[Federal Register Volume 64, Number 121 (Thursday, June 24, 1999)]
[Rules and Regulations]
[Pages 33747-33751]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 99-15925]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-SW-23-AD; Amendment 39-11207; AD 99-13-12]
RIN 2120-AA64


Airworthiness Directives; Bell Helicopter Textron Canada Model 
206L, 206L-1, 206L-3, and 206L-4 Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing priority letter 
airworthiness directive (AD), applicable to Bell Helicopter Textron 
Canada (BHTC) Model 206L, 206L-1, 206L-3, and 206L-4 helicopters, that 
currently requires visual inspections and visual checks at specified 
time intervals, and a fluorescent-penetrant inspection (FPI) for any 
cracks in the tailboom skins around the horizontal stabilizer openings. 
Inserting a copy of the priority letter AD into the Rotorcraft Flight 
Manual (RFM) is also required. This amendment revises the inspection 
procedures and specified time intervals mandated by the priority letter 
AD. This amendment is prompted by crack growth analysis that indicates 
the need to detect cracks before they propagate from underneath the 
horizontal stabilizer supports. The actions specified by this AD are 
intended to detect a crack in the tailboom skin that could result in 
separation of the tailboom from the helicopter and subsequent loss of 
control of the helicopter.

DATES: Effective July 9, 1999.
    Comments for inclusion in the Rules Docket must be received on or 
before August 23, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 99-SW-23-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.

FOR FURTHER INFORMATION CONTACT: Michael Kohner, Aerospace Engineer, 
FAA, Rotorcraft Directorate, Rotorcraft Certification Office, ASW-170, 
2601 Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5447, 
fax (817) 222-5783.

SUPPLEMENTARY INFORMATION: On January 6, 1999, the FAA issued Priority 
Letter AD 99-02-01, applicable to BHTC Model 206L, 206L-1, 206L-3, and 
206L-4 helicopters, to require visual inspections and visual checks at 
specified time intervals, and a FPI for any cracks in the tailboom 
skins around the horizontal stabilizer openings. Inserting a copy of 
the priority letter AD into the RFM is also required. That action was 
prompted by 7 reports of fatigue cracks that propagated from the edges 
of the horizontal stabilizer openings in the tailboom skins. That 
condition, if not corrected, could result in separation of the tailboom 
and subsequent loss of control of the helicopter.
    Since the issuance of that priority letter AD, further review of 
crack growth rates has shown that cracks need to be detected before 
they propagate from underneath the horizontal stabilizer supports. 
Therefore, this superseding AD requires, at specified time intervals, 
not just visually inspecting and checking the tailboom skins in the 
area of the horizontal stabilizer supports, but also removing the 
horizontal stabilizer supports and visually inspecting the edges of the 
tailboom skins around the horizontal stabilizer openings for cracks. 
Removing the horizontal stabilizer supports will allow the detection of 
cracks at an earlier stage.
    Transport Canada, which is the airworthiness authority for Canada, 
has notified the FAA that an unsafe condition may exist on BHTC Model 
206L, 206L-1, 206L-3, and 206L-4 helicopters. Transport Canada advises 
that cracks were found on the tailboom skins in the area of the 
horizontal stabilizer.
    Bell Helicopter Textron has issued BHTC Alert Service Bulletin No. 
206L-98-114, dated November 25, 1998, which specifies a pilot preflight 
check for cracks in the horizontal stabilizer area before the first 
flight of each day. Transport Canada classified this service bulletin 
as mandatory and issued AD No. CF-98-42R1, dated February 16, 1999, 
which states that a review of crack growth rates indicates the need to 
detect cracks earlier. In addition to the preflight check for cracks 
introduced by the service bulletin, the Transport Canada AD requires 
removing the horizontal stabilizer supports and visually inspecting the 
tailboom skin underneath the horizontal stabilizer supports at 
specified time intervals.
    These helicopter models are manufactured in Canada and are 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. Pursuant to this 
bilateral airworthiness agreement, Transport Canada has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of Transport Canada, reviewed all available information, and 
determined that AD action is necessary for products of these type 
designs that are certificated for operation in the United States.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other BHTC Model 206L, 206L-1, 206L-3, and 206L-4 
helicopters of the same type designs, this AD supersedes Priority 
Letter AD 99-02-01 to require:
     Prior to further flight, and thereafter, at intervals not 
to exceed 10 hours time-in-service (TIS) until a one-time FPI is 
accomplished, a visual inspection for any crack in the tailboom skins 
around the horizontal stabilizer supports;
     At intervals not to exceed 5 hours TIS, a visual preflight 
pilot check for any crack in the tailboom skins around the horizontal 
stabilizer supports;
     Within 50 hours TIS, a one-time FPI for any crack in the 
edge of the tailboom skins around the left and right horizontal 
stabilizer openings on the tailboom; and
     After completion of the one-time FPI, at intervals not to 
exceed 100 hours TIS, a visual inspection of the entire edge of the 
horizontal stabilizer opening on both sides of the tailboom for any 
crack.
    The visual check that is required at intervals not to exceed 5 
hours TIS may be performed by an owner/operator (pilot), and must be 
entered into the aircraft records showing compliance with paragraph (b) 
of this AD in accordance with sections 43.11 and

