosion of the wing terminals and spar

chords; and repair of any cracking or

corrosion found.

There are approximately 12 airplanes

of the affected design in the worldwide

fleet. The FAA estimates that 10

airplanes of U.S. registry would be

affected by this proposed AD, that it

would take approximately 1,500 work

hours per airplane to accomplish the

proposed actions, and that the average

labor rate is $60 per work hour. Based

on these figures, the total cost impact of

the proposed AD on U.S. operators is

estimated to be $900,000, or $90,000 per

airplane.

The total cost impact figure discussed

above is based on assumptions that no

operator has yet accomplished any of

the proposed requirements of this AD

action, and that no operator would

accomplish those actions in the future if

this AD were not adopted.

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 proposed regulation (1)

is not a ‘‘significant regulatory action’’

under Executive Order 12866; (2) is not

a ‘‘significant rule’’ under the 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 is contained 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 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. App. 1354(a), 1421

and 1423; 49 U.S.C. 106(g); and 14 CFR

11.89.

39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

Boeing: Docket 95–NM–15–AD.

Applicability: All Model B–17E, F, and G

airplanes, certificated in any category.

Note 1: For airplanes on which the

terminal fitting-to-spar chord joint was

separated prior to the effective date of this

AD, and inspection(s) of and/or repair(s) to

the wing terminals-to-spar chords were

accomplished prior to the effective date of

this AD: Applications for an alternative

method of compliance to the requirements of

paragraphs (a) and (b) of this AD should be

submitted to the FAA, in accordance with the

provisions of paragraph (d) of this AD.

Compliance: Required as indicated, unless

accomplished previously.

To prevent reduced structural integrity of

the wing of the airplane, accomplish the

following:

(a) Within 90 days after the effective date

of this AD, accomplish the requirements of

paragraphs (a)(1), (a)(2), and (a)(3) of this AD.

(1) Perform a dye penetrant inspection to

detect cracking of each inboard end of the

eight aluminum wing spar chords, in

accordance with MIL–STD–6866. If any

cracking is detected that is beyond the limits

specified in the acceptance/rejection criteria

contained in sensitivity level Group IV, MIL–

I–25135, prior to further flight, repair in

accordance with a method approved by the

Manager, Seattle Aircraft Certification Office

(ACO), FAA, Transport Airplane Directorate.

Note 2: The part number (P/N) for the

upper wing spar chords is 3–14231–0, and

the P/N for the lower wing spar chords is 3–

14231–1.

(2) Perform a high frequency eddy current

inspection to detect cracking of the bolt holes

of the spar chords, in accordance with a

method approved by the Manager, Seattle

Aircraft Certification Office (ACO), FAA,

Transport Airplane Directorate. The inboardmost bolt on each of the eight wing terminal

fitting-to-wing spar chord tube joints must be

removed to perform this inspection.

Note 3: The following are the P/N’s for the

terminal fitting-to-spar chord joint

assemblies:

Assemblies Assembly

part No.

Left Upper Front Spar Joint

Assembly ............................. 75–4781–0

Right Upper Front Spar Joint

Assembly ............................. 75–4781–1

Left Lower Front Spar Joint

Assembly ............................. 65–4782–512

Right Lower Front Spar Joint

Assembly ............................. 65–4782–513

Left Upper Rear Spar Joint

Assembly ............................. 75–4783–0

Right Upper Rear Spar Joint

Assembly ............................. 75–4783–1

Left Lower Rear Spar Joint

Assembly ............................. 75–4784–0

Right Lower Rear Spar Joint

Assembly ............................. 75–4784–1

Note 4: The following are the P/N’s for the

bolts for the spar chords:

Bolts for Bolt part No.

Upper and Lower Front Spar

Chords.

NAS56A36

Upper Rear Spar Chord ......... NAS56A34

Lower Rear Spar Chord ......... NAS56A40–5

(3) Perform a visual inspection to detect

corrosion of the bolts and replace any

corroded bolt with a new bolt having a P/N

in the NAS 6606 series in accordance with

Army Technical Order Number 01–20EF–2.

Prior to further flight, accomplish the

requirements of paragraphs (a)(3)(i), (a)(3)(ii),

and (a)(3)(iii) of this AD in accordance with

Army Technical Order Number 01–20EF–2.

Note 4: The following are the P/N’s for the

replacement bolts for the spar chords:

Replacement bolts for Replacement

bolt part No.

Upper and Lower Front Spar . NAS 6606–

51

Upper Rear Spar .................... NAS 6606–

47

Lower Rear Spar .................... NAS 6606–

56

(i) Install a washer having P/N MS

20002C6 under the head of the bolt, a selflocking nut having P/N NAS 1804–6, and a

washer having P/N MS 200026 under the nut,

for each replacement bolt.

