AD Amdt-39-9365

[Federal Register Volume 60, Number 176 (Tuesday, September 12, 1995)]
[Rules and Regulations]
[Pages 47265-47266]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 95-22457]



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Federal Register / Vol. 60, No. 176 / Tuesday, September 12, 1995 / 
Rules and Regulations


[[Page 47265]]


DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-25-AD; Amendment 39-9365; AD 95-19-04]


Airworthiness Directives; Learjet Model 35, 35A, 36, 36A, 55, 
55B, and 55C Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Learjet Model 35, 35A, 36, 36A, 55, 55B, and 55C 
airplanes, that requires installation of a placard on the instrument 
panel in the cockpit to advise the flightcrew that the Omega navigation 
system may be inoperative at certain engine speeds. This amendment is 
prompted by reports of loss of certain navigation signals during 
extended over water operation. The actions specified by this AD are 
intended to prevent excessive deviation from the intended flight path 
due to loss of navigation signals, which could result in a potentially 
low-fuel condition or a traffic conflict.

DATES: Effective October 12, 1995.

ADDRESSES: 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 Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 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, 
ACE-130W, Systems and Equipment Branch, FAA, Wichita Aircraft 
Certification Office, Small Airplane Directorate, 1801 Airport Road, 
Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 
946-4135; fax (316) 946-4407.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Learjet Model 35, 35A, 36, 
36A, 55, 55B, and 55C airplanes was published in the Federal Register 
on May 16, 1995 (60 FR 26003). That action proposed to require 
installation of a placard on the instrument panel in the cockpit to 
advise the flightcrew that the Omega navigation system may be 
inoperative when engine speed reaches 92.5% N<INF>2. -
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were submitted in response 
to the proposal or the FAA's determination of the cost to the public. 
The FAA has determined that air safety and the public interest require 
the adoption of the rule as proposed. -
    There are approximately 710 Learjet Model 35, 35A, 36, 36A, 55, 
55B, and 55C airplanes of the affected design in the worldwide fleet. 
The FAA estimates that 177 airplanes of U.S. registry will be affected 
by this AD, that it will take approximately 1 work hour per airplane to 
accomplish the required actions, and that the average labor rate is $60 
per work hour. The cost of required parts (local manufacture of a 
placard) is negligible. Based on these figures, the total cost impact 
of the AD on U.S. operators is estimated to be $10,620, or $60 per 
airplane. -
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished any of the 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted. -
    Should an operator elect to accomplish the optional terminating 
action that is provided by this AD action, it will take approximately 
14 work hours to accomplish it, at an average labor rate of $60 per 
work hour. The cost of required parts will be approximately $3,050 per 
airplane. Based on these figures, the total cost impact of the optional 
terminating action is $3,890 per airplane. -
    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. -
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a 
significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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 USC 106(g), 40101, 40113, 44701.


Sec. 39.13  [Amended] -

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

95-19-04  Learjet: Amendment 39-9365. Docket 95-NM-25-AD.

     -Applicability: Model 5, 35A, 36, 36A, 55, 55B, and 55C 
airplanes; equipped with 

[[Page 47266]]
Global Wulfsburg GNS 500, GNS-1000, and GNS-X Flight Management 
Systems, 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 excessive deviation from the intended flight path 
which, if the aircraft is on an extended overwater operation, may 
lead to a potential low-fuel condition or a traffic conflict 
operation, accomplish the following: -
    (a) Within 60 days after the effective date of this AD, install 
a placard in a prominent location on the instrument panel that 
states: ``VLF/OMEGA MAY BE INOPERATIVE AT 92.5% N<INF>2'' -
    (b) For Model 35 airplanes, serial numbers 35-001 through 35-603 
inclusive; and Model 36, serial numbers 36-001 through 36-053 
inclusive: Installation of a GNS 500/1000 generator band reject 
filter in accordance with Gates Learjet Airplane Accessory Kit Model 
AAK 85-1, dated January 14, 1986, as revised by Airplane Accessory 
Kit Change Notice AAK-85-1, Change 1 (undated), constitutes 
terminating action for the placard requirement of paragraph (a) of 
this AD. Following installation of the filter, the placard required 
by paragraph (a) of this AD may be removed. -
    (c) For Model 55 airplanes, serial numbers 55-003 through 55-124 
inclusive: Installation of a GNS 500/1000 generator band reject 
filter in accordance with Gates Learjet Airplane Accessory Kit Model 
55 AAK 55-85-2, dated January 14, 1986, as revised by Airplane 
Accessory Kit Change Notice AAK No. AAK55-85-2, Change 1 (undated), 
constitutes terminating action for the placard requirement of 
paragraph (a) of this AD. Following installation of the filter, the 
placard required by paragraph (a) of this AD may be removed. -
    (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, 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) This amendment becomes effective on October 12, 1995.

    Issued in Renton, Washington, on September 5, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-22457 Filed 9-11-95; 8:45 am]
BILLING CODE 4910-13-U