[Federal Register Volume 59, Number 49 (Monday, March 14, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-5704]


[[Page Unknown]]

[Federal Register: March 14, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-ANE-09; Amendment 39-8853; AD 94-06-05]

 

Airworthiness Directives; Hamilton Standard 14RF Series 
Propellers

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to Hamilton Standard 14RF series propellers. This action 
adopts new torquing procedures for the propeller hub retaining nuts, 
requires initial and repetitive torque checks of propeller hub 
retaining nuts using those new procedures. In addition, this AD 
requires repetitive visual inspections for external propeller oil, 
investigation, and removal from service of propellers hubs found 
cracked or with undetermined leakage. This amendment is prompted by 
reports of cracks in propeller hubs that initiate in hub dowel pin 
holes at the connection of the hub to the engine flange. The actions 
specified in this AD are intended to prevent propeller hub cracking and 
loss of engine oil, and possible loss of a propeller blade or hub.

DATES: Effective March 29, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 29, 1994.
    Comments for inclusion in the Rules Docket must be received on or 
before May 13, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 94-ANE-09, 12 New England 
Executive Park, Burlington, MA 01803-5299.
    The service information referenced in this AD may be obtained from 
Hamilton Standard, One Hamilton Road, Windsor Locks, CT 06096-1010. 
This information may be examined at the FAA, New England Region, Office 
of the Assistant Chief Counsel, 12 New England Executive Park, 
Burlington, MA; or at the Office of the Federal Register, 800 North 
Capitol Street NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Francis X. Walsh, Aerospace Engineer, 
Boston Aircraft Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; 
telephone (617) 238-7158, fax (617) 238-7199.

SUPPLEMENTARY INFORMATION: The Federal Aviation Administration (FAA) 
has received reports of cracks found in some Hamilton Standard Model 
14RF-9, 14RF-19, and 14RF-21 propeller hubs. Through testing and field 
investigation the FAA has determined that insufficient torque of the 
propeller hub retaining nuts has resulted in damage by fretting within 
the dowel holes and subsequent cracks initiating in the hub dowel pin 
holes at the connection of the hub to the engine flange. The FAA has 
also determined that the present torquing procedures for propeller hub 
retaining nuts on this model propeller are insufficient to control 
fretting during the conditions experienced in service. Therefore, 
through engineering analysis, the FAA has determined that new, more 
stringent torquing procedures must be applied to this propeller model 
to mitigate this fretting condition. Cracks that may be caused by this 
condition can be detected by oil leakage not explained by other 
conditions such as leaks in the blade seal, the pressure relief valve, 
or actuator assembly. Since undetermined oil leakage is a good 
indication of cracks in the propeller hub, the FAA has also determined 
that propellers hubs with unexplained oil leakage must be removed from 
service and inspected for cracks prior to return to service. This 
fretting condition, if not corrected, could result in propeller hub 
cracking and loss of engine oil, and possible loss of a propeller blade 
or hub.
    The FAA has reviewed and approved the technical contents of 
Temporary Revision (TR) No. 61-6, dated March 15, 1993, and TR No. 61-
7, dated July 27, 1993, to Hamilton Standard Maintenance Manual (MM) 
P5186, applicable to Model 14RF-9 propellers; TR No. 61-6, dated April 
8, 1993, and TR No. 61-7, dated July 27, 1993, to Hamilton Standard MM 
P5199, applicable to Model 14RF-19 propellers; and TR No. 61-4, dated 
March 15, 1993, and TR No. 61-5, dated July 27, 1993, to Hamilton 
Standard MM P5189, applicable to Model 14RF-21 propellers. These TR's 
describe the new torquing procedures for torque checks of propeller hub 
retaining nuts, and procedures for inspecting propeller hubs for 
cracks.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other Hamilton Standard 14RF series propellers of 
the same type design, this AD is being issued to prevent propeller hub 
cracking and loss of engine oil, and possible loss of a propeller blade 
or hub. This AD requires an initial torque check of the propeller hub 
retaining nuts within 30 days after the effective date of this AD, the 
implementation of a new, more stringent hub retaining nut tightening 
procedure, and repetitive torque checks of the hub retaining nuts. If 
the torque checks of the hub retaining nuts do not meet the acceptance 
critieria of the applicable TR's during the initial or subsequent 
repetitive checks, then the propeller hub must be removed from service 
and inspected for cracks prior to return to service. Propeller hubs 
with crack indications must be removed from service and replaced with a 
serviceable propeller hub prior to further flight. The FAA's analysis 
indicates that 30 days will be sufficient to schedule the torque checks 
without adversely affecting flight safety.
    Subsequent to an acceptable initial torque check and the 
implementation of the new hub retaining nut tightening procedure, this 
AD requires a one-time entry in the propeller maintenance records that 
the new tightening procedure was incorporated. In addition, all future 
propeller installations should follow the new installation and hub 
retaining nut tightening procedure.
    The AD will thereafter require repetitive torque checks at 
intervals not to exceed 500 hours time in service since the last 
inspection. In addition, this AD requires repetitive visual inspections 
for external propeller oil, investigation, and removal from service of 
propellers hubs found cracked or with undetermined leakage. These 
inspections must be performed at intervals not to exceed 70 hours time 
in service (TIS) since the last inspection, or at line checks, 
whichever occurs first. If the leakage is found to be caused by other 
than a leak in the blade seal, the pressure relief valve, or actuator 
assembly, the leakage may be due to a propeller hub crack and the 
propeller must be removed from service and replaced with a serviceable 
propeller prior to further flight. The actions would be required to be 
accomplished in accordance with the applicable TR's to the MM's 
described previously.
    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.

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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 94-ANE-09.'' 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 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, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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. 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 the following new 
airworthiness directive:

94-06-05  Hamilton Standard: Amendment 39-8853. Docket 94-ANE-09.

