[Federal Register Volume 60, Number 219 (Tuesday, November 14, 1995)]
[Proposed Rules]
[Pages 57201-57203]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-27984]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-CE-47-AD]


Airworthiness Directives; de Havilland Model DHC-3 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to supersede Airworthiness Directive 
(AD) 90-12-08, which currently requires the following on de Havilland 
Model DHC-3 airplanes: repetitively inspecting (using dye penetrant 
methods) the tailplane main rib forward flanges and the main rib 
forward lower flanges at the tailplane front attachment fitting for 
cracks and repairing any cracked flange. The proposed action would 
retain the repetitive inspections currently required by AD 90-12-08, 
and would allow the provision of incorporating a certain modification 
as terminating action for these repetitive inspections. The proposed 
action is prompted by the Federal Aviation Administration's 
determination that installing new angles and plates on the tailplane 
root ribs on de Havilland Model DHC-3 airplanes provides an equivalent 
level of safety to the repetitive inspections required by AD 90-12-08. 
The actions specified by the proposed AD are intended to prevent 
failure of the tailplane structure caused by cracked tailplane main rib 
forward flanges or main rib forward lower flanges at the tailplane 
front attachment fitting, which, if not detected and corrected, could 
result in loss of control of the airplane.

DATES: Comments must be received on or before January 12, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 95-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 Bombardier Inc., (the parent company of de Havilland) Bombardier 
Regional Aircraft Division, Garrett Boulevard, Downsview, Ontario, 
Canada M3K 1Y5; telephone (416) 633-7310. This information also may be 
examined at the Rules Docket at the address above.


[[Page 57202]]

FOR FURTHER INFORMATION CONTACT: Mr. Jeff Casale, Aerospace Engineer, 
FAA, New York Aircraft Certification Office, 10 5th St., 3rd Floor, 
Valley Stream, New York 11581; telephone (516) 256-7521; facsimile 
(516) 568-2716.

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-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. 95-CE-47-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.

Discussion

    AD 90-12-08, Amendment 39-6622 (55 FR 1450, January 16, 1990), 
currently requires the following on de Havilland Model DHC-3 airplanes: 
repetitively inspecting (using dye penetrant methods) the tailplane 
main rib forward flanges and the main rib forward lower flanges at the 
tailplane front attachment fitting for cracks and repairing any cracked 
flange. Accomplishment of the actions required by AD 90-12-08 is in 
accordance with de Havilland Service Bulletin (SB) No. 3/46, Revision 
B, dated December 1, 1989.
    Since issuance of AD 90-12-08, de Havilland has developed tailplane 
root rib angles and plates of improved design (Modification 3/935). 
When incorporated, Modification 3/935 eliminates the need for the 
repetitive inspections required by AD 90-12-08.
    Bombardier, Inc. (the parent company of de Havilland) has issued de 
Havilland SB No. 3/50, Revision A, dated February 17, 1995, which 
specifies procedures for incorporating Modification 3/935 on de 
Havilland Model DHC-3 airplanes.
    Transport Canada, which is the airworthiness authority for Canada, 
classified this service bulletin as mandatory and revised Transport 
Canada AD CF-89-20 to the R1 level, dated February 22, 1995, in order 
to assure the continued airworthiness of these airplanes in Canada.
    This airplane model is manufactured in Canada and is type 
certificated for operation in the United States under the provisions of 
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and 
the applicable bilateral airworthiness agreement between Canada and the 
United States. Pursuant to this bilateral airworthiness agreement, 
Transport Canada has kept the FAA informed of the situation described 
above.
    After examining the findings of Transport Canada and reviewing all 
available information related to the incidents described above 
including the referenced service information, the FAA has determined 
that (1) incorporating Modification 3/935 provides an equivalent level 
of safety to the repetitive inspections required by AD 90-12-08; and 
(2) AD action should be taken to prevent failure of the tailplane 
structure caused by cracked tailplane main rib forward flanges or main 
rib forward lower flanges at the tailplane front attachment fitting, 
which, if not detected and corrected, could result in loss of control 
of the airplane.
    Since an unsafe condition has been identified that is likely to 
exist or develop in other de Havilland Model DHC-3 airplanes of the 
same type design that do not have Modification 3/935 incorporated, the 
proposed AD would supersede AD 90-12-08 with a new AD that would (1) 
retain the requirement of repetitively inspecting the tailplane main 
rib forward flanges and the main rib forward lower flanges at the 
tailplane front attachment fitting for cracks and repairing any cracked 
flange; and (2) allowing for the provision of incorporating 
Modification 3/935 as terminating action for the repetitive 
inspections. Accomplishment of the proposed inspections would be in 
accordance with de Havilland SB No. 3/46, Revision B, dated December 1, 
1989. Accomplishment of the proposed modification would be in 
accordance with de Havilland SB No. 3/50, Revision A, dated February 
17, 1995.
    The FAA estimates that 49 airplanes in the U.S. registry would be 
affected by the proposed AD, that it would take approximately 35 
workhours per airplane to accomplish the proposed inspection and that 
the average labor rate is approximately $60 an hour. Based on these 
figures, the total cost impact of the proposed AD on U.S. operators is 
estimated to be $102,900 or $2,100 per airplane. This figure represents 
the cost of the initial inspection, and does not reflect the costs for 
repetitive inspections or possible repairs. The FAA has no way of 
determining how many tailplane main rib forward or main rib forward 
lower flanges may need repaired or how many repetitive inspections each 
owner/operator of the affected airplanes would incur over the life of 
the airplane.
    The FAA has issued alternative methods of compliance (AMOC) to the 
repetitive inspection requirement of AD 90-12-08 for owners/operators 
of three de Havilland Model DHC-3 airplanes. These AMOC's consist of 
the incorporation of a certain design modification in the tailplane 
root rib area of the affected airplanes. These AMOC's would remain in 
effect for the proposed AD, which would eliminate the inspection costs 
for these three airplanes. With this in mind, the cost of the proposed 
AD would be reduced by $6,300 from $102,900 to $96,600.
    The compliance time of the proposed AD is in calendar time instead 
of hours time-in-service (TIS). In developing the compliance time of AD 
90-12-08, the FAA utilized calendar time because it was unknown whether 
the rib flange cracking was a result of in-flight loads (flight hours) 
or loads associated with ground gusts. With this in mind, airplanes 
with lower usage may experience a cracked rib flange before an airplane 
with higher usage. For this reason, calendar time rather than flight 
hours was judged to be an appropriate inspection basis. This situation 
still exists and in order to maintain the repetitive inspection 
continuity between AD 90-12-08 and the proposed AD, a compliance based 
on calendar time is proposed.
    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 

