[Federal Register Volume 61, Number 178 (Thursday, September 12, 1996)]
[Rules and Regulations]
[Pages 48066-48069]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-22951]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-CE-10-AD; Amendment 39-9753; AD 96-19-05]
RIN 2120-AA64


Airworthiness Directives; Fairchild Aircraft SA226 and SA227 
Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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[[Page 48067]]

SUMMARY: This amendment supersedes Airworthiness Directive (AD) 95-19-
07, which currently requires the following on Fairchild Aircraft SA226 
and SA227 series airplanes equipped with certain main landing gear 
(MLG) and nose landing gear (NLG): repetitively inspecting, using 
ultrasonic methods, the left-hand and right-hand MLG yokes and the NLG 
yokes for stress corrosion cracking, and, if any cracked yokes are 
found that exceed certain limits, replacing either the cracked yoke, 
the yoke/cylinder combination, or the affected MLG or NLG assembly. 
This action also supersedes priority letter AD 95-19-07 R1, which was 
issued to incorporate revised service information. Reports of landing 
gear failures on the affected airplanes prompted the original AD 
action. This action requires the same inspections, but requires 
replacing any MLG and NLG assembly with any cracks instead of allowing 
flight until certain crack limits are exceeded. The inability to 
determine or predict crack growth on areas where stress corrosion 
occurs on primary structure with a single-load path (MLG and NLG 
assemblies are considered such structure) prompted this action. The 
actions specified by this AD are intended to prevent MLG or NLG failure 
caused by stress corrosion cracking in the yokes, which could result in 
loss of control of the airplane during landing operations.

DATES: Effective October 1, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 1, 1996.
    Comments for inclusion in the Rules Docket must be received on or 
before November 7, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 96-CE-10-AD, Room 1558, 601 E. 
12th Street, Kansas City, Missouri 64106.
    Service information that applies to this AD may be obtained from 
Fairchild Aircraft, P.O. Box 790490, San Antonio, Texas 78279-0490; 
telephone (210) 824-9421. This information may also be examined at the 
FAA, Central Region, Office of the Assistant Chief Counsel, Attention: 
Rules Docket 96-CE-10-AD, 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: Mr. Hung Viet Nguyen, Aerospace 
Engineer, FAA, Airplane Certification Office, 2601 Meacham Boulevard, 
Fort Worth, Texas 76193-0150; telephone (817) 222-5155; facsimile (817) 
222-5960.

SUPPLEMENTARY INFORMATION:

Events Leading to the Issuance of AD 95-19-07

    Several reports of main landing gear (MLG) and nose landing gear 
(NLG) failure on Fairchild Aircraft SA226 and SA227 series airplanes 
prompted the FAA to issue Airworthiness Directive (AD) 95-19-07, 
Amendment 39-9369 (60 FR 47687, September 14, 1995). AD 95-19-07 
required the following on Fairchild Aircraft SA226 and SA227 series 
airplanes equipped with certain MLG and NLG: repetitively inspecting, 
using ultrasonic methods, the left-hand and right-hand MLG yokes and 
the NLG yokes for stress corrosion cracking, and, if any cracked yokes 
are found that exceed certain limits, replacing either the cracked 
yoke, the yoke/cylinder combination, or the affected MLG or NLG 
assembly. Accomplishment of the inspections required by AD 95-19-07 was 
required in accordance with Fairchild Service Bulletin (SB) 226-32-065, 
Fairchild SB 227-32-039, or Fairchild SB CC7-32-007, all Issued: August 
16, 1995, as applicable.
    The airplanes in the above-referenced incidents are equipped with 
at least one part number (P/N) OAS5453 MLG assembly and P/N OAS5451 NLG 
assembly. Metallurgical analysis of the yokes of the right-hand and 
left-hand MLG assemblies and NLG assemblies on several of these 
airplanes revealed that the failure was initiated by stress corrosion 
cracking of the yokes.

Explanation of the Relevant Service Information

    The service bulletins incorporated into AD 95-19-07 contain some 
incorrect procedures that could prevent an owner/operator from 
correctly accomplishing the actions required by that AD. For this 
reason, Fairchild Aircraft revised SB 226-32-065, SB 227-32-039, and SB 
CC7-32-007, each of which incorporates the following effective pages 
and revision levels:

------------------------------------------------------------------------
              Effective pages                          SB date          
------------------------------------------------------------------------
1, 5, and 8...............................  Revised: September 28, 1995.
2, 3, 4, 6, 7, and 9......................  Issued: August 16, 1995.    
------------------------------------------------------------------------

These service bulletins specify improved procedures for ultrasonically 
inspecting the left-hand and right-hand Ozone Industries, Inc. MLG yoke 
(reference: MLG assembly P/N OAS5453, all dash numbers up to and 
including -19), and Ozone Industries, Inc. NLG yoke (reference: NLG 
assembly P/N OAS5451, all dash number up to and including -17), on 
Fairchild Aircraft SA226 and SA227 series airplanes.