[[Page 33748]]

91.417 (a)(2)(v) of the Federal Aviation Regulations (14 CFR sections 
43.11 and 91.417 (a)(2)(v)). This AD allows a pilot to perform this 
check because it involves only a visual check for cracking in the 
tailboom skins, and can be performed equally well by a pilot or 
mechanic. These checks are additional measures to ensure that a crack 
that is visible without the aid of a magnifying glass has not developed 
during the time between maintenance inspections.
    The short compliance time involved is required because the 
previously described critical unsafe condition can adversely affect the 
structural integrity of the helicopter, and this AD must be issued 
immediately. Therefore, a visual inspection to detect any crack using a 
10-power or higher magnifying glass is required before further flight 
and at intervals not to exceed 10 hours TIS until accomplishing the 
FPI; a visual preflight pilot check for any crack is required at 
intervals not to exceed 5 hours TIS; a one-time FPI is required within 
50 hours TIS; and after completion of the one-time FPI and at intervals 
not to exceed 100 hours TIS, a visual inspection for cracks around the 
left and right horizontal stabilizer opening on both sides of the 
tailboom using a 10-power or higher magnifying glass is required.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.
    The FAA estimates that 1,546 helicopters of U.S. registry will be 
affected by this AD, that it will take approximately 2 work hours per 
helicopter to conduct a FPI; 0.5 work hour to conduct a visual 
inspection; 0.5 work hour to conduct the repetitive visual check; and 
20 work hours to replace the tailboom, if necessary. The average labor 
rate is $60 per work hour. Required parts will cost approximately 
$22,000 per tailboom. Based on these figures, the total cost impact of 
the AD on U.S. operators is estimated to be $278,280 to conduct the 
initial fluorescent-penetrant inspections and to conduct one of the 
inspections and one of the visual checks for the entire fleet; 
$36,145,480 if it is necessary to replace the tailboom on the entire 
fleet.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. 99-SW-23-AD.'' The postcard will be date stamped and 
returned to the commenter.
    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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, may be obtained from 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.

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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
(AD), Amendment 39-11207, to read as follows:

AD 99-13-12  Bell Helicopter Textron Canada: Amendment 39-11207. 
Docket No. 99-SW-23-AD. Supersedes Priority Letter AD 99-02-01, 
Docket No. 98-SW-83-AD.