(ii) Torque any replacement bolt to 95–105

inch-pounds.

(iii) Oversize replacement bolts by 1/16

inch, as necessary.

(b) Within 18 months after the effective

date of this AD, accomplish the requirements

of either paragraph (b)(1) or (b)(2) of this AD.

(1) Perform visual and high frequency eddy

current inspections, that include separating

all eight wing terminal-to-spar chord joints,

to detect cracking and corrosion of the wing

terminals and spar chords, in accordance

with a method approved by the Manager,

Seattle ACO. Or

(2) Perform an equivalent inspection(s) to

that required by paragraph (b)(1) of this AD,
Federal Register / Vol. 60, No. 51 / Thursday, March 16, 1995 / Proposed Rules 14235

that may not include separating the terminal

fitting from the spar chord to detect cracking

and corrosion of all eight wing terminal-tospar chord joints, in accordance with a

method approved by the Manager, Seattle

ACO. To be considered acceptable, the

equivalent inspection(s) must include, at a

minimum, the criteria specified in

paragraphs (b)(2)(i), (b)(2)(ii), and (b)(2)(iii) of

this AD.

(i) The inspection must include removal of

all 64 bolts that join the eight wing terminals

to the eight spar chords; and

(ii) The inspection must adequately detect

cracking of the spar chord, and corrosion

between the terminal fitting and the spar

chord; and

(iii) The inspection must include a visual

inspection to detect corrosion of the

attachment bolts; and a high frequency eddy

current, and boroscope inspection at 10

power magnification, of the bolt holes

common to the spar chord-to-wing terminal

interface.

(c) If any cracking and/or corrosion is

detected during any of the inspections

required by paragraphs (a) and (b) of this AD,

prior to further flight, repair in accordance

with a method approved by the Manager,

Seattle ACO.

(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

ACO. 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 5: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

(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.

Issued in Renton, Washington, on March 9,

1995.

Neil D. Schalekamp,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 95–6321 Filed 3–15–95; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 95–CE–13–AD]

Airworthiness Directives; Fairchild

Aircraft SA226 and SA227 Series

Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes to

adopt a new airworthiness directive

(AD) that would apply to certain

Fairchild Aircraft SA226 and SA227

series airplanes that utilize a direct

current (DC) generator. The proposed

action would require relocating the lefthand (LH) and right-hand (RH) essential

bus current limiters (225 amp) to the

battery bus (main bus tie). A safety

recommendation received by the

Federal Aviation Administration (FAA)

that details potential electrical failure

problems on Fairchild SA226 and

SA227 series airplanes prompted the

proposed action. The actions specified

by the proposed AD are intended to

prevent failure of the LH or RH essential

bus when engine failure results in a

blown generator current limiter, which

could result in loss of airplane electrical

power.

DATES: Comments must be received on

or before June 2, 1995.

ADDRESSES: Submit comments in

triplicate to the FAA, Central Region,

Office of the Assistant Chief Counsel,

Attention: Rules Docket No. 95–CE–13–

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

Fairchild Aircraft, P.O. Box 790490, San

Antonio, Texas 78279–0490; telephone

(210) 824–9421. This information also

may be examined at the Rules Docket at

the address above.

FOR FURTHER INFORMATION CONTACT: Mr.

George R. Hash, Aerospace Engineer,

FAA, Airplane Certification Office, 2601

Meacham Boulevard, Fort Worth, Texas

76193–0150; telephone (817) 222–5134;

facsimile (817) 222–5959.

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. 95–CE–13–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. 95–CE–13–AD, Room

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

Missouri 64106.

Discussion

The FAA has received a safety

recommendation that details potential

electrical failure problems on Fairchild

SA226 and SA227 series airplanes.

Flight simulation revealed that electrical

power loss could occur on the affected

airplanes because of failure of the LH

essential bus. Switching delays between

the left and right side electrical systems

result in left generator motor action,

which could then cause the left side

current limiter to open. This would

result in failure of the left essential bus,

which will result in loss of alternating

current (AC) power to the primary

attitude indicator and the lighting for

the standby attitude indicator.

Failure of either engine will result in

the loss of the essential bus for that side

if the motoring action of the generator

causes the current limiter to open. This

condition, if not detected and corrected,

could result in loss of airplane electrical

power including loss of attitude and

landing gear power.

Fairchild has issued Service Bulletin

(SB) 226–24–034, SB 227–24–015, and

SB CC7–24–002, all Issued: September

29, 1994. These service bulletins

reference a modification that relocates

the RH and LH essential bus current

limiters (225 amp) to the battery bus

(main bus tie). Fairchild Aircraft

Engineering Kit Drawing 27K82376,

‘‘Current Limiter Rebussing Kit,’’

contains the specific procedures for

incorporating this modification on the

affected airplanes.

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 the situation

described above from occurring.