The Need to Revise AD 95-19-07

    The FAA determined that the revised service information should be 
incorporated into AD 95-19-07 to allow for proper inspection of the MLG 
and NLG yokes of the affected airplanes, and issued priority letter AD 
95-19-07 R1 to prevent MLG or NLG failure caused by stress corrosion 
cracks in the yokes, which could result in loss of control of the 
airplane during landing operations. The priority letter revised AD 95-
19-07 by (1) retaining the repetitive inspections and possible 
replacement required by AD 95-19-07; and (2) incorporating the revised 
service bulletins to require accomplishment of the actions in 
accordance with corrected and clarified procedures.

Reason for This Action

    After in-depth analysis, the FAA has established a policy to not 
allow airplane operation when known cracks exist in primary structure 
(MLG and NLG assemblies are considered such structure). The FAA makes 
allowances on this policy to account for parts availability provided 
analysis shows that an interim, acceptable level of safety can be 
maintained through a short-term, repetitive inspection program.
    For this reason, the FAA has determined that the crack limits in 
priority letter AD 95-19-07 R1 and AD 95-19-07, Amendment 39-9369, 
should be eliminated and that AD action should be taken to require 
immediate replacement of any cracked MLG or NLG assembly. Because 
analysis shows that a repetitive inspection program can provide an 
interim acceptable level of safety, the FAA will allow a grace period 
for those owners/operators with airplanes where a crack is found in the 
MLG or NLG yoke during the initial inspection required by this action.

Explanation of the Provisions of This AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other Fairchild Aircraft SA226 and SA227 series 
airplanes of the same type design, this AD supersedes both priority 
letter AD 95-19-07 R1 and AD 95-19-07, Amendment 39-9369, with a new AD 
that retains the requirement of repetitively inspecting, using 
ultrasonic methods, the left-hand and right-hand MLG yokes and the NLG 
yokes for stress corrosion cracking, and

[[Page 48068]]

requires replacing either the cracked yoke, the yoke/cylinder 
combination, or the affected MLG or NLG assembly, if any crack is 
found. Accomplishment of the required inspections is in accordance with 
Fairchild SB 226-32-065, Fairchild SB 227-32-039, or Fairchild SB CC7-
32-007, as applicable. Each of these service bulletins incorporates the 
following effective pages and revision levels:

------------------------------------------------------------------------
              Effective pages                          SB date          
------------------------------------------------------------------------
1, 5, and 8...............................  Revised: September 28, 1995.
2, 3, 4, 6, 7, and 9......................  Issued: August 16, 1995.    
------------------------------------------------------------------------

Accomplishment of the replacement is in accordance with the applicable 
maintenance manual.
    Since a situation exists (possible loss of control of the airplane 
during landing operations) that requires the immediate adoption of this 
regulation, it is found that notice and opportunity for public prior 
comment hereon are impracticable, and that good cause exists for making 
this amendment effective in less than 30 days.

Compliance Time Criteria

    The compliance time of this AD is presented in both calendar time 
and hours time-in-service (TIS). Cracking of certain MLG yokes and NLG 
yokes on the affected airplanes is caused by stress corrosion, which 
starts as a result of high local stress (in the area where the piston 
was shrink fitted to the yoke) incurred through operation. Corrosion 
can then develop regardless of whether the airplane is in flight or on 
the ground. The cracks may not be noticed initially as a result of the 
stress loads, but could then progress as a result of corrosion. The 
stress incurred during flight operations or temperature changes could 
then cause rapid crack growth. In order to ensure that these stress 
corrosion cracks do not go undetected, a compliance time of specific 
hours TIS and calendar time (whichever occurs first) is utilized.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting immediate flight safety and, thus, was not 
preceded by notice and opportunity to 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 above. 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. 96-CE-10-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    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 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 (otherwise, an evaluation is 
not required). A copy of it, if filed, may be obtained from the Rules 
Docket.

