Airworthiness Directives: de Havilland DHC-6 Series Airplanes

SUMMARY: This amendment adopts a new airworthiness directive (AD) that

applies to de Havilland DHC-6 series airplanes. This action requires

repetitively inspecting the horizontal stabilizer center hinge bracket

for cracks, and replacing any cracked center hinge bracket. Several

reports of cracks in the horizontal stabilizer center hinge bracket

flange on the affected airplanes prompted this action. The actions

specified by this AD are intended to prevent separation of the elevator

control support from the airplane as a result of a cracked horizontal

stabilizer center hinge bracket, which could result in reduced

controllability of the airplane.

DATES: Effective August 31, 1994.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of August 31, 1994.

ADDRESSES: Service information that applies to this AD may be obtained

from de Havilland, Inc., 123 Garratt Boulevard, Downsview, Ontario,

Canada, M3K 1Y5. This information may also be examined at the Federal

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

Chief Counsel, Room 1558, 601 E. 12th Street, 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: Jon Hjelm, Aerospace Engineer, FAA,

New York Aircraft Certification Office, 181 South Franklin Avenue, Room

202, Valley Stream, New York 11581; telephone (516) 791-6220; facsimile

(516) 791-9024.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) to include an AD that would apply

to certain de Havilland DHC-6 series airplanes was published in the

Federal Register on February 17, 1994 (59 FR 7913). The action proposed

to require repetitively inspecting the horizontal stabilizer center

hinge bracket for cracks, and replacing any cracked center hinge

bracket. The proposed action would be accomplished in accordance with

the ACCOMPLISHMENT INSTRUCTIONS section of de Havilland Service

Bulletin 6/512, dated October 25, 1991.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. No comments were received on the

proposed rule or the FAA's determination of the cost to the public.

After careful review of all available information, the FAA has

determined that air safety and the public interest require the adoption

of the rule as proposed except for minor editorial corrections. The FAA

has determined that these minor corrections will not change the meaning

of the AD nor add any additional burden upon the public than was

already proposed.

The FAA estimates that 169 airplanes in the U.S. registry will be

affected by this AD, that it will take approximately 1 workhour per

airplane to accomplish the required action, and that the average labor

rate is approximately $55 an hour. Based on these figures, the total

cost impact of the AD on U.S. operators is estimated to be $9,295. This

figure only includes the cost for the initial inspection and does not

include replacement costs if a center hinge bracket is found cracked

nor does it include repetitive inspection costs. The FAA has no way to

determine how many center hinge brackets may be cracked or how many

repetitive inspections each owner/operator may incur.

The regulations adopted herein will 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 final

rule does 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) 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 final 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, 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. 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 airworthiness directive

to read as follows:

94-14-22 de Havilland: Amendment 39-8971; Docket No. 93-CE-52-AD.

Applicability: Models DHC-6-1, DHC-6-100, DHC-6-200, and DHC-6-

300 airplanes (all serial numbers), certificated in any category.

Compliance: Required within the next 250 hours time-in-service

(TIS), unless already accomplished, and thereafter at intervals not

to exceed 1,200 hours TIS.

To prevent separation of the elevator control support from the

airplane as a result of a cracked horizontal stabilizer center hinge

bracket, which could result in reduced controllability of the

airplane, accomplish the following:

(a) Inspect the horizontal stabilizer center hinge bracket for

cracks in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of

de Havilland Service Bulletin 6/512, dated October 25, 1991, except

that where dye penetrant inspections are specified, accomplish

visual inspections with a strong light source and 10X magnifying

glass. If any cracks are found, prior to further flight, replace the

center hinge bracket in accordance with the referenced service

bulletin.

Note 1: The repetitive inspection requirement of this AD still

applies if the center hinge bracket is replaced.

(b) 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.

(c) 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, New York Aircraft

Certification Office (ACO), FAA, 181 South Franklin Avenue, Room

202, Valley Stream, New York 11581. The request shall be forwarded

through an appropriate FAA Maintenance Inspector, who may add

comments and then send it to the Manager, New York ACO.

Note 2: Information concerning the existence of approved

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

obtained from the New York ACO.

(d) The inspections required by this AD shall be done in

accordance with de Havilland Service Bulletin 6/512, dated October

25, 1991. 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 de Havilland, Inc.,

123 Garratt Boulevard, Downsview, Ontario M3K 1Y5 Canada. Copies may

be inspected at the FAA, Central Region, Office of the Assistant

Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri,

or at the Office of the Federal Register, 800 North Capitol Street,

NW., suite 700, Washington, DC.

(e) This amendment (39-8971) becomes effective on August 31,

1994.

Issued in Kansas City, Missouri, on July 1, 1994.

John R. Colomy,

Acting Manager, Small Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-16536 Filed 7-7-94; 8:45 am]

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