[[Page 57203]]
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 U.S.C. 106(g); 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Airworthiness Directive 
(AD) 90-12-08, Amendment 39-6622 (55 FR 1450, January 16, 1990), and by 
adding the following new AD:

De Havilland: Docket No. 95-CE-47-AD; Supersedes AD 90-12-08, 
Amendment 39-6622.
    Applicability: Model DHC-3 Airplanes (all serial numbers), 
certificated in any category, that do not have Modification 3/935 
incorporated in accordance with de Havilland Service Bulletin (SB) 
number (No.) 3/50, Revision A, dated February 17, 1995.

    Note 1: 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 (e) 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: Within the next 3 calendar months after the 
effective date of this AD, unless already accomplished (compliance 
with AD 90-12-08), and thereafter at intervals not to exceed 24 
calendar months.
    To prevent failure of the tailplane structure caused by cracked 
tailplane main rib forward flanges or main rib forward lower flanges 
at the tailplane front attachment fitting, which, if not detected 
and corrected, could result in loss of control of the airplane, 
accomplish the following:
    (a) Inspect, using dye penetrant methods, the tailplane main rib 
forward flanges and the main rib forward lower flanges at the 
tailplane front attachment fitting in accordance with the 
ACCOMPLISHMENT INSTRUCTIONS section of de Havilland SB No. 3/46, 
Revision B, dated December 1, 1989.
    (b) Prior to further flight, repair any tailplane main rib 
forward flange or main rib forward lower flange found cracked during 
any inspection required by this AD. Accomplish this repair in 
accordance with the ACCOMPLISHMENT INSTRUCTIONS section of de 
Havilland SB No. 3/46, Revision B, dated December 1, 1989.
    (c) Installing tailplane root rib angles and plates of improved 
design (Modification 3/935) in accordance with de Havilland SB 3/50, 
Revision A, dated February 17, 1995, terminates the repetitive 
inspection requirement of this AD. Modification 3/935 may be 
incorporated at any time provided that any tailplane main rib 
forward flange or main rib forward lower flange found cracked during 
any inspection required by this AD is repaired.
    (d) 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.
    (e) 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), 10 5th St., 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York ACO.

    (f) Alternative methods of compliance approved in accordance 
with AD 90-12-08 (superseded by this action) are considered approved 
as alternative methods of compliance with this AD.
    (g) All persons affected by this directive may obtain copies of 
the document referred to herein upon request to Bombardier Inc., 
Bombardier Regional Aircraft Division, Garrett Boulevard, Downsview, 
Ontario, Canada M3K 1Y5; telephone (416) 633-7310; 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 90-12-08, Amendment 39-6622.

    Issued in Kansas City, Missouri, on November 6, 1996.
Henry A. Armstrong,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-27984 Filed 11-13-95; 8:45 am]
BILLING CODE 4910-13-U