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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Airworthiness Directive 
(AD) 95-19-07, Amendment 39-9369 (60 FR 47687, September 14, 1995), and 
by adding a new AD to read as follows:

96-19-05  Fairchild Aircraft: Amendment 39-9753, Docket No. 96-CE-
10-AD. Supersedes both AD 95-19-07, Amendment 39-9369, and priority 
letter AD 95-19-07 R1.

    Applicability: Models SA226-T, SA226-AT, SA226-TC, SA226-T(B), 
SA227-AC, SA227-AT, SA227-BC, SA227-TT, SA227-CC, and SA227-DC 
airplanes (all serial numbers), certificated in any category, that 
are equipped with one or more of the following:
    1. Ozone Industries, Inc. main landing gear (MLG) yoke 
(reference: MLG assembly part number OAS5453, all dash numbers up to 
and including -19); or
    2. Ozone Industries, Inc. nose landing gear (NLG) yoke 
(reference: NLG assembly part number OAS5451, all dash numbers up to 
and including -17).

    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 (g) 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 initially as follows and thereafter 
as indicated in the body of this AD:
    1. Within the next 100 hours time-in-service (TIS) after the 
effective date of this AD or within the next 3 months after the 
effective date of this AD, whichever occurs first; and
    2. Upon the installation of one of the affected MLG or NLG 
assemblies or yokes.
    To prevent MLG or NLG failure caused by stress corrosion cracks 
in the yokes, which could result in loss of control of the airplane 
during landing operations, accomplish the following:

[[Page 48069]]

    (a) Inspect, using ultrasonic methods, both sides of the left-
hand and right-hand MLG and NLG yokes for stress corrosion cracking 
in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of 
Fairchild Service Bulletin (SB) 226-32-065, Fairchild SB 227-32-039, 
or Fairchild SB CC7-32-007, as applicable. Each of these service 
bulletins incorporates the following effective pages and revision 
levels:

------------------------------------------------------------------------
              Effective pages                          SB date          
------------------------------------------------------------------------
1, 5, and 8...............................  Revised: September 28, 1995.
2, 3, 4, 6, 7, and 9......................  Issued: August 16, 1995.    
------------------------------------------------------------------------

