[Federal Register Volume 59, Number 186 (Tuesday, September 27, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-23718]
[[Page Unknown]]
[Federal Register: September 27, 1994]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 93-NM-191-AD; Amendment 39-8748; AD 93-23-12]
Airworthiness Directives; Learjet Model 60 Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; correction.
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SUMMARY: This document corrects information in an existing
airworthiness directive (AD), applicable to certain Learjet Model 60
airplanes, that currently requires deactivation of the auxiliary cabin
and cockpit heating systems and installation of placards. This action
corrects the applicability of the rule. This action is necessary to
ensure that only airplanes subject to the addressed unsafe condition
are subject to the requirements of the rule.
DATES: Effective December 15, 1993.
The incorporation by reference of certain publications listed in
the regulations was previously approved by the Director of the Federal
Register as of December 15, 1993 (58 FR 63060, November 30, 1993).
ADDRESSES: The service information referenced in this AD may be
obtained from Learjet, Inc., P.O. Box 7707, Wichita, Kansas 67277-7707.
This information may be examined at the Federal Aviation Administration
(FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue
SW., Renton, Washington; or at the FAA, Wichita Aircraft Certification
Office, 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,
Systems and Equipment Branch, ACE-130W, FAA, Small Airplane
Directorate, Wichita Aircraft Certification Office, 1801 Airport Road,
Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316)
946-4135; fax (316) 946-4407.
SUPPLEMENTARY INFORMATION: On November 22, 1993, the FAA issued AD 93-
23-12, amendment 39-8748 (58 FR 63060, November 30, 1993), to require
deactivation of the auxiliary cabin and cockpit heating systems on all
Learjet Model 60 airplanes, and the installation of a placard stating,
``Cabin and Cockpit Heat Inop.'' That action was prompted by a report
of a fire in the aft fuselage of one airplane, which had resulted from
miswiring that was installed in an auxiliary cabin heater during
manufacture. The actions required by that AD are intended to prevent
overheating of the auxiliary cabin and cockpit heaters, which
potentially could result in a fire.
Recently, the FAA has become aware of the fact that the
applicability of the AD is unnecessarily broad. In developing the AD,
the FAA intended that its applicability be coextensive with the
effectivity listing of Learjet Alert Service Bulletin SB A60-21-1,
dated November 1, 1993. (That service bulletin was referenced in the
rule as the appropriate source of service information.) That service
bulletin indicates that only airplanes having serial numbers 60-002
through 60-021, inclusive, are subject to the addressed unsafe
condition; all other airplanes of this model were modified during
production in such a way so as to preclude the unsafe condition.
However, the applicability of the AD, as published, inadvertently
indicated that all airplanes of this model were applicable to the
requirements of the AD, rather than just those having serial numbers
60-002 through 60-021. That inadvertent action incorrectly made the
requirements of the AD redundant for airplanes other than those with
the specified serial numbers.
The FAA has determined that it is appropriate to take action to
correct the applicability of AD 93-23-12 to specify only airplanes that
are subject to the addressed unsafe condition. Therefore, action must
be taken to correctly limit the AD's applicability to only Learjet
Model 60 airplanes having serial numbers 60-002 through 60-021,
inclusive.
Action is taken herein to correct the error and to correctly add
the AD as an amendment to section 39.13 of the Federal Aviation
Regulations (14 CFR 39.13). The effective date of the rule remains
December 15, 1993.
The final rule is being reprinted in its entirety for the
convenience of affected operators.
Since this action only corrects an inadvertent error in the
applicability of the rule, so as to eliminate airplanes not subject to
the identified unsafe condition, it has no adverse economic impact and
imposes no additional burden on any person. Therefore, notice and
public procedures hereon are unnecessary.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Correction
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. 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 correctly adding the following
airworthiness directive (AD):
93-23-12 Learjet, Inc.: Amendment 39-8748. Docket 93-NM-191-AD.
Applicability: Model 60 airplanes having serial numbers 60-002
through 60-021, inclusive, certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent overheating of the auxiliary cabin and cockpit
heaters, which could potentially result in a fire, accomplish the
following:
(a) Within 10 flight hours after the effective date of this AD,
deactivate the auxiliary cabin and cockpit heating systems; and
install a placard stating, ``Cabin and Cockpit Heat Inop'' adjacent
to the AUX HT Switch (S44) on the co-pilot's switch panel; in
accordance with Learjet Alert Service Bulletin SB A60-21-1, dated
November 1, 1993.
(b) 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: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Wichita ACO.
(c) Special flight permits may be issued in accordance with
section 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.
(d) The deactivation and placard installation shall be done in
accordance with Learjet Alert Service Bulletin SB A60-21-1, dated
November 1, 1993. 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, as of December 15, 1993 (58 FR 63060,
November 30, 1993). Copies may be obtained from Learjet, Inc., P.O.
Box 7707, Wichita, Kansas 67277-7707. Copies may be inspected at the
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington; or at the FAA, Wichita ACO, 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.
(e) This amendment becomes effective on December 15, 1993.
Issued in Renton, Washington, on September 20, 1994.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-23718 Filed 9-26-94; 8:45 am]
BILLING CODE 4910-13-U