[Federal Register Volume 60, Number 30 (Tuesday, February 14, 1995)]
[Rules and Regulations]
[Pages 8297-8298]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-1849]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-NM-217-AD; Amendment 39-9128; AD 95-02-09]


Airworthiness Directives; British Aerospace Model ATP 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 British Aerospace Model ATP airplanes, that 
requires inspections to detect damage, overheating, and proper 
operation of the DC connections and cooling fans in certain transformer 
rectifier units (TRU), and repair or replacement, if necessary. This 
amendment is prompted by a report of the loss of all DC electrical 
power, except for the battery emergency bus, due to failure of the 
TRU's, which occurred during flight. The actions specified by this AD 
are intended to prevent such failures that could lead to loss of 
essential electrical power required to continue safe flight of the 
airplane.

DATES: Effective March 16, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 16, 1995.

ADDRESSES: The service information referenced in this AD may be 
obtained from Jetstream Aircraft, Inc., P.O. Box 16029, Dulles 
International Airport, Washington, DC 20041-6029. 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 Office of the Federal Register, 800 North Capitol 
Street, NW., suite 700, Washington, DC.

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: 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 British Aerospace Model 
ATP airplanes was published in the Federal Register on February 18, 
1994 (59 FR 8145). That action proposed to require inspections of the 
DC connections and cooling fans in certain transformer rectifier units 
(TRU) to detect damage or overheating and to ensure correct operation, 
and repair or replacement, if necessary.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the single comment received.
    The commenter supports the rule.
    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 added to this final rule to clarify this requirement.
    Additionally, The FAA has recently reviewed the figures it has used 
over the past several years in calculating the economic impact of AD 
activity. In order to account for various inflationary costs in the 
airline industry, the FAA has determined that it is necessary to 
increase the labor rate used in these calculations from $55 per work 
hour to $60 per work hour. The economic impact information, below, has 
been revised to reflect this increase in the specified hourly labor 
rate.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    The FAA estimates that 10 airplanes of U.S. registry will be 
affected by this AD, that it will take approximately 2 work hours per 
airplane to accomplish the required actions, and that the average labor 
rate is $60 per work hour. Based on these figures, the total cost 
impact of the AD on U.S. operators is estimated to be $1,200, or $120 
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.
    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, 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 [[Page 8298]] 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:

95-02-09  British Aerospace (Commercial Aircraft), Limited: 
Amendment 39-9128. Docket 93-NM-217-AD.

    Applicability: Model ATP airplanes equipped with Ferranti 
Transformer Rectifier Unit TR202A (Pt. No. 84/59100) or TR202B (Pt. 
No. 84/60040), 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 loss of essential electrical power required to 
continue safe flight of the airplane, accomplish the following:
    (a) Within 225 hours time-in-service after the effective date of 
this AD, and thereafter at intervals not to exceed 625 hours time-
in-service, accomplish paragraphs (a)(1), (a)(2), (a)(3), and (a)(4) 
of this AD.
    (1) Perform a visual inspection of the DC connections to detect 
any damage or overheating, in accordance with Ferranti Service 
Bulletin 24-20-171, dated September 1993. If any damage or 
overheating is found, prior to further flight, repair in accordance 
with a method approved by Manager, Standardization Branch, ANM-113, 
FAA, Transport Airplane Directorate.
    (2) Perform a torque loading inspection of each DC connection to 
ensure that torque loads are within the limits specified in Ferranti 
Service Bulletin 24-20-171, dated September 1993; and, during this 
inspection, ensure that each terminal stud is secure in its mounting 
by visually observing that the stud does not rotate; in accordance 
with Ferranti Service Bulletin 24-20-171, dated September 1993.
    (3) Perform a visual inspection of the cooling fan blades to 
detect any damage due to overheating, in accordance with Ferranti 
Service Bulletin 24-20-172, dated September 1993. If any damage is 
found, prior to further flight, replace the fan blade with a 
serviceable part in accordance with the airplane maintenance manual.
    (4) Perform a functional test of the operation of the cooling 
fan by energizing the relay and confirming that cooling air exits 
from the grill on top of the unit, in accordance with Ferranti 
Service Bulletin 24-20-172, dated September 1993. Prior to further 
flight, repair or replace any malfunctioning or damaged cooling fan 
or cooling fan relay, in accordance with the airplane maintenance 
manual.
    (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.
    (d) The inspections and test shall be done in accordance with 
Ferranti Service Bulletin 24-20-171, dated September 1993; and 
Ferranti Service Bulletin 24-20-172, dated September 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. Copies may be obtained from Jetstream Aircraft, Inc., P.O. Box 
16029, Dulles International Airport, Washington, DC 20041-6029. 
Copies may be inspected at the FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.
    (e) This amendment becomes effective on March 16, 1995.

    Issued in Renton, Washington, on January 19, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-1849 Filed 2-13-95; 8:45 am]
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