Airworthiness Directives; Beech Aircraft Corporation Models 34C, T-34C, and T-34C-1 Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-CE-07-AD]

Airworthiness Directives; Beech Aircraft Corporation Models 34C,

T-34C, and T-34C-1 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 Beech Aircraft Corporation (Beech)

Models 34C, T-34C, and T-34C-1 airplanes. The proposed action would

require replacing the eight wing attachment steel bolts and hardware

with Inconel bolts and hardware. A report of the right lower aft wing

attachment nut assembly separating in two pieces on a Model T-34C-1

airplane prompted the proposed action. The actions specified by the

proposed AD are intended to prevent the wing from separating from the

fuselage because of failure of this assembly.

DATES: Comments must be received on or before December 30, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Central Region, Office of the Assistant Chief

Counsel, Attention: Rules Docket No. 94-CE-07-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 the Beech Aircraft Corporation, P.O. Box 85, Wichita, Kansas

67201-0085. This information also may be examined at the Rules Docket

at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. Larry Engler, Aerospace Engineer,

Wichita Aircraft Certification Office, FAA, 1801 Airport Road, Mid-

Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4122;

facsimile (316) 946-4407.

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. 94-CE-07-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. 94-CE-07-AD, Room 1558, 601 E. 12th Street,

Kansas City, Missouri 64106.

Discussion

The FAA has received a report of the right lower aft wing

attachment nut assembly separating in two pieces on a Beech Model T-

34C-1 airplane. Laboratory investigation of the nut assembly revealed

that stress corrosion caused the failure. If the separated assembly is

not detected and corrected, and is operated in that condition, the wing

could separate from the fuselage.

Beech has issued Service Bulletin (SB) No. 2487, dated August 1993,

which specifies procedures for installing Inconel wing attachment

hardware on Models 34C, T-34C, and T-34C-1 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 wing from

separating from the fuselage because of failure of this assembly.

Since an unsafe condition has been identified that is likely to

exist or develop in other Beech 34C, T-34C, and T-34C-1 airplanes of

the same type design, the proposed AD would require replacing the eight

wing attachment steel bolts and hardware with Inconel bolts and

hardware. The proposed actions would be accomplished in accordance with

Beech SB No. 2487, dated August 1993.

The compliance time for the proposed AD is presented in calendar

time instead of hours time-in- service (TIS). The FAA has determined

that a calendar time for compliance is the most desirable method

because the unsafe condition described by the proposed AD is caused by

stress corrosion. Stress corrosion initiates as a result of airplane

operation, but can continue to develop regardless of whether the

airplane is in service or in storage. Therefore, to ensure that the

above-referenced condition is detected and corrected on all airplanes

within a reasonable period of time without inadvertently grounding any

airplanes, a compliance schedule based upon calendar time instead of

hours TIS is proposed.

The FAA estimates that 494 airplanes in the U.S. registry would be

affected by the proposed AD, that it would take approximately 8

workhours per airplane to accomplish the proposed action, and that the

average labor rate is approximately $55 an hour. Parts cost

approximately $800 per airplane. Based on these figures, the total cost

impact of the proposed AD on U.S. operators is estimated to be

$612,560. This figure is based on the assumption that no affected

airplane owners/operator has accomplished the proposed replacement.

The Beech Aircraft Company has informed the FAA that 89 wing

attachment assembly kits have been sold. Assuming that each of these

kits is installed on an affected airplane, this would reduce the cost

impact of the proposed AD upon U.S. operators of the affected airplanes

by $110,360 from $612,560 to $502,200.

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

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.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding a new AD to read as follows:

Beech Aircraft Corporation: Docket No. 94-CE-07-AD.

Applicability: The following model and serial number airplanes,

certificated in any category, that have steel wing attachment

assembly bolts and hardware:

------------------------------------------------------------------------

Model Serial Nos.

------------------------------------------------------------------------

34C........... GP-1 through GP-50.

T-34C......... GL-2 through GL-353.

T-34C-1....... GM-1 through GM-71 and GM-78 through GM-98.

------------------------------------------------------------------------

Compliance: Within whichever of the following occurs later,

unless already accomplished:

Four years after airplane manufacture;

Four years after installing a new wing attachment

assembly; or

Within the next 30 calendar days after the effective

date of this AD.

To prevent the wing from separating from the fuselage because of

failure of the wing attachment nut assembly, accomplish the

following:

(a) Replace all eight steel wing attach bolts and hardware with

Inconel bolts and hardware in accordance with the ACCOMPLISHMENT

INSTRUCTIONS section in Beech Service Bulletin No. 2487, dated

August 1993.

Note 1: Replacing all eight steel wing attach bolts and hardware

with Inconel bolts and hardware as required by this AD eliminates

the repetitive inspection requirements of AD 85-22-05, Amendment 39-

5146, for the affected airplanes.

(b) Special flight permits may be issued in accordance with

Secs. 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.

(c) An alternative method of compliance or adjustment of the

compliance time that provides an equivalent level of safety may be

approved by the Manager, Wichita Aircraft Certification Office

(ACO), 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita,

Kansas 67209. The request shall be forwarded through an appropriate

FAA Maintenance Inspector, who may add comments and then send it to

the Manager, Wichita ACO.

Note 2: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Wichita ACO.

(d) All persons affected by this directive may obtain copies of

the document referred to herein upon request to the Beech Aircraft

Corporation, P.O. Box 85, Wichita, Kansas 67201-0085; 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.

Issued in Kansas City, Missouri, on October 19, 1994.

John R. Colomy,

Acting Manager, Small Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-26372 Filed 10-24-94; 8:45 am]

BILLING CODE 4910-13-U