    Applicability: Hamilton Standard Model 14RF-9, 14RF-19, and 
14RF-21 propellers, installed on but not limited to Embraer EMB-120 
series, Construcciones Aeronauticas, SA (CASA) CN-235 series, and 
SAAB-SCANIA SF340 series aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent propeller hub cracking and loss of engine oil, and 
possible loss of a propeller blade or hub, accomplish the following:
    (a) Within 30 days after the effective date of this 
airworthiness directive (AD), perform an initial torque check of the 
propeller hub retaining nuts, as follows:
    (1) For Hamilton Standard Model 14RF-9 propellers, in accordance 
with Temporary Revision (TR) No. 61-6, dated March 15, 1993, to 
Hamilton Standard Maintenance Manual (MM) P5186.
    (2) For Hamilton Standard Model 14RF-19 propellers, in 
accordance with TR No. 61-6, dated April 8, 1993, to Hamilton 
Standard MM P5199.
    (3) For Hamilton Standard Model 14RF-21 propellers, in 
accordance with TR No. 61-4, dated March 15, 1993, to Hamilton 
Standard MM P5189.
    (b) If propeller hub retaining nuts are found not to meet the 
acceptance criteria in accordance with the applicable TR to the 
Hamilton Standard MM's during the initial torque check in accordance 
with paragraph (a), and during the repetitive torque checks 
performed in accordance with paragraph (e) of this AD, remove the 
propeller hub from service and inspect for cracks in accordance with 
the applicable TR's listed in paragraph (a) of this AD. Remove 
propeller hubs with crack indications and replace with serviceable 
propeller hubs prior to further flight.
    (c) If the initial propeller hub retaining nut torque check is 
acceptable in accordance with the applicable TR listed in paragraph 
(a) of this AD, support the propeller with an appropriate lifting 
fixture and loosen all the propeller hub retaining nuts. Tighten the 
propeller hub retaining nuts as follows:
    (1) For Hamilton Standard Model 14RF-9 propellers, in accordance 
with TR No. 61-7, dated July 27, 1993, to Hamilton Standard MM 
P5186.
    (2) For Hamilton Standard Model 14RF-19 propellers, in 
accordance with TR No. 61-7, dated July 27, 1993, to Hamilton 
Standard MM P5199.
    (3) For Hamilton Standard Model 14RF-21 propellers, in 
accordance with TR No. 61-5, dated July 27, 1993, to Hamilton 
Standard MM P5189.
    (d) Make a one-time entry into propeller maintenance records to 
record:
    (1) That the initial torque check was performed;
    (2) The propeller hub retaining nuts were loosened and tightened 
in accordance with paragraph (c) of this AD; and
    (3) The torque values.
    (e) Thereafter, perform repetitive torque checks at intervals 
not to exceed 500 hours time in service since the last inspection, 
in accordance with the applicable TR to the Hamilton Standard MM's 
listed in paragraph (a) of this AD.
    (f) Install all propellers after the effective date of this AD 
using the propeller hub retaining nut tightening procedure defined 
in the applicable TR to the Hamilton Standard MM's listed in 
paragraph (c) of this AD. Record the torque values in accordance 
with paragraph (d) of this AD.
    (g) Visually inspect and investigate all external propeller oil 
leakage at the next line check, or within 70 hours TIS after the 
effective date of this AD, whichever occurs first. If the leakage is 
found to be caused by other than a leak in the blade seal, the 
pressure relief valve, or actuator assembly, the propeller must be 
removed from service and replaced with a serviceable propeller prior 
to further flight.
    (h) Thereafter, visually inspect and investigate all external 
propeller oil leakage at intervals not to exceed 70 hours TIS since 
the last inspection, or at the next line check, whichever occurs 
first. If the leakage is found to be caused by other than a leak in 
the blade seal, the pressure relief valve, or actuator assembly, the 
propeller must be removed from service and replaced with a 
serviceable propeller prior to further flight.
    (i) 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, Boston Aircraft Certification 
Office. The request should be forwarded through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, Boston Aircraft Certification Office.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Boston Aircraft Certification 
Office.

    (j) Special flight permits may be issued in accordance with FAR 
21.197 and 21.199 to operate the aircraft to a location where the 
requirements of this AD can be accomplished.
    (k) The torque checks, retightening, and installation procedures 
shall be done in accordance with the following service documents: 

------------------------------------------------------------------------
               Document No.                   Pages          Date       
------------------------------------------------------------------------
TR No. 61-6 to Hamilton Standard MM P5186..      1-8  Mar. 15, 1993.    
Total pages: 8.                                                         
TR No. 61-7 to Hamilton Standard MM P5186..      1-9  July 27, 1993.    
Total pages: 9.                                                         
TR No. 61-6 to Hamilton Standard MM P5199..      1-6  Apr. 8, 1993.     
Total pages: 6.                                                         
TR No. 61-7 to Hamilton Standard MM P5199..      1-7  July 27, 1993.    
Total pages: 7.                                                         
TR No. 61-4 to Hamilton Standard MM P5189..      1-8  Mar. 15, 1993.    
Total pages: 8.                                                         
TR No. 61-5 to Hamilton Standard MM P5189..      1-7  July 27, 1993.    
Total pages: 7.                                                         
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    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 Hamilton Standard, One Hamilton 
Road, Windsor Locks, CT 06096-1010. Copies may be inspected at the 
FAA, New England Region, Office of the Assistant Chief Counsel, 12 
New England Executive Park, Burlington, MA; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.
    (l) This amendment becomes effective on March 29, 1994.

    Issued in Burlington, Massachusetts, on March 7, 1994.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 94-5704 Filed 3-11-94; 8:45 am]
BILLING CODE 4910-13-P