    (b) If no cracks are found during the initial inspection 
required by paragraph (a) of this AD, accomplish the following:
    (1) Prior to further flight after the initial inspection 
required by this AD, clean the MLG and NLG yoke and piston in 
accordance with FIGURE 2 of the service bulletins referenced in this 
AD, unless already accomplished;
    (2) Prior to further flight after the initial inspection 
required by this AD, apply a small bead of Products Research and 
Chemical Corporation PR-1422 or PR-1435 sealant to the MLG and NLG 
yoke as shown in FIGURE 2 of the service bulletins referenced in 
this AD, and as described in the SA226/227 Series Service Repair 
Manual, Chapter 51-30-03, Standard Practices--Sealing, unless 
already accomplished; and
    (3) Reinspect the MLG and NLG yokes at intervals not to exceed 
2,500 hours TIS or 12 months, whichever occurs first, provided no 
cracks are found. If cracks are found, prior to further flight, 
replace the cracked part with a new or serviceable part in 
accordance with the applicable maintenance manual, and accomplish 
the cleaning of and sealant application to the MLG and NLG yoke and 
piston as specified in paragraphs (b)(1) and (b)(2) of this AD. The 
replacement may be accomplished by replacing the cracked yoke, the 
total gear assembly, or the yoke/cylinder combination.
    (c) If a crack is found during the initial inspection of this 
AD, replace the cracked part with a new or serviceable part in 
accordance with the applicable maintenance manual, and accomplish 
the cleaning of and sealant application to the MLG and NLG yoke and 
piston as specified in paragraphs (b)(1) and (b)(2) of this AD. The 
replacement may be accomplished by replacing the cracked yoke, the 
total gear assembly, or the yoke/cylinder combination. Replace any 
cracked part in accordance with the following schedule:
    (1) With a crack found with a length more than 1.5 inches in 
length: PRIOR TO FURTHER FLIGHT;
    (2) With a crack found with a length more than 1 inch but not 
more than 1.5 inches: WITHIN THE NEXT 300 HOURS TIS AFTER THE 
INITIAL INSPECTION REQUIRED BY THIS AD OR WITHIN THE NEXT 60 DAYS 
AFTER THE INITIAL INSPECTION REQUIRED BY THIS AD, WHICHEVER OCCURS 
FIRST;
    (3) With a crack found with a length more than .75 inch but not 
more than 1 inch: WITHIN THE NEXT 400 HOURS TIS AFTER THE INITIAL 
INSPECTION REQUIRED BY THIS AD OR WITHIN THE NEXT 80 DAYS AFTER THE 
INITIAL INSPECTION REQUIRED BY THIS AD, WHICHEVER OCCURS FIRST;
    (4) With a crack found with a length more than .50 inch but not 
more than .75 inch: WITHIN THE NEXT 500 HOURS TIS AFTER THE INITIAL 
INSPECTION REQUIRED BY THIS AD OR WITHIN THE NEXT 100 DAYS AFTER THE 
INITIAL INSPECTION REQUIRED BY THIS AD, WHICHEVER OCCURS FIRST; and
    (5) With a crack found with a length less than 0.50 inch: WITHIN 
THE NEXT 600 HOURS TIS AFTER THE INITIAL INSPECTION REQUIRED BY THIS 
AD OR WITHIN THE NEXT 120 DAYS AFTER THE INITIAL INSPECTION REQUIRED 
BY THIS AD, WHICHEVER OCCURS FIRST.
    (d) Replacing a MLG or NLG yoke with either Ozone Industries, 
Inc. MLG yoke (reference: MLG assembly part number OAS5453, all dash 
numbers up to and including--19), or Ozone Industries, Inc. NLG yoke 
(reference: NLG assembly part number OAS5451, all dash numbers up to 
and including--17) re-establishes the effectivity of this AD.
    (1) Repetitive inspections are required upon installation and at 
intervals not to exceed 2,500 hours TIS or 12 months, whichever 
occurs first, provided no cracks are found.
    (2) If cracks are found, prior to further flight, replace the 
cracked part with a new or serviceable part in accordance with the 
applicable maintenance manual, and accomplish the cleaning of and 
sealant application to the MLG and NLG yoke and piston as specified 
in paragraphs (b)(1) and (b)(2) of this AD. The replacement may be 
accomplished by replacing the cracked yoke, the total gear assembly, 
or the yoke/cylinder combination.
    (3) The crack limit replacement compliance times specified in 
paragraph (c) of this AD only apply when cracks are found during the 
initial inspection required by this AD. If any crack of any length 
is found during a subsequent (any repetitive) inspection, the part 
must be replaced PRIOR TO FURTHER FLIGHT.
    (e) The MLG and NLG yokes to which this AD applies are 
manufactured by Ozone Industries, Inc. Replacing these yokes with 
approved parts, other than the following Ozone Industries, Inc. MLG 
and NLG yokes eliminates the repetitive inspection requirements of 
this AD:
    (1) Ozone Industries, Inc. MLG yoke (reference: MLG assembly 
part number OAS5453, all dash numbers up to and including--19).
    (2) Ozone Industries, Inc. NLG yoke (reference: NLG assembly 
part number OAS5451, all dash numbers up to and including--17).
    (f) 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.
    (g) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Airplane Certification Office (ACO), FAA, 
2601 Meacham Boulevard, Fort Worth, Texas 76193-0150. The request 
shall be forwarded through an appropriate FAA Maintenance Inspector, 
who may add comments and then send it to the Manager, Fort Worth 
ACO. Alternative methods of compliance approved in accordance with 
either priority letter AD 95-19-07 R1 or AD 95-19-07, Amendment 39-
9369 (both superseded by this action), are not considered approved 
as alternative methods of compliance with this AD.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Fort Worth ACO.

    (h) The inspections required by this AD shall be done in 
accordance with Fairchild Service Bulletin 226-32-065, Fairchild 
Service Bulletin 227-32-039, or Fairchild Service Bulletin CC7-32-
007, as applicable. Each of these service bulletins incorporates the 
following effective pages and revision levels:

------------------------------------------------------------------------
              Effective pages                          SB date          
------------------------------------------------------------------------
1, 5, and 8...............................  Revised: September 28, 1995.
2, 3, 4, 6, 7, and 9......................  Issued: August 16, 1995.    
------------------------------------------------------------------------

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 Fairchild Aircraft, P.O. Box 790490, 
San Antonio, Texas 78279-0490. 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.
    (i) This amendment (39-9753) supersedes AD 95-19-07, Amendment 
39-9369, and priority letter AD 95-19-07 R1.
    (j) This amendment (39-9753)1 becomes effective on October 1, 
1996.

    Issued in Kansas City, Missouri, on September 3, 1996.
Henry A. Armstrong,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-22951 Filed 9-11-96; 8:45 am]
BILLING CODE 4910-13-U