Airworthiness Directives; de Havilland DHC-6 Series Airplanes

[Federal Register Volume 62, Number 88 (Wednesday, May 7, 1997)]
[Rules and Regulations]
[Pages 24810-24812]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-11880]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-CE-45-AD; Amendment 39-10016; AD 97-07-10 R1]
RIN 2120-AA64


Airworthiness Directives; de Havilland DHC-6 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; correction.

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SUMMARY: This document clarifies information in an existing 
airworthiness directive (AD) that applies to de Havilland DHC-6 series 
airplanes that do not have a certain wing strut modification 
(Modification 6/1581) incorporated. That AD currently requires 
inspecting the wing struts for cracks or damage (chafing, etc.), 
replacing wing struts that are found damaged beyond certain limits or 
are found cracked, and incorporating Modification No. 6/1581 to prevent 
future chafing damage. The actions specified in that AD are intended to 
prevent failure of the wing struts, which could result in loss of 
control of the airplane. This document clarifies the requirements of 
the current AD by eliminating all reference to repetitive inspections. 
The AD results from several reports of wing strut damage caused by the 
upper fairing rubbing against the wing strut.

DATES: Effective May 23, 1997.
    The incorporation by reference of certain publications listed in 
the regulations was approved previously by the Director of the Federal 
Register as of May 23, 1997 (62 FR 15373).

FOR FURTHER INFORMATION CONTACT: Jon Hjelm, Aerospace Engineer, FAA, 
New

[[Page 24811]]

York Aircraft Certification Office, 10 Fifth Street, 3rd Floor, Valley 
Stream, New York 11581; telephone (516) 256-7523; facsimile (516) 568-
2716.

SUPPLEMENTARY INFORMATION: On March 26, 1997, the Federal Aviation 
Administration (FAA) issued AD 97-07-10, Amendment 39-9984 (62 FR 
15373, April 1, 1997), which applies to de Havilland DHC-6 series 
airplanes. That AD requires inspecting the wing struts for cracks or 
damage (chafing, etc.), replacing wing struts that are found damaged 
beyond certain limits or are found cracked, and incorporating 
Modification No. 6/1581 to prevent future chafing damage. Modification 
No. 6/1581 consists of installing a preformed nylon shield around the 
area of each wing strut at the upper end closest to the wing. 
Accomplishment of the inspection and modification is required in 
accordance with de Havilland Service Bulletin No. 6/342, dated February 
23, 1976.
    That AD resulted from several reports of wing strut damage caused 
by the upper fairing rubbing against the wing strut on the affected 
airplanes. The actions required by that AD are intended to prevent 
failure of the wing struts, which could result in loss of control of 
the airplane.

Need for the Correction

    Since the issuance of that AD, the FAA noticed that paragraph 
(b)(1) of the AD is unnecessary. This paragraph reads:

    Incorporating Modification No. 6/1581 eliminates the repetitive 
inspection requirement of this AD.

    Repetitive inspections are not required by AD 97-07-10. Leaving 
this paragraph in the AD could lead to confusion among the operators of 
the affected airplanes as to what is the intent of the AD. In addition 
to deleting paragraph (b)(1) of this AD, paragraph (b)(2) will become 
part of paragraph (b).

Correction of Publication

    This document clarifies the requirements of AD 97-07-10, and 
correctly adds the AD as an amendment to section 39.13 of the Federal 
Aviation Regulations (14 CFR 39.13).
    The AD is being reprinted in its entirety for the convenience of 
affected operators. The effective date of the AD remains May 23, 1997.
    Since this action only clarifies a current requirement, it has no 
adverse economic impact and imposes no additional burden on any person. 
Therefore, the FAA has determined that notice and public procedures are 
unnecessary.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Correction

    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing AD 97-07-10, Amendment 39-
9984 (62 FR 15373, April 1, 1997), and by adding a new airworthiness 
directive (AD), to read as follows:

97-07-10 R1  DeHavilland: Amendment 39-10016; Docket No. 93-CE-45-
AD. Revises AD 97-07-10, Amendment 39-9984.

    Applicability: Models DHC-6-1, DHC-6-100, DHC-6-200, and DHC-6-
300 airplanes (all serial numbers), certificated in any category, 
that do not have Modification No. 6/1581 incorporated.

    Note 1: Modification No. 6/1581 consists of installing a 
preformed nylon shield around the area of each wing strut at the 
upper end closest to the wing.

    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 (d) 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 already accomplished.
    To prevent failure of the wing struts, which could result in 
loss of control of the airplane, accomplish the following:
    (a) Within the next 100 hours time-in-service (TIS) after the 
effective date of this AD, inspect the wing struts, part number (P/
N) C6W1005 (or FAA-approved equivalent), for cracks or damage 
(chafing, etc.) in accordance with the ACCOMPLISHMENT INSTRUCTIONS 
section of de Havilland Service Bulletin (SB) No. 6/342, dated 
February 23, 1976.
    (1) If damage is found on a wing strut that exceeds 0.025-inch 
in depth, exceeds a total length of 5 inches, or where any two 
places of damage are separated by less than 10 inches of undamaged 
surface over the length of the strut, prior to further flight, 
replace the wing strut with an airworthy FAA-approved part in 
accordance with the applicable maintenance manual.
    (2) If any crack is found, prior to further flight, replace the 
wing strut with an airworthy FAA-approved part in accordance with 
the applicable maintenance manual.
    (3) If damage is found on a wing strut that exceeds 0.010-inch 
in depth, provided the damage does not exceed 0.025-inch in depth, 
the damage does not exceed a total length of 5 inches, and where any 
two places of damage are separated by a minimum of 10 inches 
undamaged surface over the length of the strut, within 500 hours TIS 
after the inspection specified in paragraph (a) of this AD, replace 
the wing strut with an airworthy FAA-approved part in accordance 
with the applicable maintenance manual.
    (b) Within the next 600 hours TIS after the effective date of 
this AD, incorporate Modification No. 6/1581 in accordance with the 
ACCOMPLISHMENT INSTRUCTIONS section of de Havilland SB No. 6/342, 
dated February 23, 1976. Incorporating Modification No. 6/1581 may 
be accomplished at any time prior to 600 hours TIS after the 
effective date of this AD, at which time it must be incorporated.
    (c) 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.
    (d) An alternative method of compliance or adjustment of the 
compliance times that provides an equivalent level of safety may be 
approved by the Manager, New York Aircraft Certification Office 
(ACO), FAA, 10 Fifth Street, 3rd Floor, 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York ACO.

    (e) The inspections and modification required by this AD shall 
be done in accordance with de Havilland Service Bulletin No. 6/342, 
dated February 23, 1976. This incorporation by reference was 
approved previously by the Director of the Federal Register, in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51, as of May 23, 
1997 (62 FR 15373, April 1, 1997). 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.
    (f) This amendment (39-10016) becomes effective on May 23, 1997.


[[Page 24812]]


    Issued in Kansas City, Missouri, on May 1, 1997.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 97-11880 Filed 5-6-97; 8:45 am]
BILLING CODE 4910-13-U

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