[Federal Register Volume 60, Number 196 (Wednesday, October 11, 1995)]
[Rules and Regulations]
[Pages 52843-52844]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-24902]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-NM-178-AD; Amendment 39-9388; AD 95-21-03]
Airworthiness Directives; Learjet Model 31A and 60 Airplanes
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 certain Learjet Model 31A and 60 airplanes. This
action requires an inspection to identify the serial numbers of the
engine fire pull switch assemblies, and replacement of the assembly
with a serviceable assembly, if necessary. This amendment is prompted
by a report indicating that certain engine fire pull switch assemblies
may contain microswitches that were manufactured with internal defects.
Such defects could result in electrical failure of the switch in the
open or closed position. The actions specified in this AD are intended
to prevent failure of the switch, which could result in the inability
of the flight crew to shut down certain systems or to arm the fire
extinguishers due to inoperation of the fire tee handle, or inadvertent
shutdown of one or both engines due to fuel starvation.
DATES: Effective October 26, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of October 26, 1995.
Comments for inclusion in the Rules Docket must be received on or
before December 11, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-178-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. The service information referenced in
this AD may be obtained from Gates Learjet, Mid-Continent Airport, P.
O. Box 7707, Wichita, Kansas 67277. This information may be examined at
the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington; or at the FAA, Wichita Aircraft Certification Office, Small
Airplane Directorate, 1801 Airport Road, Room 100, Mid-Continent
Airport, Wichita, Kansas; or at the Office of the Federal Register, 800
North Capitol Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: C. Dale Bleakney, Aerospace Engineer,
FAA, Wichita Aircraft Certification Office, Small Airplane Directorate,
1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas;
telephone (316) 946-4135; fax (316) 946-4407.
SUPPLEMENTARY INFORMATION: The FAA has received a report indicating
that a certain batch of engine fire pull switch assemblies may contain
microswitches that were manufactured with internal defects. These
assemblies are installed on Learjet Model 31A and 60 airplanes. The
left-hand (pilot) and right-hand (copilot) engine fire pull switch
assemblies contain four microswitches each, all of which may be
affected. Such internal defects can cause electrical failure of the
switch in the open or closed position, regardless of the position of
the ENG FIRE PULL tee handle. If the switch fails in the open position,
the fire tee handle would be inoperable. This condition, if not
corrected, could result in the inability of the flight crew to shut
down certain systems (such as the fuel or hydraulics system) or to arm
the fire extinguishers. Failure of the switch in the closed position
could result in fuel starvation. This condition, if not corrected,
could result in inadvertent shutdown of one or both engines during
flight.
The FAA has reviewed and approved Learjet Alert Service Bulletin SB
A31-26-3 (for Model 31A airplanes) and SB A60-26-1 (for Model 60
airplanes), both dated July 14, 1995, which describe procedures for an
inspection to identify the serial numbers of the left-hand (pilot) and
right-hand (copilot) engine fire pull switch assemblies, and
replacement of any suspect assembly with a serviceable assembly.
Replacement of suspect assemblies will restore the integrity of the
engine fire pull switch.
Since an unsafe condition has been identified that is likely to
exist or develop on other Learjet Model 31A and 60 airplanes of the
same type design, this AD is being issued to prevent electrical failure
of the microswitches in the engine fire pull switch assembly, which
could result in the inability of the flight crew to shut down certain
systems or to arm the fire extinguishers, or inadvertent shutdown of
one or both engines. This AD requires an inspection to identify the
serial numbers of the left-hand (pilot) and right-hand (copilot) engine
fire pull switch assemblies, and replacement of any suspect assembly
with a serviceable assembly. The actions are required to be
accomplished in accordance with the alert service bulletins 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 shall 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 Number 95-NM-178-AD.'' The postcard will be date stamped and
returned to the commenter.
[[Page 52844]]
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, 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 U.S.C. 106(g), 40101, 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
95-21-03 Learjet: Amendment 39-9388. Docket 95-NM-178-AD.
Applicability: Model 31A airplanes, serial numbers 31-093
through 31-108 inclusive; and Model 60 airplanes, serial numbers 60-
034 through 60-061 inclusive; certificated in any category.
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 use the authority
provided in paragraph (d) of this AD to request approval from the
FAA. This approval may address either no action, if the current
configuration eliminates the unsafe condition; or different actions
necessary to address the unsafe condition described in this AD. Such
a request should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent electrical failure of the microswitches in the engine
fire pull switch assembly, which could result in the inability of
the flight crew to shut down certain systems or to arm the fire
extinguishers, or inadvertent shutdown of one or both engines,
accomplish the following:
(a) For Model 31A airplanes: Within 50 hours time-in-service
after the effective date of this AD, perform an inspection to
identify the serial numbers of the left-hand (pilot) and right-hand
(copilot) engine fire pull switch assemblies in accordance with
Learjet Alert Service Bulletin SB A31-26-3, dated July 14, 1995.
(1) If the serial number of the assembly is not identified as
2326, 2363 through 2377 inclusive, or 3000 through 3019 inclusive:
No further action is required by this AD.
(2) If the serial number of the assembly is identified as 2326,
2363 through 2377 inclusive, or 3000 through 3019 inclusive: Prior
to further flight, replace the engine fire pull switch assembly with
a serviceable assembly in accordance with the alert service
bulletin.
(b) For Model 60 airplanes: Within 50 hours time-in-service
after the effective date of this AD, perform an inspection to
identify the serial numbers of the left-hand (pilot) and right-hand
(copilot) engine fire pull switch assemblies in accordance with
Learjet Alert Service Bulletin SB A60-26-1, dated July 14, 1995.
(1) If the serial number of the assembly is not identified as
106 through 168 inclusive: No further action is required by this AD.
(2) If the serial number of the assembly is identified as 106
through 168 inclusive: Prior to further flight, replace the engine
fire pull switch assembly with a serviceable assembly in accordance
with the alert service bulletin.
(c) As of the effective date of this AD, no person shall install
on any airplane an engine fire pull switch assembly having a serial
number identified in paragraph (c)(1) or (c)(2) of this AD, as
applicable, unless such serial number is preceded by the letters
``RS'' and accompanied by a repair date code later than June 1,
1995.
(1) For Model 31A airplanes: Serial numbers 2326, 2363 through
2377 inclusive, and 3000 through 3019 inclusive.
(2) For Model 60 airplanes: Serial numbers 106 through 168
inclusive.
(d) 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, Wichita Aircraft Certification
Office (ACO), FAA, Small Airplane Directorate. Operators shall
submit their requests through an appropriate FAA Principal
Maintenance Inspector, who may add comments and then send it to the
Manager, Wichita ACO.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Wichita ACO.
(e) 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.
(f) The inspection and replacement shall be done in accordance
with Learjet Alert Service Bulletin SB A31-26-3, dated July 14,
1995, and Learjet Alert Service Bulletin SB A60-26-1, dated July 14,
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 Gates Learjet, Mid-Continent
Airport, PO Box 7707, Wichita, Kansas 67277. Copies may be inspected
at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW.,
Renton, Washington; or at the FAA, Wichita Aircraft Certification
Office, Small Airplane Directorate, 1801 Airport Road, Room 100,
Mid-Continent Airport, Wichita, Kansas; or at the Office of the
Federal Register, 800 North Capitol Street NW., suite 700,
Washington, DC.
(g) This amendment becomes effective on October 26, 1995.
Issued in Renton, Washington, on October 2, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-24902 Filed 10-10-95; 8:45 am]
BILLING CODE 4910-13-U