    Applicability:
     Model 206L helicopters, serial numbers (S/N) 45004 
through 45153, and 46601 through 46617;
     Model 206L-1 helicopters, S/N 45154 through 45790;
     Model 206L-3 helicopters, S/N 51001 through 51613; and
     Model 206L-4 helicopters, S/N 52001 and higher,

with tailboom, part number (P/N) 206-033-004-all dash numbers, 
installed, certificated in any category.

    Note 1: This AD applies to each helicopter identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise modified, altered, or repaired in the area subject to the 
requirements of this AD. For helicopters 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 (f) 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 accomplished 
previously.
    To detect a crack in the tailboom skin and to prevent separation 
of the tailboom from the helicopter and subsequent loss of control 
of the helicopter, accomplish the following:
    (a) Before further flight, and thereafter, at intervals not to 
exceed 10 hours time-in-service (TIS) until accomplishing the one-
time fluorescent-penetrant inspection (FPI) required by paragraph 
(c)(2) of this AD,

[[Page 33749]]

visually inspect for any crack in the shaded areas shown in Figure 
1. Use a 10-power or higher magnifying glass. If any crack is found, 
replace the tailboom with an airworthy tailboom.
    (b) At intervals not to exceed 5 hours TIS, visually conduct a 
preflight check of the shaded areas shown in Figure 1 for any crack. 
If any crack is found, replace the tailboom with an airworthy 
tailboom. The visual check may be performed by an owner/operator 
(pilot) holding at least a private pilot certificate, and must be 
entered into the aircraft records showing compliance with paragraph 
(b) of this AD in accordance with sections 43.11 and 91.417 
(a)(2)(v) of the Federal Aviation Regulations (14 CFR sections 43.11 
and 91.417 (a)(2)(v)).
    (c) Within 50 hours TIS:
    (1) Remove all 4 horizontal stabilizer supports, P/N 206-023-
100-all dash numbers, from the tailboom and the horizontal 
stabilizer.
    (2) Perform a one-time FPI of the edges of the tailboom skins 
for any crack around the left and right horizontal stabilizer 
openings (Figure 1). Remove paint and primer to inspect the edges 
and exterior skin surface in the skin area at least \3/4\ inch 
around the edges of the horizontal stabilizer openings.
    (3) If a crack is found, replace the tailboom with an airworthy 
tailboom.

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[GRAPHIC] [TIFF OMITTED] TR24JN99.102



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[[Page 33751]]

    (d) At intervals not to exceed 100 hours TIS after completion of 
the FPI, accomplish the following:
    (1) Remove all 4 horizontal stabilizer supports, P/N 206-023-
100-all dash numbers, from the tailboom and the horizontal 
stabilizer.
    (2) Visually inspect the entire edge of the horizontal 
stabilizer opening on both sides of the tailboom for any crack using 
a 10-power or higher magnifying glass.
    (3) If any crack is found, replace the tailboom with an 
airworthy tailboom.
    (e) Insert a copy of this AD into the Rotorcraft Flight Manual.
    (f) 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, Rotorcraft Certification Office, 
FAA, Rotorcraft Directorate. Operators shall submit their requests 
through an FAA Principal Maintenance Inspector, who may concur or 
comment and then send it to the Manager, Rotorcraft Certification 
Office.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Rotorcraft Certification Office.

    (g) Special flight permits may be issued for a one-time flight, 
not to exceed 5 hours TIS and a maximum of one landing, in 
accordance with sections 21.197 and 21.199 of the Federal Aviation 
Regulations (14 CFR 21.197 and 21.199) to operate the helicopter to 
a location where the requirements of this AD can be accomplished. 
The visual preflight check required by paragraph (b) must be 
accomplished prior to making a one-time flight.
    (h) This amendment becomes effective on July 9, 1999.

    Note 3: The subject of this AD is addressed in Transport Canada 
(Canada) AD No. CF-98-42R1, dated February 16, 1999.

    Issued in Fort Worth, Texas, on June 16, 1999.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-15925 Filed 6-23-99; 8:45 am]
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