[Federal Register Volume 60, Number 11 (Wednesday, January 18, 1995)]
[Proposed Rules]
[Pages 3592-3593]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-1135]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-220-AD]


Airworthiness Directives; Raytheon Corporate Jets Models DH/BH/
HS/BAe 125-1 to -700 Series Airplanes; BAe 125-800A Airplanes; and 
Hawker 800 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Raytheon Corporate Jets 
Models DH/BH/HS/BAe 125-1 to -700 series, BAe 125-800A, and Hawker 800 
series airplanes. This proposal would require replacement of the 
existing standby static inverter with an inverter that incorporates a 
circuit board assembly sealed with a conformal coating. This proposal 
is prompted by reports of failure of the standby static inverter caused 
by electrical shorting from moisture condensing on the printed circuit 
boards (PCB), due to aberrations in the PCB conformal coating. The 
actions specified by the proposed AD are intended to prevent 
malfunction of the standby static inverter due to exposure to moisture 
caused by inadequate insulation coating of the circuit board assembly. 
Malfunction or failure of the standby static inverter, when its use is 
necessary, could result in the loss of electric power for certain 
equipment critical to safety of flight.

DATES: Comments must be received by February 27, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-220-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Raytheon Corporate Jets, Inc., 3 Bishops Square, St. 
Albans Road West, Hatfield, Hertfordshire, AL109NE, United Kingdom. 
This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: William Schroeder, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2148; fax (206) 227-1320.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal 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-NM-220-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules 
Docket No. 94-NM-220-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Civil Aviation Authority (CAA), which is the airworthiness 
authority for the United Kingdom, recently notified the FAA that an 
unsafe condition may exist on certain Raytheon Corporate Jets Models 
DH/BH/HS/BAe 125-1 to -700, BAe 125-800A, and Hawker 800 series 
airplanes. The CAA advises that it has received reports of failure of 
the standby static inverter on certain of these airplanes. Failure was 
caused by electrical shorting from moisture condensing on the printed 
circuit boards (PCB), due to aberrations in the PCB's conformal 
coating. Investigation has revealed that certain circuit boards in the 
inverters have conformal coatings that were applied improperly. The 
purpose of this coating is to protect the electric/electronic circuits 
from moisture. Improper coating of the circuit boards can allow 
moisture to condense on the PCB; this could cause an electrical short 
that, subsequently, could result in a malfunction or failure of the 
standby static inverter. This condition, if not corrected, could result 
in the loss of all alternating current (AC) electric power for 
equipment that is critical to safety of flight.
    Raytheon Corporate Jets has issued Hawker Service Bulletin SB.24-
308-7673A, Revision 1, dated July 11, 1994, which describes procedures 
for removing the existing standby static inverter and replacing it with 
a printed circuit board assembly that is properly sealed with a 
conformal coating. The CAA classified this service bulletin as 
mandatory and issued British airworthiness directive 005-05-94 in order 
to assure the continued [[Page 3593]] airworthiness of these airplanes 
in the United Kingdom.
    This airplane model is manufactured in the United Kingdom and is 
type certificated for operation in the United States under the 
provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 
21.29) and the applicable bilateral airworthiness agreement. Pursuant 
to this bilateral airworthiness agreement, the CAA has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of the CAA, reviewed all available information, and determined 
that AD action is necessary for products of this type design that are 
certificated for operation in the United States.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would require replacement of the 
existing standby static inverters with a printed circuit board assembly 
that is properly sealed with a conformal coating. The actions would be 
required to be accomplished in accordance with the service bulletin 
described previously.
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been included in this notice to clarify this requirement.
    The FAA estimates that 450 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 4 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Required parts would cost 
approximately $410 per airplane. Based on these figures, the total cost 
impact of the proposed AD on U.S. operators is estimated to be 
$292,500, or $650 per airplane.
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished any of the proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    The regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting 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.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 adding the following new 
airworthiness directive:

Raytheon Corporate Jets, Inc. (Formerly de Havilland; Hawker 
Siddeley; British Aerospace, plc): Docket 94-NM-220-AD.

    Applicability: Model DH/BH/HS/BAe 125-1 to -700 series 
airplanes, inclusive, on which Modification 252740 has been 
installed; Model BAe 125-800A series airplanes, having constructor's 
numbers prior to number 258248; and Hawker 800 series airplanes, 
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 (b) 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 an electrical short in the standby static inverter 
due to the printed circuit boards being exposed to condensed 
moisture, accomplish the following:
    (a) Within 5 months of the effective date of this AD, remove the 
existing standby static inverter (type PC 250) and replace it with a 
Mod C Marathon/Flitetronics Inverter (type PC 250), in accordance 
with Raytheon Corporate Jets Hawker Service Bulletin SB.24-308-
7673A, Revision 1, dated July 11, 1994.
    (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, Standardization Branch, ANM-113, 
FAA, Transport 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, 
Standardization Branch, ANM-113.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (c) 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.

    Issued in Renton, Washington, on January 11, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-1135 Filed 1-17-95; 8:45 am]
BILLING CODE 4910-13-U